COATED STEEL PRODUCT

专利摘要:
a coated steel product is provided which has a steel product and a coating layer which includes a layer of zn-al-mg alloy disposed on a surface of the steel product, wherein the layer of zn-al-mg alloy mg has a zn phase, the zn phase contains a mg-sn intermetallic compound phase, and the coating layer consists of zn: more than 65.0%, al: more than 5.0% to less than 25 , 0%, mg: more than 3.0% to less than 12.5%, sn: 0.1% to 20.0% in terms of percentage (%) by weight, given the amounts of optional elements and impurities, and has a chemical composition that satisfies formulas 1 to 5 below: formula 1: bi + in <sn formula 2: y + la + ce = ca formula 3: si <sn formula 4: 0 = cr + ti + ni + co + v + nb + cu + mn <0.25 formula 5: 0 = sr + sb + pb + b <0.5.
公开号:BR112019015377A2
申请号:R112019015377-2
申请日:2018-01-26
公开日:2020-03-10
发明作者:Tokuda Kohei；Maki Jun；Goto Yasuto；Mitsunobu Takuya
申请人:Nippon Steel Corporation；
IPC主号:

专利说明:

Descriptive Report on the Invention Patent for COATED STEEL PRODUCTS.
TECHNICAL FIELD [001] The present invention relates to a coated steel product.
BACKGROUND TECHNIQUE [002] A wide variety of coated steel products are used in the field of construction materials. Many of them are steel products coated with Zn. Based on the long-lived needs of construction materials, research on the high corrosion resistance of Zn-coated steel products has been carried out for a long time, and several coated steel products have been developed. The first highly corrosion-resistant coated steel product for construction materials is a steel product coated with Zn-5% Al (Galfan-coated (galvanized) steel product) in which Al is added to a coating layer at the Zn-based to improve corrosion resistance. It is a well-known fact that Al is added to a coating layer to improve corrosion resistance. An Al phase is formed in the coating layer (specifically a Zn phase) with the addition of 5% Al, and the corrosion resistance is improved. Basically, a steel product coated with Zn55% AI-1.6% Si (galvalume steel product) is also a coated steel product with improved corrosion resistance for the same reason.
[003] Therefore, when the Al concentration is improved, basically, the corrosion resistance of the flat surface is improved. However, when the Al concentration is improved, this reduces the ability to protect against corrosion at a loss.
[004] Here, the attractive feature of a Zn-coated steel product is the corrosion protection effect on a base metal.
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2/144 if (steel product). In other words, on a cutting surface of a coated steel product, a cracked portion of a coating layer generated during processing, and an exposed portion of a base metal (steel product) that appears due to the exfoliation of the layer of coating, the coating layer is eluted in the vicinity of such portion before corrosion of the base metal (steel product) and the eluted coating component forms a protective film. This makes it possible to prevent the red rust of the base metal (steel product) to a certain extent.
[005] In general, a lower concentration of Al and a higher concentration of Zn are preferred for such effects. Therefore, a coated steel product that has high corrosion resistance in which the concentration of Al is suppressed in, for example, a relatively low concentration of 5% to 25% has been available for practical use in recent years. In particular, a coated steel product, in which the concentration of Al is suppressed at a low level and the Mg is contained in about 1% to 3%, has evident surface corrosion resistance and superior sacrificial corrosion protection capability those of a Galfan-coated steel product. Therefore, such a coated steel product has become a market trend and is widely known in the market today. For example, coated steel sheets described in Patent Documents 1 and 2 have also been developed as coated steel products containing certain amounts of Al and Mg and achieving high resistance to corrosion.
[006] In the field of building materials where long life is always desired, there is a demand to further improve resistance to flat surface corrosion and the ability to protect against sacrificial corrosion. A coated steel product with both properties is more preferred. In recent years, a favorable compatibility between the two properties has been achieved by the formation of
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3/144 alloy of a coating layer containing mainly Al and Mg. However, normally, the formation of alloy in a coating layer causes an increase in the hardness of the coating layer, and processability is also significantly impaired compared to the coating layer of a pure metal. Therefore, a coated steel product must have processability. In addition, since the hardness of the coating layer is associated with wear resistance, it is preferable to use effectively the properties obtained by forming the alloy of a coating layer. [007] However, such properties as corrosion resistance on the flat surface, sacrificial corrosion protection ability, processability and wear resistance are all difficult to be compatible with each other due to the fact that, for example, once these properties are improved, the other properties deteriorate.
[008] For example, as described above, it is particularly important to select the Al concentration from the point of view of corrosion resistance of the flat surface. A steel plate coated with Al as described in Patent Document 3 and a steel plate coated with ΑΙ-Zn as described in Patent Document 4 are available as a coated steel product that is mainly composed of Al and treated by means of checking of sacrificial corrosion protection capabilities. Meanwhile, as a coated steel product in which the concentration of Al is suppressed at a relatively low level of about 5% and resistance to flat surface corrosion is conferred to the coating layer, the coated steel sheets are revealed in the Patent Documents 5, 6, 7 and 8 [009] Patent Document 1: Japanese Patent Application Open to Public Inspection (JP-A) No. 2006-193791
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4/144 [0010] Patent Document 2: WO2011 / 001662 [0011] Patent Document 3: JP-A No. 2002-012959 [0012] Patent Document 4: JP-A No. 2015-214747 [0013] Document Patent 5: JP-A No. 2001 -115273 [0014] Patent Document 6: JP-A No. 2001-316791 [0015] Patent Document 7: JP-A No. 2010-275634 [0016] Patent Document 8: JP-A No. 2001 -64759
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION [0017] However, in the coated steel products described in Patent Documents 3 and 4, since the coating layer consists mainly of Al, the amount of Zn is limited, and the protective effect against sacrificial corrosion and the duration of the effect are significantly reduced. Therefore, it cannot be said that a favorable compatibility between flat surface corrosion resistance and sacrificial corrosion protection capability can be achieved while flat surface corrosion resistance is relatively dominant. As a result, a coated steel product that can replace the galvalume steel product has not yet spread to the market.
[0018] Furthermore, the coated steel products described in Patent Documents 5 to 8 also do not allow the developed Zn-AI (5% or more) -Mg (1% or more) coated steel product to have flat surface corrosion resistance and sacrifice corrosion protection capability comparable to Al-coated steel products. Therefore, it cannot be said that attractive properties are given to existing Zn-AI-Mg coated steel products .
[0019] Furthermore, it is difficult to say that any of the coated steel products achieves processability and wear resistance.
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5/144 [0020] An objective in one aspect of the present disclosure is to provide a coated steel product that achieves improved flat surface corrosion resistance and sacrificial corrosion protection capability and favorable compatibility between processability and wear resistance .
MEANS TO SOLVE PROBLEMS [0021] The means to solve problems include the following aspects.
[0022] <1> A coated steel product having a steel product and a coating layer including a layer of Zn-AI-Mg alloy disposed on a surface of the steel product;
[0023] in which the Zn-AI-Mg alloy layer has a Zn phase, and the Zn phase includes an Mg-Sn intermetallic compound phase, [0024] in which the coating layer consists, in terms of percentage (%) by mass [0025] Zn: more than 65.0%, [0026] Al: from more than 5.0% to less than 25.0%, [0027] Mg: more than 3.0 % less than 12.5%, [0028] Sn: from 0.1% to 20.0% [0029] Bi: from 0% to less than 5.0%, [0030] In: from 0% less from 2.0%, [0031] Ca: from 0% to 3.00% [0032] Y: from 0% to 0.5% [0033] La: from 0% to less than 0.5%, [0034 ] Ce: from 0% to less than 0.5%, [0035] Si: from 0% to less than 2.5%, [0036] Cr: from 0% to less than 0.25% [0037] Ti: from 0% to less than 0.25% [0038] Ni: from 0% to less than 0.25% [0039] Co: from 0% to less than 0.25%
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6/144 [0040] V: from 0% to less than 0.25% [0041] Nb: from 0% to less than 0.25%, [0042] Cu: from 0% to less than 0.25% [ 0043] Mn: from 0% to less than 0.25% [0044] Fe: from 0% to 5.0%, [0045] Sr: from 0% to less than 0.5%, [0046] Sb: from 0% to less than 0.5%, [0047] Pb: from 0% to less than 0.5%, [0048] B: from 0% to less than 0.5% and [0049] impurities and [0050] wherein the coating layer has a chemical composition that meets the following Formulas 1 to 5:
[0051] Formula 1: Bi + In <Sn [0052] Formula 2: Y + La + Ce <Ca [0053] Formula 3: Si <Sn [0054] Formula 4: 0 Cr + Ti + Ni + Co + V + Nb + Cu + Μη <0.25 [0055] Formula 5: 0 <Sr + Sb + Pb + B <0.5 [0056] where, in Formulas 1 to 5, each element symbol represents a content of an element corresponding in terms of percentage (%) by mass.
[0057] <2> The steel product coated according to <1>, in which the Mg-Sn intermetallic compound phase has an average grain size of less than 1 pm.
[0058] <3> The steel product coated according to <1> or <2>, in which, in a cross section of the Zn-AI-Mg alloy layer, the Mg-Sn intermetallic compound phase which has a grain size of less than 1 pm has an area fraction of 10% to 50% in relation to the Zn phase including the Mg-Sn intermetallic compound phase.
[0059] <4> The coated steel product according to any one of <1> to <3>, where, in a cross section of the layer of
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7/144 Zn-AI-Mg alloy, the Zn phase including the Mg-Sn intermetallic compound phase is present with a surface fraction of 3% or more relative to the cross section of the Zn-AI alloy layer -Mg.
[0060] <5> The coated steel product according to any of <1> to <4>, where, based on an X-ray diffraction image of a surface of the coating layer, the image being measured with the use of a Cu-Κα ray with an x-ray output at 40 kV and 150 mA, a specific intensity I (Mg-Sn intermetallic compound phase) = {I (22.8 ° intensity (cps)) + I (23.3 ° intensity (cps)) + I (24.2 ° intensity (cps)} / 3 χ I (background intensity at 20 ° (cps)) is 1.5 or more.
[0061] <6> The coated steel product according to any of <1> to <5>, wherein the coating layer has a Ca content of 0.05% to 3.00% by weight, and the Zn phase contains, like the Mg-Sn intermetallic compound phase, an MgCaSn phase and an MggSns phase, [0062] in which, based on an X-ray diffraction image of a coating layer surface , the image is measured using a Cu-Κα ray with an X-ray output at 40 kV and 150 mA, a specific intensity I (MgCaSn + MggSns) = {I (22.8 ° intensity (cps)) + I (26.3 ° intensity (cps))} / l (23.3 ° intensity (cps)) is less than 0.3 and I (23.3 ° intensity (cps)) is 500 cps or more.
[0063] <7> The steel product coated according to <5>, where the coating layer has an Mg content of more than 4.0% to less than 12.5% by weight, a Ca content from 0.05% to 3.00% by mass, and a Si content of 0.01% to 2.5% by mass, [0064] where, based on the X-ray diffraction image of the layer surface coating, the image is measured using a Cu-raioα ray with an x-ray output at 40 kV and 150 mA, in
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8/144 that a diffraction peak has a stronger intensity between the diffraction peaks that appear between 23.0 ° and 23.46 ° appear between 23.36 ° and
23.46 °.
[0065] <8> The steel product coated according to any of <1> to <7>, where the coating layer has a Ca content of 0.05% to 3.00% by weight and a Si content of 0.01% to 2.5% by weight, [0066] where the Zn-AI-Mg alloy layer has at least one selected from the group consisting of a phase of Ca-AI intermetallic compound -Si that has an average grain size of 1 pm or more and a phase of Mg-AI-Si intermetallic compound that has an average grain size of 1 pm or more.
[0067] <9> The steel product coated according to any of <1> to <8>, where the coating layer has a Ca content of 0.05% to 3.00% by weight, [ 0068] in which, in a cross-section of the ZnAI-Mg alloy layer, a phase of Ca-Zn-AI intermetallic compound that has a grain size of 1 pm or more is present with an area fraction of 5% or more in relation to the cross section of the Zn-AI-Mg alloy layer.
[0069] <10> The steel product coated according to any of <1> to <9>, where the coating layer has a Sn content of 3.00% to 20.00% by weight, and the following formula is satisfied: [0070] 0.05 <Sn / Zn, where each Sn and Zn represents the content of the corresponding element, [0071] where, in a cross section of the ZnAI-Mg alloy layer , a phase of Mg-Sn intermetallic compound that has a grain size of 1 pm or more is present with an area fraction of 3% or more relative to the section of the Zn-AIMg alloy layer.
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9/144 [0072] <11> The coated steel product according to any of <1> to <10>, in which, in a cross section of the Zn-AI-Mg alloy layer, a composite eutectoid structure by a Zn phase and an Al phase, and with a lamellar spacing less than 300 nm, it is present with an area fraction of 10% or more in relation to the cross section of the Zn-AI-Mg alloy layer.
[0073] <12> The coated steel product according to any of <1> to <11>, in which a ternary eutectic structure of Zn-AIMgZn ₂ has an area fraction of 0% to 5% in one section cross section of the Zn-AI-Mg alloy layer.
[0074] <13> The steel product coated according to any of <1> to <9>, where the Sn content of the coating layer is from 0.10% to less than 3.00%.
[0075] <14> The coated steel product according to any of <1> to <13>, wherein the coating layer has an Al-Fe alloy layer between the steel product and the alloy layer of ZnAI-Mg.
EFFECT OF THE INVENTION [0076] An objective in one aspect of the disclosure is to provide a coated steel product that achieves improved flat surface corrosion resistance and sacrificial corrosion protection capability and favorable compatibility between processability and wear resistance.
BRIEF DESCRIPTION OF THE DRAWINGS [0077] Figure 1 is an example of the ternary eutectic structure in a coating layer based on existing Zn-AI-Mg (Zn-11% AI-3% Mg-0.2% Si).
[0078] Figure 2 is an image of SEM reflection electrons showing an example of the coating layer according to the development.
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10/144 [0079] Figure 3 is an image of SEM reflection electrons showing an enlarged image of the Zn phase portion in Figure
2.
[0080] Figure 4 is an image of SEM reflection electrons showing another example of the coating layer according to the description.
[0081] Figure 5 is an image of SEM reflection electrons showing an enlarged image of the neighborhood of the massive Mg-Sn intermetallic compound phase in Figure 4.
[0082] Figure 6 is an image of SEM reflection electrons showing another example of the coating layer of the development.
[0083] Figure 7 is an electronic SEM reflection image showing an enlarged image of the eutectoid structure composed of the Zn phase and the Al phase, and which has a lamellar spacing of less than 300 nm (thin eutectoid Zn-AI structure) in Figure 6.
[0084] Figure 8 is an image of SEM reflection electrons showing another example of the coating layer according to the invention.
[0085] Figure 9 is an enlarged image (SEM electronic reflection image) of the coating structure in the frame of Figure 8.
[0086] Figure 10 is an enlarged image (TEM image) of the Fe interface neighborhood of the coating layer shown in Figure 8.
[0087] Figure 11A is an electron beam diffraction image of the amorphous intermetallic compound phase (13) in Figure 10.
[0088] Figure 11B is an EDS analysis spectrum of the phase of the amorphous intermetallic compound (13) in Figure 10.
[0089] Figure 12A is an electron beam diffraction image of the needle-like intermetallic compound phase (14) in Figure 10.
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11/144 [0090] Figure 12B is a spectrum of EDS analysis of the needle-like intermetallic compound phase (14) in Figure 10.
[0091] Figure 13 is an electronic SEM reflection image to explain a method for determining an eutectoid structure composed of a Zn phase and an Al phase, and which has a lamellar spacing of less than 300 nm (Zn- eutectoid structure) Thin AI) and measuring a fraction of that area.
[0092] Figure 14 is an image of SEM reflection electrons to explain a method of determining a ternary eutectic structure of Zn-AI-MgZn2 and measuring a fraction of its area.
DESCRIPTION OF THE MODALITIES [0093] Hereinafter, an example of the disclosure will be described.
[0094] In the disclosure, the indication% of the content of each element of a chemical composition means% by mass.
[0095] In addition, a numeric range expressed using for means a range that includes the numeric values before and after a as the lower limit and the upper limit.
[0096] A numerical range when the numerical value described before or after it is added with above or below which means a range that does not include the numerical value as the lower limit or the upper limit.
[0097] The content of an element of a chemical composition can be expressed as the quantity of elements (for example, quantity of Zn or quantity of Mg) or concentration of elements (for example, concentration of Zn or concentration of Mg).
[0098] The term step includes not only an independent step, but also a step, even in a case where the step cannot be clearly distinguished from other steps, as long as the intended purpose of the step is achieved.
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12/144 [0099] The term corrosion resistance on the flat surface refers to the corrosion resistance property of a coating layer (specifically a layer of Zn-AI-Mg alloy).
[00100] The term sacrificial corrosion protection capability refers to the property of suppressing corrosion of an exposed portion of a base metal (steel product) (for example, a cut end surface of a coated steel product , a processing-induced crack in a coating layer and a portion of a base metal (steel product) exposed due to the exfoliation of a coating layer).
[00101] The coated steel product of the disclosure is a melt-coated steel sheet that has a steel product and a coating layer including a layer of Zn-AI-Mg alloy disposed on the surface of the steel product, where the Zn-AI-Mg alloy layer has a Zn phase, the Zn phase contains a Mg-Sn intermetallic compound phase, and the coating layer has a given chemical composition.
[00102] The coated steel product of the development having the configuration described above manages to improve the corrosion resistance on the flat surface and the ability to protect against sacrificial corrosion and a favorable compatibility between processability and wear resistance. The coated steel product of the development was found based on the following results.
[00103] The inventors obtained the following results in various properties of the coating layer of a steel product coated with Zn-AI-Mg.
[00104] In order to obtain corrosion resistance on the flat surface at a level equal to or greater than the most excellent corrosion resistant Zn-AI-Mg coated steel plate in recent years, the concentration of Al needs to be at least less than 5% and the concentration
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13/144 Mg needs to be at least more than 3%. Favorable compatibility between flat surface corrosion resistance and sacrifice corrosion protection capability cannot be achieved for Zn-AI-Mg coated steel sheets existing below these concentrations.
[00105] However, the sacrificial corrosion protection capability can be imparted to a coating layer allowing the coating layer to contain a certain amount of Sn to cause a change in the constitutional phase of the coating layer (specifically, the coating layer). alloy of Zn-AI-Mg), in addition to controlling the concentration of Al and the concentration of Mg. Specifically, the sacrificial corrosion protection capacity can be exercised at a level that could not be achieved by conventional steel products coated with molten Zn, causing a phase of Mg-Sn intermetallic compound to be deposited mainly in a phase of Zn formed in the Zn-AI-Mg alloy layer.
[00106] Since an MgSn intermetallic compound phase is contained in a Zn phase, the hardness of the Zn phase increases without deteriorating processability. In addition, excellent wear resistance is also achieved due to the fact that processability at a level equivalent to that of conventional Zn-AI-Mg coated steel products is maintained by properly regulating the concentrations of Zn, Al, Mg and Sn , while the chemical composition of the coating layer is a high alloy composition and the hardness of the coating layer is maintained at a high level by carrying out the high alloy composition as a chemical composition of the coating layer.
[00107] Consequently, it was found that the coated steel sheet according to the disclosure can be a coated steel product that manages to improve the corrosion resistance on the flat surface and
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14/144 the ability to protect against corrosion and a favorable compatibility between processability and wear resistance.
[00108] In particular, since the coated steel product of the development is excellent in the ability to protect against sacrificial corrosion, the corrosion resistance of the cut end surface is improved.
[00109] Here, the Mg-Sn intermetallic compound phase (hereinafter also referred to as the MCSB thin phase for convenience) encompasses the phases of the intermetallic compound corresponding to the following (1) to (5). The Mg-Sn intermetallic compound phase can form a solid solution with an interstitial element such as Si.
[00110] (1) Mg ₂ Sn phase [00111] (2) Mg ₉ Sn ₅ phase [00112] (3) Substituted Mg ₂ phase and MggSns phase (
Mg ₂ Sn and MggSns phase as a substituted phase) where Sn is partially replaced by at least one of Bi, In, Cr, Ti, Ni, Co, V, Nb, Cu or Mn.
[00113] (4) Mg ₂ Sn phase replaced and MggSns phase phase (Mg ₂ Sn phase and MggSns phase as a substituted phase) in which Mg is partially replaced by at least one of Ca, Y, La, Ce or [00114] (5) Mg ₂ Sn phase replaced and MggSns phase (phase
Mg ₂ Sn and MggSns phase as a substituted phase) where Mg is partially replaced by at least one of Ca, Y, La, or Ce, and Sn is partially replaced by at least one among Bi, In, Cr, Ti, Ni, Co, V, Nb, Cu or Mn [00115] These substituted phases of Mg ₂ Sn phase and MggSns phase can be collectively referred to as the substituted phase of Mg ₂ Sn phase.
[00116] Hereinafter, the coated steel product of the disclosure will be described in detail.
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15/144 [00117] A steel product to be coated will be described.
[00118] The shape of the steel product is not particularly limited. Examples of the steel product include processed steel products such as steel pipes, civil engineering construction materials (such as sealing conduits, corrugated pipes, drainage ditch covers, sand protection plates, screws, wire mesh, railings). protection and water blocking walls), electrical appliance members (such as housings of external air conditioner units), auto parts (such as undercarriage members), as well as steel plates. For example, various methods of plastic processing, such as press processing, roll forming and bending processing, can be used for processing formation.
[00119] There are no particular limitations on the materials for the steel product. For example, several steel products, such as steel in general, pre-coated steel in Ni, steel calmed by aluminum, extremely low carbon steel, high carbon steel, various high intensity steel products and some high alloy steel products (such as steel containing a strengthening element, such as Ni or Cr) are available.
[00120] Furthermore, the steel product is not particularly limited in terms of conditions for the production method of steel products, the method of producing steel sheets or the like (such as the hot rolling method, pickling method or cold rolling).
[00121] The steel product can be a pre-coated steel product prepared by pre-covering.
[00122] Next, a coating layer will be described.
[00123] A coating layer includes a layer of Zn-AI-Mg alloy. A coating layer may include an Al-Fe alloy layer, in addition to a Zn-AI-Mg alloy layer. A layer
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16/144 of Al-Fe alloy is present between a steel product and a layer of Zn-AI-Mg alloy.
[00124] In other words, the coating layer can have a single layer structure of a Zn-AI-Mg alloy layer or a layered structure including a Zn-AIMg alloy layer and an Al alloy layer -Faith. In the case of the layered structure, the Zn-AI-Mg alloy layer is desirably a layer that forms the surface of the coating layer.
[00125] Note that an oxide film of elements constituting the coating layer is formed with a thickness of about 50 nm on the surface of the coating layer. However, as the thickness is thin in relation to the thickness of the entire coating layer, it is considered that the oxide film does not constitute the main body of the coating layer.
[00126] Here, the thickness of the Zn-AI-Mg alloy layer is, for example, from 2 pm to 95 pm (preferably from 5 pm to 75 pm).
[00127] However, the thickness of the entire coating layer is, for example, about 100 pm or less. As the thickness of the entire coating layer depends on the coating conditions, the upper and lower limits of the thickness of the entire coating layer are not particularly limited. For example, the thickness of the entire coating layer is associated with the viscosity and specific gravity of a coating bath in a normal melt coating method. In addition, the weight of the coating is adjusted by the drawing speed of a steel plate (coating base plate) and the intensity of the cleaning. Therefore, the lower thickness limit of the entire coating layer is considered to be about 2 pm.
[00128] However, due to the weight and uniformity of a coating metal, a coating layer that can be produced
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17/144 by the melt coating method has a thickness of about 95 pm.
[00129] The thickness of a coating layer can be determined freely depending on the stretching speed of a coating bath and cleaning conditions, indicating that the formation of a coating layer with a thickness of 2 to 95 pm is not particularly difficult in terms of production.
[00130] Next, an Al-Fe alloy layer will be described.
[00131] An Al-Fe alloy layer is formed on the surface of a steel product (specifically between a steel product and a Zn-AI-Mg alloy layer), and the AIsFe phase is a layer of the phase main structure. An Al-Fe alloy layer is formed by atomic diffusion between a base metal (steel product) and a coating bath. In a case where the melt coating method is used as a production method, it is likely that an Al-Fe alloy layer will be formed into a coating layer containing Al as an element. As the coating bath contains Al at a certain concentration or more, an AIsFe phase is formed as the most dominant phase. However, atomic diffusion takes time, and a portion close to the base metal may have a high concentration of Fe. Therefore, the Al-Fe alloy layer may partially contain small amounts of an AlFe phase, an AhFe, a phase of AlsFe2 and the like. In addition, as Zn is also contained in a certain concentration in the coating bath, the Al-Fe alloy layer also contains a small amount of Zn.
[00132] Regarding corrosion resistance, there is no significant difference between an AIsFe phase, an AhFe phase, an AlFe phase and an AIsFez phase. The term corrosion resistance used here means corrosion resistance in a location that is not affected by
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18/144 welding. The thickness of the Al-Fe alloy layer in the coating layer is small and the degree of corrosion resistance is less than that of the Zn-AI-Mg alloy layer. Thus, there is no significant difference in the corrosion resistance of the entire coating layer, even when the proportion of these phases varies.
[00133] Here, in a case where Si is contained in the coating layer, Si is particularly easily incorporated into the Al-Fe alloy layer, which can result in an Al-Fe-Si intermetallic compound phase . There is an AlFeSi phase as an intermetallic compound phase to be identified. For example, the phases α-, β-, q1- and q2-AIFeSi exist as isomers. Therefore, these AlFeSi phases can be detected in the Al-Fe alloy layer. The Al-Fe alloy layer containing these AlFeSi phases is also called the Al-Fe-Si alloy layer.
[00134] The Al-Fe-Si alloy layer is smaller in thickness than the Zn-AI-Mg alloy layer and therefore has only a small impact on the corrosion resistance of the entire coating layer.
[00135] In addition, in a case where several pre-coated steel products are used as the base coating material (such as a base coat plate), the structure of the Al-Fe alloy layer may change depending on the amount of pre-coverage adhesive. Specifically, there are cases such as a case where a pure metal layer used for precoat remains around the Al-Fe alloy layer, a case in which an intermetallic compound phase (for example, an AI3N1 phase) in that the components of a Zn-AI-Mg alloy layer and precoat components are bonded together to form an alloy layer, a case in which an Al-Fe alloy layer containing elements replacing some Al atoms and atoms of Fe is formed, and a ca
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19/144 so that an Al-Fe-Si alloy layer containing elements that replace some Fe atoms and Si atoms is formed. In any case, these alloy layers are also smaller in thickness than the Zn-AI-Mg alloy layer and thus have only a small impact on the corrosion resistance of the entire coating layer.
[00136] In other words, the Al-Fe alloy layer is a layer including alloy layers in the various aspects described above, in addition to an alloy layer composed mainly of the AI ₅ Fe phase.
[00137] The Al-Fe alloy layer has a thickness of, for example, from 0 pm to 5 pm (usually from 100 nm to 5 pm).
[00138] This means that the Al-Fe alloy layer is not necessarily formed. However, in general, when a coating layer is formed by the coating method by melting with a coating composition as specified in the disclosure, an Al-Fe alloy layer having a thickness of 100 nm or more is formed between the product. steel and the Zn-AI-Mg alloy layer. The lower limit of Al-Fe alloy layer thickness is not particularly limited. It has been found that an Al-Fe alloy layer is inevitably formed when a melt-containing layer containing Al is formed. In addition, it is empirically determined that a thickness of about 100 nm is the thickness in a case where the formation of an Al-Fe alloy layer is further suppressed, which is a thickness that ensures sufficient adhesion between a coating layer and a base metal (steel product). It is difficult to form an Al-Fe alloy layer thinner than 100 nm with the melt coating method, due to the fact that the Al concentration is always high, unless special measures are taken. However, even in a case where the Al-Fe alloy layer has
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20/144 thickness less than 100 nm or no Al-Fe alloy layer is formed, it would not have a major impact on the performance of the coating.
[00139] However, in a case where the Al-Fe alloy layer has a thickness of 5 pm or more, the Al component is missing from a Zn-AI-Mg alloy layer to form the alloy layer of Alpha, and adhesion and processability of the coating layer tend to deteriorate extremely. Therefore, the thickness of the Al-Fe alloy layer is limited to 5 pm or less [00140] The Al-Fe alloy layer is also closely associated with the concentration of Al and the concentration of Sn. In general, as the concentration of Al and the concentration of Sn increase, the growth rate tends to increase.
[00141] The Al-Fe alloy layer is generally composed mainly of an Al 5 Fe phase. Therefore, an example of the chemical composition of the Al-Fe alloy layer is a composition including Fe: from 25% to 35% , Al: 65% to 75%, Zn: 5% or less, and remainder: impurities.
[00142] Normally, the Zn-AI-Mg alloy layer is larger in thickness than the Al-Fe alloy layer. Therefore, the Al-Fe alloy layer as a coated steel sheet contributes to a resistance to flat surface corrosion to a lesser extent than the Zn-AI-Mg alloy layer. However, the Al-Fe alloy layer contains Al and Zn as elements resistant to corrosion in certain concentrations or more, as estimated from the results of the component analysis. Therefore, the Al-Fe alloy layer has certain levels of sacrificial corrosion protection capability and corrosion barrier effects on the base metal (steel product).
[00143] It is difficult to confirm the extent to which a thin layer of Al-Fe alloy alone contributes to corrosion resistance by determining 870190071281, of 7/25/2019, p. 28/194
21/144 quantitative nation. However, for example, in the case of a sufficiently thick Al-Fe alloy layer, it is possible to assess the corrosion resistance of the Al-Fe alloy layer by carefully removing a Zn-AI-Mg alloy layer in the Al-Fe alloy by cutting from the surface of a coating layer using end milling or the like and conducting a corrosion test. An Al-Fe alloy layer contains an Al component and a small amount of a Zn component. In a case where an Al-Fe alloy layer is present, red rust is formed as stains, which differs from a case in which a base metal (steel product) is exposed without an Al-alloy layer -Fe and totally covered with red rust.
[00144] Furthermore, when a cross section of the coating layer that reached a stage just before the formation of red rust on the base metal (steel product) is observed during the corrosion test, it can be confirmed that, even if the Alloy layer of Zn-AI-Mg As the top layer is eluted and rusted, the Al-Fe alloy layer is left exclusively to prevent corrosion of the base metal (steel product). This is due to the fact that the Al-Fe alloy layer is electrochemically superior to the Zn-AI-Mg layer, but inferior to the base metal (steel product). From these facts, it can be considered that the Al-Fe alloy layer also has a certain level of corrosion resistance.
[00145] From the point of view of corrosion, it is more preferable that the Al-Fe alloy layer is thicker. This is effective in slowing the time for the formation of red rust. However, since a thick layer of Al-Fe alloy causes a significant deterioration in the processability of the coating, the thickness is preferably equal to or less than a certain thickness. An appropriate thickness is known from the point of view of processability. A CA
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22/144 Al-Fe alloy layer preferably has a thickness of 5 pm or less, so that cracks generated from the Al-Fe alloy layer for coating during a V-bend test or similar and the amount of dust are reduced. The thickness is most preferably 2 pm or less.
[00146] Next, a chemical composition of a coating layer will be described.
[00147] The component composition of a Zn-AI-Mg alloy layer contained in a coating layer is substantially maintained even in a case where the component composition ratio between the coating bath corresponds to the Zn alloy layer -AI-Mg. In the melt coating method, a reaction to form an Al-Fe alloy layer is completed in a coating bath. Therefore, usually, the formation of an Al-Fe alloy layer causes only small decreases in the Al and Zn components of a Zn-AI-Mg alloy layer.
[00148] In order to achieve the improvement of flat surface corrosion resistance and protection capacity against sacrificial corrosion and a favorable balance between processability and wear resistance, the chemical composition of the coating layer is determined as follows.
[00149] In particular, the coating layer is allowed to contain certain amounts of Mg and Sn in a Zn concentration greater than 65.0% as in the chemical composition described below, thus making it possible to significantly improve the corrosion protection capacity sacrifice of the Zn phase in the Zn-AI-Mg alloy layer and acquire high-level sacrifice corrosion protection and high-level flat surface corrosion resistance in the presence of Al. Processability and strength can also be achieved wear.
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23/144 [00150] Specifically, the chemical composition of the coating layer is a chemical composition consisting of [00151] Zn: more than 65.0%, [00152] Al: from more than 5.0% to less than 25 , 0%, [00153] Mg: from more than 3.0% to less than 12.5%, [00154] Sn: from 0.1% to 20.0% [00155] Bi: from 0% to less than 5.0%, [00156] In: from 0% to less than 2.0%, [00157] Ca: from 0% to 3.00% [00158] Y: from 0% to 0.5% [00159] La: from 0% to less than 0.5%, [00160] Ce: from 0% to less than 0.5%, [00161] Si: from 0% to less than 2.5%, [00162] Cr: from 0% to less than 0.25% [00163] Ti: from 0% to less than 0.25% [00164] Ni: from 0% to less than 0.25% [00165] Co: from 0% less from 0.25% [00166] V: from 0% to less than 0.25% [00167] Nb: from 0% to less than 0.25%, [00168] Cu: from 0% to less than 0.25 % [00169] Mn: from 0% to less than 0.25% [00170] Fe: from 0% to 5.0%, [00171] Sr: from 0% to less than 0.5%, [00172] Sb : from 0% to less than 0.5%, [00173] Pb: from 0% to less than 0.5%, [00174] B: from 0% to less than 0.5% in terms of percentage (%) mass and impurities.
[00175] Note that the chemical composition of the coating layer satisfies the following Formulas 1 to 5.
[00176] Formula 1: Bi + In <Sn
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24/144 [00177] Formula 2: Y + La + Ce <Ca [00178] Formula 3: Si <Sn [00179] Formula 4: 0 Cr + Ti + Ni + Co + V + Nb + Cu + Mn <0, 25 [00180] Formula 5: 0 <Sr + Sb + Pb + B <0.5 [00181] In Formulas 1 to 5, each element symbol represents the content of the corresponding element in terms of percentage (%) by mass.
[00182] In the chemical composition of the coating layer, Bi, In, Ca, Y, La, Ce, Si, Cr, Ti, Ni, Co, V, Nb, Cu, Mn, Fe, Sr, Sb, Pb and B are optional components. In other words, these elements are not necessarily included in the coating layer. In a case where these optional components are included, the content of each optional element is preferably within the corresponding range described below.
[00183] Here, the chemical composition of the coating layer is the average chemical composition of the entire coating layer (in a case where the coating layer has a single layer structure of a Zn-AI-Mg alloy layer, in which case the coating layer has the average chemical composition of a Zn-AI-Mg alloy layer and the coating layer has a stratified structure of an Al-Fe alloy layer and a ZnAI-Mg alloy layer , or a case where the coating layer has the average chemical composition of an Al-Fe alloy layer and a combined Zn-AI-Mg alloy layer).
[00184] Normally, in the melt coating method, the chemical composition of the Zn-AI-Mg alloy layer is substantially the same as the coating bath due to the fact that the coating layer formation reaction is completed in coating bath in almost all cases. In addition, in the melt coating method, the Al-Fe alloy layer is instantaneous. Petition 870190071281, of 7/25/2019, p. 32/194
25/144 formed and grown immediately after being immersed in the coating bath. The reaction of forming the Al-Fe alloy layer is completed in the coating bath, and the Al-Fe alloy layer is often sufficiently smaller in thickness than the Zn-AI-Mg alloy layer.
[00185] Therefore, unless special heat treatment, such as heating alloy treatment, is conducted, the average chemical composition of the entire coating layer is substantially equal to the chemical composition of the Zn-AI-Mg alloy layer and therefore, the Al-Fe alloy layer components can be ignored.
[00186] Hereinafter, each element of the coating layer will be described below.
ZN: MORE THAN 65.0% [00187] Zn is a necessary element to achieve the ability to protect against sacrificial corrosion, as well as corrosion resistance of the flat surface. Regarding the concentration of Zn, considering the atomic composition ratio, as the coating layer is composed of elements of low specificity such as Al and Mg, Zn needs to have the highest proportion in the atomic composition.
[00188] When the Zn concentration is 65.0% or less, an Al phase is formed mainly in the Zn-AI-Mg alloy layer, resulting in the lack of a Zn phase to guarantee the protection capacity against sacrificial corrosion. In addition, when an Al phase increases, since Al tends to form a solid solution with several elements compared to Zn, the types of phases constituting the coating layer vary. In addition, a desired distribution structure of the intermetallic compound phases cannot be maintained.
[00189] Therefore, the Zn concentration is adjusted to more than 65.0%. The concentration of Zn is preferably 70% or more. O
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26/144 upper limit of the Zn concentration is the concentration of elements other than Zn and a balance other than impurities.
AL: FROM MORE THAN 5.0% TO LESS THAN 25.0% [00190] Al is a necessary element to allow the coating layer (particularly the Zn-AI-Mg layer) to contain elements other than Zn. It is originally difficult for the Zn coating layer (Zn layer) to contain other elements. For example, elements such as Mg, Ca and Si cannot be added in high concentrations. However, it is possible to produce a Zn-AI-Mg alloy layer containing these elements, allowing the Zn coating layer (Zn layer) to contain Al.
[00191] Al forms an Al phase that provides resistance to corrosion on the flat surface and plastic deformability, and also contributes to the formation of an Al-Fe alloy layer. Al is an essential element also to ensure adhesiveness.
[00192] When the concentration of Al is 5.0% or less, it tends to be difficult for a coating layer to contain alloy elements that confer properties, in addition to Mg and Ca. In addition, a low density of Al results in formation of an Al phase in a large amount of phase in relation to the mass-based content compared to Zn. However, when the Al concentration is 5.0% or less, the Zn-AI-Mg alloy layer tends to consist mainly of a Zn phase. This can lead to a significant reduction in corrosion resistance of the flat surface. From the point of view of corrosion resistance, it is not preferred that a Zn phase becomes the first phase of the Zn-AI-Mg alloy layer. In a case where a Zn phase becomes the first phase as described below, a ternary eutectic structure of Zn-AI-MgZn2 with low corrosion resistance and flat surface processability is likely to be poor, resulting in a tendency to deteriorate resistance
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27/144 to flat surface corrosion and processability.
[00193] In addition, when the aluminum concentration is 5.0% or less, an MgZn2 phase that has poor plastic deformability tends to grow coarse like a primary crystal in the layer of a Zn-AI-Mg alloy, and the The processing capacity of the coating layer tends to deteriorate significantly.
[00194] Therefore, the lower limit of the concentration of Al is defined as more than 5.0% (preferably 10.0% or more).
[00195] However, when the concentration of Al increases, the proportion of an Al phase increases rapidly in the layer of a Zn-AI-Mg alloy, and the proportions of a Zn phase and an MgZn2 phase necessary to confer a decrease of sacrifice corrosion protection capability. As a result, corrosion resistance of the flat surface and processability are improved.
[00196] However, the resulting configuration is close to a configuration lacking the ability to protect against sacrificial corrosion. In addition, when the concentration of Al increases excessively, a wide variety of elements are incorporated into an Al phase as described above, which does not lead to the formation of a Zn phase including a thin MCSB phase. In a case where a coating layer is formed by the melt coating method, the thickness of an Al-Fe alloy layer tends to increase. As a result, the Al phase contains large amounts of Mg and Zn, resulting in the formation of an Al phase with very poor corrosion resistance and plastic deformability. The formation of such an Al phase is not preferred from the point of view of ensuring processability.
[00197] Therefore, the upper limit of the concentration of Al is defined as less than 25.0% (preferably 23.0% or less).
MG: MORE THAN 3.0% TO LESS THAN 12.5%
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28/144 [00198] Mg is a necessary element to provide sacrificial corrosion protection capacity. Mg is also an element necessary to allow a thin MCSB phase to be formed in a Zn phase. Normally, when Mg is contained in the layer of a Zn-AI-Mg alloy, a phase of MgZn ₂ that is capable of protecting against sacrificial corrosion is formed. However, the sacrificial corrosion protection capacity of the MgZn ₂ phase is less than that of the thin MCSB phase, and the MgZn ₂ phase is a very fragile intermetallic compound phase. Therefore, the amount of the MgZn ₂ phase is preferably small.
[00199] When the Mg concentration is 3.0% or less, it is impossible to form the intermetallic compound phase (including the thin MCSB phase and the MgZn ₂ phase) necessary to confer the corrosion resistance of the flat surface and the ability to protect from sacrificial corrosion, in a sufficient amount. In addition, as the amount of the Zn phase increases, the Zn phase becomes the first phase and the proportion of ternary eutectic structure of Zn-AI-MgZn ₂ increases, which is not preferred in view of processability and strength corrosion.
[00200] Therefore, the lower limit of the Mg concentration is set to more than 3.0%.
[00201] Considering the amount of the thin MCSB phase formed, it is preferable that the Mg concentration is sufficiently high, and the Mg is contained at a concentration of one third (1/3) or more of the Sn concentration based on the calculation specific gravity. In addition, from the point of view of resistance to flat surface corrosion and the ability to protect against sacrificial corrosion, it is preferable that Mg is contained at a concentration of one third (1/3) or more of the concentration of Sn. Therefore, the lower limit of the Mg concentration is preferably greater than 5.0%.
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29/144 [00202] However, when the Mg concentration is 12.5% or more, the amount of the MgZn ₂ phase increases rapidly, resulting in loss of plastic deformability of the Zn-AIMg alloy layer and deterioration of processability .
[00203] Therefore, the upper limit of the Mg concentration is adjusted to less than 12.5% (preferably 10.0% or less).
SN: 0.1% to 20.0%, BI: 0% TO LESS THAN 5.0%, IN: 0% TO LESS 2.0%, SINCE BI + IN <SN [00204] Sn it is an element that is included in a Zn phase and is necessary to form a thin MCSB phase that provides a high capacity for protection against sacrificial corrosion.
[00205] Here, Sn, Bi and In do not form an intermetallic compound phase together with Al and Zn in a coating bath, and always bind to Mg in order to form an intermetallic compound phase. Specifically, in a case where Sn, Bi and In are contained separately in a coating bath, compounds such as Mg ₂ Sn and MggSns, MggBi ₂ and Mggln are formed, respectively. When Sn, Bi and In are contained in 0.10% or more, these phases of intermetallic compound are formed. Among these phases of intermetallic compound, Mg ₂ Sn is more excellent, considering the fact that Mg ₂ Sn has resistance to flat surface corrosion and the ability to protect against corrosion of sacrifice, and is easily incorporated into a Zn phase rich in deformability plastic that is soft enough to process. MggBi ₂ and Mggln are relatively inferior to Mg ₂ Sn in terms of a balance between properties such as corrosion resistance on the flat surface, ability to protect against corrosion and processability.
[00206] Therefore, for the formation of at least Mg ₂ Sn as a thin MCSB phase, Sn is an essential element and the lower limit of the Sn concentration is adjusted to 0.1% or more (preferably
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30/144
3.0 or more).
[00207] Although Bi and In are optional elements, when Bi and In are contained together with Sn, Sn in MgzSn they are partially replaced by Bi and In. In other words, a substituted derivative of MgzSn phase (thin MCSB phase) in that Sn is partially replaced by at least one of Bi or em is formed. The formation of such a substituted MgzSn phase makes it possible to adjust the optimum amount of Mg to be eluted to provide corrosion resistance on the flat surface and the ability to protect against sacrificial corrosion. For the formation of the substituted MgzSn phase, Sn, Bi, and In need to be contained under conditions that satisfy Bi + Na <Sn. Unless conditions are met, a compound such as MgaB2 or Mgaln is formed independently, resulting in deterioration of flat surface corrosion resistance and processability.
[00208] In a case where Bi and In are contained, the lower limits of the concentrations of Bi and In are each preferably 0.1% or more, more preferably 0.3% or more.
[00209] However, high levels of Sn, Bi and In cause an increase in the Mg elution rate of the Zn-AI-Mg alloy layer and deterioration of corrosion resistance on the flat surface. In particular, high levels of Bi and In impair the processability of the coating layer. Therefore, these elements must satisfy Sn <20.0%, Bi <5.0% and In <2.0% (preferably, Sn <5%, Bi <0.5% and In <0.3%), respectively .
[00210] In a case where the concentration of Sn is from 3.00% to 20.00% and Sn and Zn represent their element concentrations, when the Formula: 0.05 <Sn / Zn is satisfied, the concentration of Sn contained in the Zn-AI-Mg alloy layer relatively increases. Therefore, a thin MCSB phase is contained in the Zn phase in the Zn-AI-Mg alloy layer, and an MCSB phase which has a size of Petition 870190071281, of 7/25/2019, p. 38/194
31/144 grain of 1 μιτι or more (also referred to as massive MCSB phase) is deposited. The effect of incorporating a
MCSB will be described later.
[00211] In addition, when the concentration of Sn is 0.1% to less than 3.0%, there is a greater tendency to improve the ability to protect against corrosion of sacrifice in T bending. In general, in one case in which the concentration of Sn is high, an excellent ability to protect against sacrificial corrosion is conferred. However, in relation to properties involving various factors, such as resistance to flat surface corrosion, processing capacity (hardness) and protection against corrosion by sacrificing the coating layer, as in the case of T-bending, it is preferable to suppress the concentration of Sn at a low level in order to slightly reduce the effects of sacrificial corrosion protection.
CA: from 0% to 3.00%, Y: from 0% to 0.5%, LA: from 0% to less than 0.5%, EC: from 0% to less than 0.5%, provided that Y + LA + CE <CA [00212] Mg in MgzSn is partially replaced by Ca, Y, La and Ce. In other words, a substituted derivative of MgzSn phase (thin MCSB phase) in which Mg is partially replaced by at least one of Ca, Y, La, Ce, or is formed. The formation of such a substituted MgzSn phase also makes it possible to adjust the optimum amount of Mg to be eluted to provide resistance to corrosion of the flat surface and the ability to protect against sacrificial corrosion.
[00213] For the formation of the substituted MgzSn phase, it is preferable that the lower limit of calcium concentration is 0.05% or more, the lower limit of Y concentration is 0.1% or more, and the limit of each of the La and Ce concentrations is 0.1% or more.
[00214] Meanwhile, the Ca content can be up to 3.00%, the content
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32/144 of Y can be up to 0.5%, each of the La and Ce levels can be less than 0.5% (preferably the Ca content can be up to 1.00%, the content of Y can be up to 0.3%, and each of the La and Ce levels can be up to 0.3%). When the concentrations of Ca, Y, La and Ce exceed these ranges, each of the elements Ca, Y, La and Ce tends to form an intermetallic compound phase composed mainly of them, resulting in the deterioration of corrosion resistance and processability. In addition, Y + La + Ce <Ca must be satisfied from the ratio of substitution positions in the thin MCSB phase. In a case where conditions are not met, each of the elements Y, La and Ce forms the phase of the mostly composed intermetallic compound, and the corrosion resistance of the flat surface deteriorates greatly.
[00215] The effect of the substitution causes MggSn to undergo a structural change, resulting in an excellent ability to protect against corrosion from sacrifice in the long term. Although it is difficult to make a clear distinction between the substituted MggSn phases (the substituted MggSn phases, including a substitution with at least one of Bi, Na, Ca, Y, La or Ce), it is believed that the elution rate of Mg from an MggSn phase can be adequately controlled by replacing it with any of the elements. In addition, it is believed that substitution with any of the elements causes an MggSn phase to be altered to have a MggSns structure described later. Once Bi, In, Ca, Y, La or Ce (especially Ca) is contained, it simply causes a substituted MggSn phase to form, and it also causes a MggSn phase to change in its crystalline form, thus facilitating the formation of an MggSns phase. Such training effects will be described later.
[00216] As described above, in a case where a layer of
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33/144 coating is designed to exercise the ability to protect against high level sacrifice corrosion over a long period of time, it is preferable to allow the coating layer to contain these elements.
SI: FROM 0% TO LESS THAN 2.5%, SI SN [00217] Si is an element that has a small atomic size and a small amount of Si forms a solid interstitial solution in a thin MCSB phase. Since Si is a small element compared to atoms like Ca, Y, La, Ce, Bi and In, it does not serve as a substitutional element in a thin MCSB phase, but forms an interstitial solid solution and causes some changes in the crystalline structure of the fine MCSB phase (for example, an MggSn phase, MgCaSn phase or MggSns phase) while details are not confirmed. Although small changes in the crystalline structure cannot be captured by XRD, TEM or the like, it is often confirmed by ΕΡΜΑ that the Si contained in a small amount is identified in the same position as the thin MCSB phase.
[00218] In general, it is known that a small amount of Si has an effect of suppressing the growth of an Al-Fe alloy layer, and also has a confirmed effect of improving corrosion resistance. Si forms a solid interstitial solution in an Al-Fe alloy layer. The detailed description of the formation of an Al-Fe-Si or similar intermetallic compound phase in an AlFe alloy layer is as described above.
[00219] Si also forms a solid interstitial solution in a Ca-Zn-AI intermetallic compound phase described later. The effect of the Si solid solution on a Ca-Zn-AI intermetallic compound phase has not yet been confirmed. The amount of a phase of Ca-Zn-AI intermetallic compound containing Si tends to decrease relative Petition 870190071281, of 25/07/2019, p. 41/194
34/144 in a layer of Zn-AI-Mg alloy. In order to form a layer of Zn-AI-Mg alloy taking advantage of the phase characteristics of the Ca-Zn-AI intermetallic compound, it is preferable that the Si concentration is reduced.
[00220] Meanwhile, excess Si causes the solid solution structure of a thin MCSB phase to collapse, resulting in the formation of an intermetallic compound phase such as an MgzSi phase, in an alloy layer of Zn-AI-Mg. In addition, in a case where at least one of Ca, Y, La, Ce or is contained, an intermetallic compound phase such as a CazSi phase is formed.
[00221] In addition, Si forms a strong oxide film containing Si on the surface of a Zn-AI-Mg alloy layer. This Si-containing oxide film has a structure in which the ZnAI-Mg alloy layer is less likely to be eluted, resulting in reduced sacrificing corrosion protection. In particular, the reduction of the ability to protect against sacrificial corrosion in the initial corrosion phase before the collapse of an oxide film barrier containing Si has a significant impact.
[00222] In addition, the condition Si <Sn must be satisfied. In a case where the Si <Sn condition is satisfied, Si is contained in a thin MCSB phase in such a way that the reduction of the sacrificial corrosion protection capacity due to the contained Si can be avoided. However, in the case of Sn <Si, a needle-like crystalline MgzSi phase that differs from a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase is formed in large quantities, which makes it impossible to maintain the structure of a Zn phase including a thin MCSB phase. In addition, as an MgzSi phase promotes the formation of a ternary eutectic structure of Zn-AI-MgZn2, resistance to flat surface corrosion also
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35/144 deteriorates slightly. Therefore, it is preferable that a thin MCSB phase is formed in an amount greater than a
MgzSi, in a layer of a Zn-AI-Mg alloy.
[00223] Therefore, the Si concentration is defined as less than 2.5%. The Si concentration is preferably less than 0.5%, more preferably less than 0.3%, from the point of view of corrosion resistance to the flat surface and protection against sacrificial corrosion. In particular, it is preferable that the Si concentration is suppressed to less than 0.01% from the point of view of flat surface corrosion resistance and sacrificial corrosion protection capability.
[00224] However, when a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase are expected to be effective in improving the cracking and exfoliation prevention effects in a processed portion, the Si concentration is preferably 0.05% or more, more preferably 0.1% or more. The same also applies to the Ca concentration. The effects of the oxide film barrier in the presence of Si are limited, which are exhibited in the initial phase of corrosion. The ability to protect against sacrificial corrosion tends to be gradually improved over time.
[00225] Here, Si forms a solid solution in a thin MCSB phase, which is a solid interstitial solution in a thin MCSB phase. Thus, when Si forms a solid solution in a thin MCSB phase, the crystalline structure of the thin MCSB phase is distorted, which allows detection by XRD or similar. For this, it is preferable that Si is contained in the coating layer in a concentration of 0.05% or more. When the Si concentration is 0.05% or more, the Si contained in a thin MCSB phase is saturated. Even when Si is contained in a thin MCSB phase, the protective capacity
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36/144 against sacrificial corrosion is ensured against long term corrosion. In particular, it is preferable that Si is contained in a thin MCSB phase in terms of corrosion resistance in a processed portion. Likewise, it is also preferred in terms of the ability to protect against sacrificial corrosion (especially resistance to corrosion of the cut end surface).
[00226] Cr: from 0% to less than 0.25%, Ti: from 0% to less than 0.25%, Ni: from 0% to less than 0.25%, Co: from 0% to less than 0.25%, V: from 0% to less than 0.25%, Nb: from 0% to less than 0.25%, Cu: from 0% to less than 0.25%, Mn: from 0% to less than 0.25%, provided that 0 <Cr + Ti + Ni + Co + V + Nb + Cu + Mn <0.25 [00227] Sn in MgzSn is partially replaced by Cr, Ti, Ni, Co, V, Nb, Cu and Mn, as long as their content is small. In other words, a substituted MgzSn phase (thin MCSB phase) in which Sn is partially replaced by at least one of Cr, Ti, Ni, Co, V, Nb, Cu, or Mn is formed. The concentration of any of these elements must be less than the concentration of Sn. It is difficult to confirm an evident change in the ability to protect against sacrificial corrosion, which is observed in, for example, a substituted MgzSn phase (thin MCSB phase) including a substitution of Sn for Ca, Y, La, Ce, Bi or In. However, since Sn substituted as above it still binds to another Mg to form a thin MCSB phase. This allows the total amount of thin MCSB phase to increase. In addition, as it is possible to increase the Mg to be consumed to form a thin MCSB phase, the sacrificial corrosion protection effect is slightly increased, and the corrosion potential tends to shift to a relatively lower side.
[00228] Note that the amount of Sn that can be replaced is limited. In a case where the concentration of any of the elements becomes 0.25% or more or the total concentration of the same
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37/144 does not satisfy Cr + Ti + Ni + Co + V + Nb + Cu + Mn <0.25, an intermetallic compound phase composed mainly of the elements contained is formed instead of a thin MCSB phase. This makes it impossible to guarantee sufficient formation of a thin MCSB phase. For example, an intermetallic compound phase containing only one Mg element, such as an MgCu2 phase, is formed, which results in a reduced ability to protect against sacrificial corrosion. In addition, a coupling reaction occurs and the corrosion resistance deteriorates greatly. Processability also becomes poor.
[00229] Therefore, the concentrations of Cr, Ti, Ni, Co, V, Nb, Cu and Mn are defined as less than 0.25%, so that 0 Cr + Ti + Ni + Co + V + Nb + Cu + Mn <0.25 is satisfied.
FE: FROM 0% TO 5.0% [00230] In a case where a coating layer is formed by the melt coating method, Fe is contained at a certain concentration in a Zn-AI-Mg alloy layer and in an Al-Fe alloy layer.
[00231] It was confirmed that the Fe contained in a coating layer (particularly a layer of Zn-AI-Mg alloy) at a concentration of up to 5.0% does not disadvantageously influence the properties. In many cases, as Fe is contained mainly in an Al-Fe alloy layer, the concentration of Fe generally increases as the thickness of that layer increases.
[00232] Sr: from 0% to less than 0.5%, Sb: from 0% to less than 0.5%, Pb: from 0% to less than 0.5%, B: from 0% to less than 0.5%, since 0 Sr + Sb + Pb + B <0.5 [00233] It is not known whether Sr, Sb, Pb and B influence the formation of an intermetallic compound phase, such as a thin MCSB phase. Small amounts of these elements can form a solution
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38/144 solid in a Zn phase in a Zn-AI-Mg alloy layer and can also be detected in a thin MCSB phase. Therefore, they can play a role as a substitute. Although it is not particularly observed that these elements cause changes in properties, the elements can change the appearance of a coating layer, thus allowing a sequin pattern to be formed on the surface of the coating layer.
[00234] When the concentration of each of these elements is 0.5% or more, the element cannot form a solid solution in a Zn phase, although this does not affect the formation of a thin MCSB phase. As a result, several phases of intermetallic compound are formed, resulting in deterioration of processability and resistance to corrosion.
[00235] Therefore, the concentrations of Sr, Sb, Pb and B are defined as less than 0.5%. In addition, it is also necessary to satisfy Sr + Sb + Pb + B <0.5 as an index that prevents substitution for the formation of a thin MCSB phase while facilitating the formation of an intermetallic compound phase.
IMPURITIES [00236] Impurities are components that are contained in the starting materials or mixed in the production steps, with no intention of adding these components. For example, small amounts of different components of Fe are accidentally mixed as impurities in a coating layer due to atomic diffusion between a steel product (base metal) and a coating bath.
[00237] Next, the phases that constitute a layer of Zn-AI-Mg alloy will be described.
[00238] A Zn-AI-Mg alloy layer has a Zn phase. THE
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39/144 Zn phase has a thin MCSB phase (Mg-Sn intermetallic compound phase). In other words, the thin MCSB phase is contained (included) in the Zn phase.
[00239] The Zn-AI-Mg alloy layer may have an MgZn ₂ phase and Al phase. In addition, it is desirable that the Zn-AIMg alloy layer does not include a ternary eutectic structure of Zn-AI- MgZn ₂ or include only a small amount of a ternary eutectic structure of Zn-AI-MgZn ₂ .
[00240] Specifically, it is desirable that the ZnAI-Mg alloy layer has a structure that has an MgZn ₂ phase, Al phase, and a Zn phase including a thin MCSB phase. Regarding the quantities of the phases, it is desirable that the total quantities of the MgZn ₂ phase and the Al phase exceed the amount of the Zn phase including a thin MCSB phase in terms of area ratio. For example, it is desirable that the proportion of the MgZn ₂ phase and Al phase total area is 40% to 85% (preferably 50% to 75%), and the area proportion of the Zn phase including an MCSB phase fine is 3% to 35% (preferably 10% to 30%).
[00241] As each phase has a high level of corrosion resistance, an excellent structure for the corrosion resistance of the flat surface is formed. Although the thin MCSB phase portion is also easily eluted from the Zn phase including a thin MCSB phase, a corrosion product to be formed has the anti-rust effect, which eventually results in improved corrosion resistance. Thus, corrosion resistance comparable or superior to that of the Zn phase is acquired.
[00242] In a case where a coating layer contains Ca and Si, a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase can exist in a Zn- alloy layer AI-Mg. However, these phases of metallic compounds
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40/144 are finely dispersed in small amounts in the coating layer and do not constitute the main phase of the ZnAI-Mg alloy layer as in the thin MCSB phase.
[00243] Assuming that the amount of a Zn phase is responsible for half or more of the phase amount of a Zn-AI-Mg alloy layer (particularly when any of the conditions such as an Al concentration less than 20.0 %, a Mg concentration less than 5.0%, and a Sn concentration less than 3.0% is satisfied), it is likely that a thin ternary eutectic structure Zn-AI-MgZn ₂ is formed in the Zn alloy layer -AI-Mg. Since this ternary eutectic structure is susceptible to corrosion due to a coupling reaction, corrosion tends to progress more rapidly than the corrosion that occurs in a coating structure in which each crystal structure becomes a thick structure. In addition, when MgZn ₂ , which has a low processability, forms a ternary eutectic structure and is finely dispersed in a Zn-AI-Mg alloy layer, it is likely to become the source of the cracking. In particular, it is likely that white rust will form from numerous cracks that reach a base metal (steel product) in a processed or similar portion. Therefore, it is preferable to avoid the formation of this ternary eutectic structure as much as possible.
[00244] Here, most of the existing Zn-AI-Mg-coated steel products have a Zn-AI-Mg alloy layer that includes a ternary eutectic structure (Figure 1).
[00245] However, it becomes easier to avoid the formation of a ternary eutectic structure: 1) restricting the chemical composition of the coating layer according to the development to a certain range (particularly the Zn, Al and Mg concentrations) of in order to increase the phase amounts of the MgZn ₂ phase and the Al phase; 2) including elements that constitute a thin MCSB phase (Sn and
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41/144 other elements); and 3) to properly control the production conditions in the melt coating method. As a result, it is possible to eliminate or reduce this ternary eutectic structure.
[00246] Figure 2 is an SEM reflection electron image of a representative example of the coating layer according to the description. As shown in Figure 2, for example, a Zn phase, an Al phase, and an MgZn2 phase are present in a layer of a Zn-AI-Mg alloy. In addition, as Sn or similar is contained, the Zn phase includes a thin MCSB phase. As a result, the formation of a ternary eutectic structure of Zn-AI-MgZn2 is suppressed.
[00247] It is believed that this is because of the chemical composition of the coating layer according to the development caused by the formation of a Zn-AI-MgZn2 phase by the ternary eutectic reaction being altered to form a thin MCSB phase in the definitive reaction solidification. In addition, as a result of the loss or reduction of the ternary eutectic structure, sufficient processability is given even to a relatively hard coated steel product in which originally a large amount of an MgZn2 phase is formed with a large amount of Mg in one alloy layer of Zn-AI-Mg, which makes processing difficult.
[00248] Next, a thin MCSB phase (Mg-Sn intermetallic compound phase) will be described in detail.
[00249] A thin MCSB phase is a hard (grain) phase compared to a Zn phase, and is a soft phase compared to an MgZn2 phase. Normally, a hard intermetallic compound phase has a low plastic deformability. However, when it is finely deposited in a Zn phase, the deterioration of its plastic deformability is significantly reduced. Therefore, in a case where a thin MCSB phase is contained in a Zn phase, the hardness of the
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42/144 Zn phase increases while processability is unlikely to deteriorate.
[00250] However, when a thin MCSB phase increases, the phase amount of an MgZnz phase that has extremely low plastic deformability decreases slightly. Therefore, when a thin MCSB phase increases, the effects that lead to improved processability are exhibited.
[00251] These phenomena result in a coating layer with high hardness and excellent wear resistance, which also achieves processability even with high hardness.
[00252] Similar to the thin MCSB phase, a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase are also hard substances, but they are soft phases compared to the MgZng phase. Therefore, processing capacity is less likely to deteriorate even when these phases of intermetallic compounds are included.
[00253] Here, it is desirable that the hardness of a coating layer is at least 150 Hv at medium Vickers hardness. A coating layer that has an average Vickers hardness of 150 Hv or more is generally a coating layer that is harder than existing Zn-AI-Mg based coating layers and generally difficult to process. However, by controlling the structure of the Zn-AI-Mg alloy layer in the development, the coating layer processing, such as V-bending over a range of constant R values, is carried out and the processability equivalent to that of coated steel sheets based on existing Zn-AI-Mg can be achieved.
[00254] By allowing a thin MCSB phase to be contained in a Zn phase, it is possible to properly control the elution rate of a coating layer. When a thin MCSB phase
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43/144 is not incorporated in a Zn phase, the localized thin MCSB phase is eluted early, resulting in the immediate loss of the effects of the thin MCSB phase. In addition, as Zn is not eluted, a corrosion product suitable for corrosion protection is not formed. [00255] As a Zn phase containing a thin MCSB phase is formed, a ternary eutectic reaction of a Zn-AI-MgZn2 phase is not produced. Therefore, the ternary eutectic structure and the Zn phase containing a thin MCSB phase is unlikely to coexist. It has been experimentally found that while a Zn phase including a thin MCSB phase is present in a ZnAI-Mg alloy layer in an area fraction of 3% or more, particularly 5% or more, in a cross section of the ZnAI-Mg alloy of Zn-AI-Mg, means that a ternary eutectic structure was almost lost. In addition, as a result of the loss of a ternary eutectic structure, the corrosion resistance of the flat surface and processability have been improved. In addition, corrosion resistance on the flat surface can be exerted at a higher level than the commercially available Zn-AI-Mg coating, even with a high Mg content, making processability equivalent to that of the base coating possible of commercially available Zn-AI-Mg.
[00256] However, in order to maintain corrosion resistance on the flat surface, it is necessary to strictly comply with the chemical composition of the coating layer specified in the development and to suppress the formation of an intermetallic compound phase which causes extreme deterioration of the corrosion resistance with a flat surface other than a thin MCSB phase, a Ca-Zn-AI intermetallic compound phase, a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic phase. Once such an intermetallic compound phase is formed, the corrosion resistance of the flat surface can be deteriorated even in the presence of a Zn phase
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44/144 including a thin MCSB phase.
[00257] The loss of a ternary eutectic structure of Zn-AI-MgZn2 in the presence of a Zn phase including a thin MCSB phase is confirmed on the basis that the final solidification reaction is carried out not by the solidification of a Zn phase -AI-MgZn2 by a ternary eutectic reaction, but by the formation of a thin MCSB phase, according to the chemical component of the coating layer and the coating production method according to the development as mentioned above. To confirm whether or not a ternary eutectic structure is formed in a coating layer, it is more preferable to observe an optional sectional structure of an arbitrary coating layer for structural observation by SEM (for example, at an accelerating voltage of 15 kV or less , a 2 to 3A filament current, an emission current of 100 to 200 μΑ and a magnification of about 1,000 times).
[00258] Here, Figure 3 shows an example of a thin MCSB phase included in a Zn phase. As shown in Figure 3, a single thin MCSB phase is a very thin phase, and almost all thin MCSB phases do not reach a grain size of 1 pm and there is a lot in the Zn phase. This is due to the fact that a decrease in the solid solubility limit accompanying a decrease in the temperature of the Zn phase causes Mg, Ca, Sn, Bi and the like to be released during the solidification process of a coating layer, and a thin MCSB phase is formed as a result of the bonding of these elements. The thin MCSB phase deposited through this process is always contained in the Zn phase. In the melt coating method, it is empirically found that the thin MCSB phase often has a grain size of less than 1 pm and is deposited as spots.
[00259] Therefore, it is preferable that the thin MCSB phase contained in
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45/144 Zn phase has an average grain size of less than 1 pm. The lower limit of the average grain size of the fine MCSB phase is not particularly limited, but is, for example, 0.05 pm or more.
[00260] Note that when a thin MCSB phase is mainly formed and kept in a temperature range that allows atomic diffusion (around 150 Ό to 350 Ό) for a long period of time, an MCSB phase that has a Grain size of 1 pm or more is also observed. However, its location is always mainly in the Zn phase, merely indicating that the thin MCSB phases, which were finely dispersed in the initial state, grew and aggregated, and the grain size increased. Therefore, there is almost no influence on corrosion resistance on the flat surface and the like.
[00261] Here, resistance to flat surface corrosion and the ability to protect against sacrificial corrosion are contradicting each other and, in a case where an importance is placed on both properties, it is preferable that a thin MCSB phase is present . However, in a case where a coating layer to which importance is placed on the sacrificial corrosion protection ability, it is preferable to allow some MCSB phases to have a grain size of 1 pm or more to grow largely in a layer of Zn-AI-Mg.
[00262] Such MCSB phases, which have a grain size of 1 pm or more, correspond to a massive MCSB phase, described later.
[00263] The corrosion potential of a coating layer drops dramatically when a Zn phase containing a thin MCSB phase is present. Specifically, for example, the corrosion potential of the coating layer falls from the corrosion potential exhibited by a typical molten coating layer based on ZnPetição 870190071281, of 7/25/2019, p. 53/194
46/144
Al-Mg [-1.0 to -1.1 V (versus an Ag / AgCI reference electrode in 5% aqueous NaCI solution)] to around -1.5 V minimum, depending on the phase content of thin MCSB. Electrochemical measurement is an effective means of confirming the corrosion behavior at an early stage. When the presence of a thin MCSB phase causes a decrease in the corrosion potential of a coating layer, an element that has anti-corrosion effects (such as Mg or Ca) is dissolved earlier than a molten coating layer based on Zn -AI-Mg common, and covers, in particular, a base metal (steel product) and suppresses the formation of red rust in the base metal (steel product). The potential reduction allows an element that has anti-corrosion effects (such as Mg or Ca) to migrate over a long distance from its location. Therefore, an anti-corrosion effect on a cutting edge surface, which has been impossible to obtain with a conventional layer of molten coating based on Zn-AI-Mg, can be expected.
[00264] It is possible to confirm whether a thin MCSB phase is contained in a Zn phase by X-ray diffraction (XRD) using a Cu-Κα ray. Typically, the MgzSn diffraction peak in XRD is represented, for example, by JCPDS cards: PDF n ° 00-007-0274, n ° 00-006-0190 and n ° 00-002-1087. However, in a coating layer based on Zn-AI-Mg, the ideal diffraction peak for identifying a thin MCSB phase is a 22.8 ° diffraction peak that does not overlap with phase diffraction peaks. Zn phase, an MgZn2 phase, and an Al phase. In addition to the 22.8 ° peak, favorable diffraction peaks used to identify a fine MCSB phase are 23.3 ° and 24.2 ° diffraction peaks, which do not overlap with diffraction peaks of the other constituent phases of a coating layer and are convenient for identifying a thin MCSB phase.
[00265] In a case where Bi, In, Ca and the like are contained,
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47/144 in addition to Sn, an MgZn2 phase (or an Mg phase), which originally exists as a massive MgZn2 phase in a coating layer based on Zn-AI-Mg or exists as a ternary Zn eutectic structure -AI-MgZn2, decreases and is replaced by a thin MCSB phase. For example, the PDF No. 00-034-0457 is typical for identifying a MgZn2 phase and its peak stronger diffraction 41.3 ^it is an indicator of abundance. Generally, as the abundance of a thin MCSB phase increases, that peak intensity decreases.
[00266] Specifically, when based on an X-ray diffraction image of the coating layer surface, the image is measured using a Cu-Κα ray with an x-ray output at 40 kV and 150 mA, specific intensity I (thin MCSB phase) = {I (22.8 ° intensity (cps)) + I (23.3 ° intensity (cps)) + I (24.2 ° intensity (cps))} / 3 x I (background intensity at 20 ° (cps)) is 1.5 or more (more preferably, more than 3.0), it can be an index for the sufficient presence of Mg in the thin MCSB phase. The corrosion potential less than the corrosion potential (-1.0 to -1.1 V) shown by the existing coating layer based on Zn-AI-Mg is clearly observed. In other words, it is indicated that there is a diffraction peak distinguishable from the thin MCSB phase against the background. The presence of the thin MCSB phase makes it possible to clearly confirm the improvement of the corrosion resistance of sacrifice (especially the improvement of corrosion resistance on the surface of the cut end).
[00267] In recent years, there is software that can perform, for example, background removal as a method of calculating background intensity. From the diffraction peak intensity data obtained, graphs of 20 and intensity (cps) are generated to create an approximate line (straight line) of the flat portion confirmed at 15 ° to 25 °. Since the diffraction peak does not appear at 15 ° and 25 ° from
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48/144 of the surface of the coating layer according to the disclosure, when simply taking an average intensity value (cps) at 15 ° and 25 °, it gives a background intensity at 20 °. In a case where there is a possibility that some diffraction peaks overlap at 15 ° and 25 °, an average of the values at 15 ° (± 1 and 25 ° or an average of the values at 15 ° and 25 ° (± l ' ) is adopted.
[00268] When a thin MCSB phase is present in a Zn phase, it attracts ions like Cl- and OH- together with the pre-corrosion of the thin MCSB phase, resulting in corrosion of the surrounding areas. Therefore, a certain amount of a Zn phase, which is originally less soluble compared to Mg and Ca, is dissolved, and Zn is also eluted, as well as Mg and Ca, which also adds anti-rust effects to Zn. In addition, in the alloy layer of Zn-AI-Mg, Sn, Bi and the like, from which Mg and Ca are separated, they remain as single metals without migrating. This results in an environment in which there is a partially electrochemically superior portion in the Zn phase, and Zn around the portion is easily corroded. Mg and Ca are originally present as Mg (OH) 2 and Ca (OH) 2 in a base metal (steel product), and thus have high water solubility and are difficult to maintain stably on the surface of the coating and the metal base.
[00269] However, as Zn ions are eluted together with Mg and Ca, a corrosion product based on Zn is formed in an alkaline environment in the presence of Mg (OH) 2 and Ca (OH) 2. By incorporating Mg and Ca elements into the Zn-based corrosion product, it becomes possible to form a one-stage film of ZnMg-Ca intermetallic compound that protects a base metal in a short period of time.
[00270] Therefore, a structure in which a thin MCSB phase is included in a Zn phase has the capacity to protect against high level sacrifice corrosion and its corrosion content increases by
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49/144 compared to a structure in which a thin MCSB phase is simply included (in other words, a structure in which a thin MCSB phase is formed outside a Zn phase). However, as a highly corrosion-resistant film is formed immediately, corrosion resistance is greatly improved in many cases. By controlling the phase quantities of the thin MCSB phase and the Zn phase, the effects (the elution range and the corrosion protection period) can be controlled.
[00271] In particular, when a Zn phase containing a thin MCSB phase is present with an area fraction of 3% or more (preferably 10% or more) (with respect to a cross section of a Zn alloy layer -AI-Mg), elements eluted from a coating layer at an early stage have an increased tendency to form an anti-rust film immediately. Therefore, the sacrificial corrosion protection capability (particularly the corrosion resistance of the cut end surface) is further improved.
[00272] Meanwhile, in a Zn phase containing a thin MCSB phase, when a thin MCSB phase (in other words, an Mg-Sn intermetallic compound phase that has a grain size of less than 1 pm) present with a fraction of area for a Zn phase containing a thin MCSB phase) of 10% to 50% (preferably 15% to 35%), the elements eluted from a coating layer in an initial phase have an increased tendency to form an anti-rust film immediately. Therefore, the ability to protect against sacrificial corrosion (particularly the corrosion resistance of the cut end surface) is further improved.
[00273] Therefore, in a cross section of a layer of Zn-AI-Mg alloy, the area fraction of a thin MCSB phase (in orPetition 870190071281, of 7/25/2019, p. 57/194
50/144 In other words, a phase of Mg-Sn intermetallic compound having a grain size of 1 pm) relative to a Zn phase containing a thin MCSB phase is preferably 10% to 50%.
[00274] Next, the effect containing Ca to effectively improve the ability to protect against sacrificial corrosion will be described.
[00275] When Ca is contained in a layer of ZnAI-Mg alloy, Mg in MggSn is partially replaced by Ca. For example, when the Ca concentration is from 0.05% to 3.00%, the formation of a MgCaSn phase or similar, which is a substituted MggSn phase (thin MCSB phase) is observed. As the amount of an MggSn phase increases, the amount of an MggSn phase that is allowed to be changed to an MgCaSn phase increases. The crystalline structure of an unsubstituted MggSn is changed to convert to MggSns. As the amount of MggSn increases, MggSns also increases.
[00276] In other words, when the Ca concentration is from 0.05% to 3.00%, an MgCaSn phase and an MggSns phase are contained in a Zn phase as a thin MCSB phase.
[00277] As the formation of an MgCaSn phase and the transformation to a progression of the MggSns phase, the ability to protect against sacrificial corrosion of a coating layer is improved and the ability to protect against sacrifice corrosion in the long run term is improved. An incorporation index of all Ca contained in MggSn and an index for the transformation of an MggSns phase are required. For the detection of a thin MCSB phase in which Ca is incorporated, it is preferable to confirm that Ca is originally detected in a position identical to the position of Mg by TEM or ΕΡΜΑ. However, it can be confirmed based on an X-ray diffraction image of the surface of a coating layer
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51/144 measurement subjected to measurement using a Cu-Κα ray with an X-ray output at 40 kV and 150 mA.
[00278] Typically, the XRD diffraction peak of Mg ₂ Sn can be applied to a coating layer based on Zn-AI-Mg, and diffraction peaks at 22.8 ° 26.3 ° and 37.6 ° are Mg ₂ -Sn specific differential peaks which are representative diffraction peaks used for detection. Meanwhile, for example, MgCaSn is represented by the JCPDS card: n ° 01-072-5710, MggSns is represented by the JCPDS card: n ° 01-073-8010. A diffraction peak at 23.3 ° is a diffraction peak detected in Mg ₂ Sn, MgCaSn or MggSns, regardless of the presence of Ca.
[00279] Here, the diffraction peaks at 22.8 ° and 26.3 ° become smaller as the Ca concentration increases, and the peaks become difficult to detect after replacing the Ca. The same trend is also observed for a diffraction peak at 37.6 °. However, as the peak is surrounded by large peaks of difference, it is not suitable for identification.
[00280] The degree of Ca substitution, which means that the quantities of an MgCaSn phase and a formed MggSns phase, can be measured using intensities for these degrees as indices. Specifically, when the following formula: specific intensity I (MgCaSn + MggSns) = {I (22.8 ° intensity (cps)) + I (26.3 ° intensity (cps))} / l (23.3 ° intensity (cps)) produces less than 0.3 (preferably less than 0.1), and I (23.3 ° intensity (cps)) is 500 cps or more, this means that a phase of Mg ₂ Sn (thin MCSB phase) exists in a layer of a Zn-AI-Mg alloy, Ca substitution occurs in almost all Mg positions in the existing Mg ₂ Sn and, therefore, the main phase consists of the MgCaSn and in the MggSns phase.
[00281] In a case where I (23.3 ° of intensity (cps)) is less
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52/144 than 500 cps, since the amount of the MggSn phase (thin MCSB phase) originally found in the Zn-AI-Mg alloy layer is not sufficient, it is preferable that the specific intensity I (MgCaSn +
MggSns) is set to 0.3 or more.
[00282] The properties of an MggSn phase (thin MCSB phase) by Ca substitution are altered, as described below. When Ca is incorporated into an MggSn phase so that an MgCaSn phase is formed, the amount of Mg eluted can be adequately suppressed without changing the sacrificing corrosion protection capacity (corrosion potential) of the MggSn phase. As a result, effects of a high level of corrosion protection can be achieved over a long period of time. Similar effects are also obtained for an MggSns phase. These effects can be confirmed by various corrosion tests and the like, as well as by electrochemical measurement.
[00283] The effects of including Y, Ce, La, Bi and In other than Ca can be confirmed by the same method. In addition, although a small amount of a Sn phase can be detected around an MgCaSn phase and an MggSns phase due to changes in the crystalline structure, since the amount is small, changes in properties are not significant and can be ignored.
[00284] Next, the effects containing Si will be described.
[00285] When Si is contained, Si forms a solid interstitial solution in a thin MCSB phase as described above, which makes the resulting crystalline structure more complicated. At that time, the preferred orientation of the fine MCSB phase crystal is easily changed. So, for example, in a case where there is the MgCaSn phase and the MggSns phase corresponding to the thin MCSB phase, there is an exceptional coating layer that can achieve the effect of
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53/144 protection against sacrificial corrosion, although the assessment indices described above are not satisfied.
[00286] For example, in a case where high concentration Ca, Si and Mg are contained (specifically a case where a Mg concentration ranges from more than 4.0% to less than 12.5%, a concentration of Ca from 0.05% to 3.00% and a Si concentration of 0.01% to 2.5% are satisfied), an exceptional coating layer, which does not correspond to some of the indices described above appears. Even in such a coating layer, when Ca, Si and Mg satisfy the chemical components described above, it is possible to define the effect of allowing a thin MCSB phase to contain Si, establishing a new index for the obtained XRD intensity.
[00287] Here, the specific intensity described above I (thin MCSB phase) = {I (22.8 ° intensity (ops)) + I (2 3.3 ° intensity (ops)) + I (24, 2 ° intensity (cps))} / 3 χ I (20 ° background intensity (cps)) is 1.5 or more, and between diffraction peaks that appear at 23.0 ° to 23.46 °, a diffraction peak with the strongest intensity appears between 23.36 ° and 23.46 ° which serve as preconditions. Even in a case where the specific intensity described above I (MgCaSn + MggSns) is not satisfied, high-level effects of sacrificial corrosion protection can be confirmed. In other words, in a case where the angle with the strongest intensity (20) of a diffraction peak derived from the thin MCSB phase containing Si (diffraction peak with origin at 23.3 ^ appears and between 23.36 ° at 23.46 ° the high-level effects of protection against sacrificial corrosion can be confirmed.
[00288] For example, in a case where an MgCaSn phase and an MgCaSn phase, which usually correspond to a thin MCSB phase, do not contain Si, the strongest intensity of the diffraction peak originating at 23.3 ° appears between 23.25 ° and 23.3 °. Meantime,
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54/144 in a case where the MgCaSn phase and the MgCaSn phase contain Si, as a crystalline network made of the MgCaSn phase and the MgCaSn phase is distorted, the strongest intensity appears between 23.36 ° to 23 °, 46 °. This thin MCSB phase containing Si (the MgCaSn phase containing Si and the MgCaSn phase containing Si) has similar effects to the effects of the Si-free MgCaSn phase and the Si-free MggSns phase. In other words, the rate of Corrosion of the fine MCSB phase is optimized in terms of long-term sacrifice corrosion protection capability.
[00289] Si is likely to bind to a Ca-AI intermetallic compound phase and to an MgAl intermetallic compound phase. The inclusion of such phases of the intermetallic compound bound to Si allows to confer special properties.
[00290] Specifically, when Ca and Sn are contained in a Ca concentration of 0.05% to 3.00% and a Si concentration of 0.01% to 2.5%, respectively, it is possible to confirm the formation of at least one phase selected from the group consisting of a phase of Ca-AI-Si intermetallic compound and a phase of Mg-AI-Si intermetallic compound in a Zn-AI-Mg alloy layer by SEM or similar.
[00291] The average grain size of a Ca-AI-Si intermetallic compound phase and an Mg-AISi intermetallic compound phase is 1 pm or more. An average grain size of 1 pm or more is sufficient grain size to allow a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase to be identified by TEM. Therefore, there is no lower limit threshold for the average grain size of a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase in terms of special properties. However, although the upper limit of the average grain size of an intermetallic compound phase, Petition 870190071281, of 7/25/2019, p. 62/194
55/144 lytic of Ca-AI-Si and a phase of Mg-AI-Si intermetallic compound is not particularly limited, it is set to, for example, 30 pm or less.
[00292] The growth behavior or the location of a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase vary according to the production method or the chemical composition of a layer of coating. In a case where quenching is carried out during the solidification of a coating layer, many fine phases of Ca-AI-Si intermetallic compound and fine phases of Mg-AI-Si intermetallic compound with small grain sizes are formed. However, in a case where slow cooling takes place, the grain size increases and the number of fine phases of the intermetallic compound decreases.
[00293] In addition, a Ca-AISi intermetallic compound phase is generally in the form of a needle or rod in many cases. A phase of Mg-AI-Si intermetallic compound is in amorphous or spherical form in many cases. However, there are some exceptions, and even a Ca-AI-Si intermetallic compound phase can become amorphous. However, even a phase of Mg-AI-Si intermetallic compound can be in the shape of a rod or needle. [00294] In a case where a phase of Ca-AI-Si intermetallic compound and a phase of Mg-AI-Si intermetallic compound are in the form of a needle or rod, the length of the longest line (such as a diagonal line ) is determined as the grain size of the Ca-AI-Si intermetallic compound phase and the Mg-AI-Si intermetallic compound phase. In a case where a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase are in amorphous or spherical form other than a needle or stick-like shape, the diameter of the circle of equivalent area is determined to be the grain size of the compos phase
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56/144 intermetallic content of Ca-AI-Si and the phase of the intermetallic compound of
Mg-AI-Si.
[00295] Here, Figure 8 shows an electronic SEM reflection image of a cross section of an example of the coating layer according to the description, which is a cross section of a coating layer containing Ca and Sn at a concentration of Ca from 0.05% to 3.00% and a Si concentration of 0.01% to 2.5%, respectively (SEM reflection electron image of an oblique cross section of a coating layer with an inclination of 10 ^.
[00296] Figure 10 shows an enlarged image (SEM electronic reflection image) of the coating layer structure in the white frame in Figure 8.
[00297] As shown in Figures 8 and 9, when Ca and Sn are contained in a Ca concentration of 0.05% to 3.00% and a Si concentration of 0.01% to 2.5%, respectively, for example, a granular or amorphous Mg-AI-Si intermetallic compound phase and a needle-like Ca-AI-Si intermetallic compound phase are present in a coating layer.
[00298] In addition, Figure 10 shows an enlarged image (TEM image) of the vicinity of the interface between the cladding layer and the base metal (steel product) shown in Figure 8.
[00299] Figure 11A shows an electron beam diffraction image of the amorphous intermetallic compound 13 phase in Figure 10, and Figure 11B shows an EDS analysis spectrum of the amorphous intermetallic compound 13 phase in Figure 10.
[00300] Figure 12A shows an electron beam diffraction image of the needle-like intermetallic compound phase 14 in Figure 10, and Figure 11B shows an EDS analysis spectrum of the needle-like intermetallic compound phase 14 in Figure 10.
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57/144 [00301] In Figure 10, the phase of the amorphous intermetallic compound 13 is detected as containing Mg, Al and Si as shown in the electron beam diffraction image (Figure 11A) and the EDS analysis spectrum (Figure 11B) (Zn is derived from the bottom and Cu is derived from the analysis method). Therefore, the phase of the amorphous intermetallic compound 13 is identified as a phase of the compound Mg-AI-Si (phase of MgAISi as an example).
[00302] In Figure 10, the phase of the needle-type intermetallic compound 14 is detected as containing Ca, Al and Si, as shown in the electron beam diffraction image 14A and the EDS analysis spectrum (Figure 12B) (Zn is derived bottom, and Cu is derived from the analysis method). Therefore, the needle-like intermetallic compound phase 14 is identified as a phase of the Ca-AI-Si compound.
[00303] As described above, a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase cannot generally be combined as an intermetallic compound phase discovered in the past, as shown in Figures 11A and 12A even in a case in which they are analyzed based on electron beam diffraction images by TEM or similar. However, as shown in Figures 11B and 12B, as Ca, Al and Si or Mg, Al and Si are detected simultaneously by EDS analysis, a Ca-AI-Si intermetallic compound phase and an Mg-AI intermetallic compound phase. -Si can be identified as an intermetallic compound phase containing such elements.
[00304] In other words, a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase can be distinguished based on an electron beam diffraction image by TEM or similar or by EDS analysis. In a case where Ni is contained in a coating layer, in addition to Zn, elements such as Zn and Ni can also be detected simultaneously
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58/144 mind.
[00305] A Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase are preferably formed in comparison to a thin MCSB phase, which can cause the thin MCSB phase to decrease, and it can also cause Ca, Y, La, or Ce to be released from the thin MCSB phase. However, in a case where the Ca concentration is sufficient, for example, 0.05% or more, there is no need to pay special attention.
[00306] A Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic phase are relatively hard and have low ductility. When these intermetallic compound phases that have an average grain size of 1 pm or more exist in large quantities in a Zn-AI-Mg alloy layer, this causes a coating layer to be finely ground during processing. For example, a coating layer is finely broken by conducting a T-bend test or similar, compared to a case where these phases of intermetallic compounds are not present on the outside (pull side) of a processed portion (for example, Ca and Si are not contained). In general, as an alloy-based coating layer has poor ductility compared to a base metal (steel product), many exposed portions of a base metal (steel product) appear under cracks in a coating layer .
[00307] When the width of a single crack is large, the coating layer is excessively protected against sacrificial corrosion. The sacrificial corrosion protection capacity is reduced and the corrosion resistance of the processed portion deteriorates in a processed portion until an exposed crack-induced exposed portion of the base metal is covered with rust.
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59/144 [00308] However, when the width of a single crack is small (meaning that a coating layer is finely cracked), adequate sacrificial corrosion protection is obtained. Therefore, adequate sacrificial corrosion protection capability is also achieved in a processed portion, resulting in suppressed degradation of the processed portion's corrosion resistance.
[00309] In other words, the effect of improving corrosion resistance during processing can be obtained in the presence of a Ca-AI-Si intermetallic compound phase that has an average size of 1 pm or more and a compound phase intermetallic MgAl-Si having an average grain size of 1 pm or more.
[00310] As described above, from the point of view of improving the corrosion resistance of the processed portion, it is preferable that at least one is selected from the group consisting of a phase of Ca-AI-Si intermetallic compound having an average grain size 1 pm or more and one The Mg-AI-Si intermetallic compound phase, with an average grain size of 1 pm or more, is present in a Zn-AI-Mg alloy layer.
[00311] In addition, from the point of view of effectively improving the corrosion resistance of the processed portion, the fraction of area (fraction of area in relation to a cross section of a layer of Zn-AI-Mg alloy) of each phase of Ca-AI-Si intermetallic compound which has a grain size of 1 pm or more and a phase of Mg-AI-Si intermetallic compound which has a grain size of 1 pm or more is preferably more than 0 % less than 1%. Each of a Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase does not represent a large fraction of area (1% or more) in the chemical composition of the coating layer according to revelation.
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60/144 [00312] In relation to the T-bending test, in general, processing is intensified in 0T curvature (full bend, 180 degree bending) than in the 4T bend or similar (a space with a thickness of four sheets is left inside the fold), and crack-induced degradation of the corrosion resistance of the processed portion is likely to be observed in curvature 0T. When at least one of a Ca-AI-Si intermetallic compound phase or an Mg-AI-Si intermetallic compound phase is finely dispersed in a Zn-AI-Mg alloy layer, a coating layer is finely broken in any processing situation. Therefore, the alloy layer is less susceptible to the strength of a processed portion.
[00313] Next, a phase of Ca-Zn-AI intermetallic compound will be described.
[00314] In a case where the Ca concentration is from 0.05% to 3.00% (preferably from 0.10% to 1.00%), there is enough Ca for Sn, indicating that there is no position for the substitution of Mg in a thin MCSB phase and thus Ca can bind to Zn and Al in a layer of Zn-AI-Mg alloy. This is due to the fact that Ca originally tends to bind to Zn, in order to form a phase of Ca-Zn intermetallic compound (such as the CaZn2 phase, the CaZns phase or the CaZnn phase). In a case where the Ca concentration is high, since segregation is highly likely to occur, a phase of intermetallic compound in which binding occurs is not limited to any of the above types. In the case of the chemical composition according to the disclosure, a phase of Ca-Zn-AI intermetallic compound is formed, in which the Zn in a metallic phase of Ca-Zn is replaced by Al (hereinafter also called CZA phase ).
[00315] A CZA phase has little effect in providing sacrificial corrosion protection capability. However, since a CZA phase is contained in a Zn-AI-Mg alloy layer, the
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61/144 flat surface corrosion resistance is improved. Additionally, in a case where a CZA phase is deposited, the hardness of a coating layer increases slightly due to the fact that a soft Al phase decreases, resulting in improved wear resistance. In general, as the corrosion resistance of the flat surface is improved, the elution of elements constituting a coating layer having anti-rust effects is reduced, resulting in a reduction of the protective effects against sacrificial corrosion. However, since a CZA phase has no influence on the elution of a thin MCSB phase, it does not reduce the sacrificial corrosion protection capacity.
[00316] In particular, when a CZA phase that has a grain size of 1 pm or more is present in a cross section of a Zn-AI-Mg alloy layer with an area fraction of 5% or more (preferably 10% or more) in relation to the cross section of the Zn-AI-Mg alloy layer, the resistance to flat surface corrosion is improved. For example, the amount of white rust formed in a salt spray test (SST), which is an accelerated corrosion test, decreases.
[00317] However, when the area fraction of a CZA phase that has a grain size of 1 pm or more exceeds 5.0%, conversely, the corrosion resistance tends to decrease. In addition, since a CZA phase is originally a very hard phase, the Vickers hardness of a coating layer increases markedly and processability tends to decrease. Therefore, the lower limit value of the fraction of the area of a CZA phase that has a grain size of 1 pm or more is preferably 5.0% or less, more preferably 2.0% or less.
[00318] The upper limit of the grain size of such a CZA phase is not limited, but it is, for example, 10 pm or less.
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62/144 [00319] A CZA phase can generally have a different shape (such as a cubic, needle-shaped, rod-shaped or amorphous shape) in a Zn-AI-Mg alloy layer. When a CZA phase is formed in a square, needle or stem, the length of the longest line (such as a diagonal line) is determined to be the grain size of a Ca-ZnAl intermetallic compound phase. In a case where a CZA phase has an amorphous shape other than a square, needle or rod shape, the diameter of the circle with equivalent area is determined to be the grain size of the CZA phase.
[00320] It is preferable to confirm the presence of a CZA phase by TEM. In addition, the presence of a CZA phase can also be confirmed by confirming Al which is not detected in a position identical to the Zn position of a Ca-Zn intermetallic compound phase by ΕΡΜΑ. In addition, the presence of a CZA phase can be confirmed by X-ray diffraction (XRD) using a Cu-Ka ray.
[00321] Normally, the CZA diffraction peaks in XRD are represented by the JCPDS cards: PDF n ° 00-028-02 57 for CaZn 2 and PDF n ° 00-010-0239 for CaZns. However, differential peaks derived from CZA also appear at 33.3 ° and 35.0 °.
[00322] Furthermore, in a case where Ca is sufficient for Sn, Mg2Sn is substantially altered to have the crystalline structure of MggSn 5 as described above. Therefore, it is possible to adopt, as an indicator for the presence of a CZA phase, the detection of the difference peak originating from 10.4 “confirmed only in the presence of MggSns.
[00323] The intensities of these angles can be used as indices to measure the degree of formation of a CZA phase in relation to a thin MCSB phase. It was revealed that the area fraction of the
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63/144 CZA phase is 5% or more when based on an X-ray diffraction image of the coating layer surface after measurement using a Cu-Κα ray with an X-ray output at 40 kV and 150 mA, the value obtained by the following Formula is 0.5 or more: specific intensity I (CaZnAI) = {I (10.4 ° intensity (cps)) + I (33.3 ° intensity (cps) + I (35.0 ° intensity)} / l (23.3 ° intensity (cps)).
[00324] Next, an MCSB phase (massive MCSB phase) that has a grain size of 1 mm or more will be described.
[00325] It is desirable that an MCSB phase that has a grain size of 1 pm or more is present in an alloy layer of Zn-AI-Mg. For example, for a steel or similar product including many exposed parts of a base metal, it is possible to instantly suppress corrosion of an exposed part of a base metal (steel product) by improving the sacrificial corrosion protection ability in rather than flat surface corrosion resistance. Therefore, it is preferable to allow one MCSB phase to partially form a large mass, rather than allowing the entire MCSB phase to be finely deposited.
[00326] When a huge phase of MCSB exists, an excellent ability to protect against sacrificial corrosion can be ensured. Although the upper limit of the grain size of a massive MCSB phase is not particularly limited, it is adjusted to, for example, 20 pm or less.
[00327] In a case where the concentration of Sn is strictly controlled (specifically when the Sn content is 3.00% to 20.00% by weight and Sn and Zn represent the element content, the control is done to satisfy the following formula: 0.05 <Sn / Zn), the concentration of Sn contained in a layer of Zn-AI-Mg alloy increases relatively. Consequently, a massive MCSB phase is Petition 870190071281, of 7/25/2019, p. 71/194
64/144 positioned in a Zn-AI-Mg alloy layer (see Figures 4 and 5). At
Figures 4 and 5 show that a polygonal MCSB phase that has a grain size of 1 pm or more is precipitated.
[00328] A massive MCSB phase is larger than an MCSB phase that has a grain size of less than 1 pm, but often exists in a Zn phase or adjacent to a Zn phase (see Figures 4 and 5) . Therefore, a massive MCSB phase is assumed to be formed by aggregation in the precipitation process.
[00329] In particular, in order to prolong the antirust period of a base metal (steel product) or similar with an excellent ability to protect against sacrificial corrosion, it is preferable that a massive MCSB phase is present in a cross section of a Zn-AI-Mg alloy layer with an area fraction of 3% or more (preferably 5% or more) relative to the cross section of the Zn-AI-Mg alloy layer.
[00330] Note that, although the upper limit of the fraction of the massive MCSB phase area is not particularly limited, it is defined as, for example, 20% or less.
[00331] Next, a eutectoid structure (hereinafter also referred to as a thin Zn-AI eutectoid structure) that has a lamellar spacing of less than 300 nm, which is composed of a Zn phase and an Al phase will be described.
[00332] The chemical composition of the coating layer according to the development contains several alloy components, resulting in high hardness as described above. Processability in the constant value range of R can guarantee processability equal to the existing Zn-AIMg without spraying. However, for example, in the case of intensified processing, such as intentional, for which a hard coating layer is disadvantageous, the processability becomes slightly less.
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65/144 [00333] Note that even in the case of the chemical composition of the coating layer according to the disclosure, it is possible to obtain a coating layer rich in plastic deformability, changing the form of existence of a Zn phase and a Al in a layer of Zn-AI-Mg alloy by a specific manufacturing method. In other words, the coating layer can include a processability-rich phase.
[00334] Specifically, in order to allow the coating layer to contain a processability-rich phase, it is desirable that the coating layer has a structure in which an Al phase showing dendrite-like growth is lost or reduced as a eutectoid structure of thin Zn-AI increases (see Figures 6 and 7).
[00335] The thin eutectoid structure of Zn-AI has a lamellar structure (also known as a labyrinth structure or fine three-dimensional mesh structure) and is a eutectoid structure in which a Zn phase and an Al phase are alternately codeposited in one lamellar spacing less than 300 nm (see Figure 7).
[00336] When a thin eutectoid structure of Zn-AI is present in a cross section of a layer of Zn-AI-Mg alloy with an area fraction of 10% or more (preferably 15% or more) in relation to the section cross-section of the Zn-AI-Mg alloy layer, a coating layer has improved processing capacity and has resistance against spraying, exfoliation or the like after intensified processing, such as folding / unfolding.
[00337] It is therefore desirable that the thin Zn-AI eutectoid structure is present with an area fraction of 10% or more (preferably 15% or more) in relation to the cross section of the Zn-AI- alloy layer. Mg.
[00338] Note that, although the upper limit of the fraction of the area of
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66/144 eutectoid Zn-AI fine structure is not particularly limited, it is defined, for example, at 25% or less.
[00339] Next, a ternary eutectic structure of Zn-AIMgZn2 will be described below.
[00340] A ternary eutectic structure includes an Al phase, a Zn phase and an MgZn phase. The shape of each phase is amorphous due to the fact that its size changes according to the composition of the component. However, since the eutectic structure is transformed at isothermal temperatures and the migration of elements during solidification is suppressed, the individual phases form an intricate shape, and normally each phase is finely deposited (see Figure 14).
[00341] Normally, the respective phases often form a configuration in which one phase of Zn is larger and that forms an island, one phase of MgZn is the second largest and fills a gap between the phases of Zn, and a phase of Al is dispersed as a stain in an MgZn2 phase. A constituent phase that does not change while being deposited in the form of an island can be an MgZn2 phase, or it can be an Al phase or an MgZn2 phase, depending on the composition of the component. The positional relationship depends on changes in the components immediately before solidification.
[00342] A method for specifying a ternary eutectic structure will be described later.
[00343] The presence of such a ternary eutectic structure composed of thin phases results in the deterioration of resistance to flat surface corrosion and processability as mentioned above.
[00344] Therefore, the area fraction of a ternary eutectic structure of Zn-AI-MgZn2 is defined as from 0% to 5%, preferably from 0% to 2%. The area fraction of a eutectic structure has
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67/144 nary is more preferably 0%.
[00345] Next, an example of a production method for the coated steel product of the development will be described below.
[00346] The coated steel product of the development is obtained by forming a coating layer on the surface (one side or both sides) of a coating base material (such as a coating base plate) by the coating method Fusion.
[00347] A pure metal or alloy of a specific component composition prepared in a vacuum melting furnace or similar is used for a coating bath, mixed in a certain amount to achieve the target composition and dissolved in the air. To perform the melt coating method, an operating temperature above the melting point is normally required.
[00348] In the preparation of the coated steel product, for example, after rolling by the Sendzimir method, a hydrogen reduced steel product is directly immersed in the coating bath at 800 Ό in a non-oxidizing environment. Sufficient immersion time is usually 0.5 seconds at most, while immersion also affects the thickness of an Al-Fe alloy layer as a coating layer. After immersion, the amount of N2 gas spray adhesive is adjusted.
[00349] In the production method of the coated steel product of the development, temperature control is essential for the temperature of the coating bath and the solidification process for the control of the structure.
[00350] In order to allow a Zn phase to contain a thin MCSB phase, it is necessary to carry out temperature control for the control of the proper order of phase solidification, and also for the formation and disappearance of a dendrite structure in an
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68/144 Al phase, formation of a fine structure in a Zn phase and an Al phase.
[00351] For example, it is difficult to deduce the solidification process of a quaternary structure or higher, including Ca and the like, as well as Zn, Al, Mg and Sn based on the phase diagram, and it is necessary to interpret the solidification according to each experiment. The melting point of a thin MCSB phase is about 775 Ό (melting point of Mg ₂ Sn as the main component), the melting point of Al is 660 Ό, the melting point of MgZn ₂ is about 550 O, and the melting point of Zn is 420 Ό. In addition, the melting point of a CZA phase is 700 Ό to 750 Ό. Although the melting point of a Ca-AI-Si intermetallic compound phase and the Mg-AI-Si intermetallic compound phase cannot be clearly defined, it is estimated that each melting point is around 700 Ό a 1000 Ό.
[00352] Those with high melting points generally tend to be deposited in the initial stage of the solidification process, although this depends on the composition. In particular, when the Mg concentration is in the range of 5% or more and the Sn concentration is in the range of 0.5% or more, a thin MCSB phase is more likely to be deposited, and is deposited earlier ( high temperatures) in the solidification process. The cooling carried out in such a solidification process results in the formation of a liquid phase in which a thin MCSB phase is not sufficiently contained in a Zn phase and the final solidification portion becomes a liquid phase containing Zn, Al and Mg. Eventually, a ternary eutectic structure of Zn-AI-MgZn ₂ that degrades the corrosion resistance of the flat surface and processability is also formed.
[00353] Here, a thin MCSB phase that is not contained in a Zn phase is located and coarsely present on the surface of the coating layer or close to the Al-Fe alloy layer. This is
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69/144 particularly likely to occur when the Sn concentration is 3% or more. The reason is that the growth rate of an accurate MCSB phase is extremely high. A thin MCSB phase located on the surface of the coating layer or close to the Al-Fe alloy layer is easily dissolved during corrosion. Therefore, coating exfoliation and the like tend to occur in the corrosion process, which is an incomprehensible coating property. In addition, an Al phase and a thin MCSB phase are likely to be deposited simultaneously at a Sn concentration of up to 3%, and the thin MCSB phases tend to be surrounded by the Al phase. Therefore, in a case where a thin MCSB phase is hardly soluble in a coating layer or a case where Sn cannot reach a sufficiently high level of corrosion protection capacity, may result in a case where the concentration of Sn in the coating layer becomes if extremely low so that a ternary eutectic structure of Zn-AI-MgZn2 is likely to be formed.
[00354] In other words, in order to allow a thin MCSB phase to function properly, it is desirable to allow a thin MCSB phase to be finely dispersed in a Zn phase.
[00355] It has been revealed in terms of the chemical composition of the coating layer according to the disclosure that, for example, when the coating bath temperature is defined as a coating production condition for the coating bath with melting point + 20 Ό, and slow cooling is performed from the melting point of the coating bath to 150 Ό at a cooling rate of 5 Ό to 10 Q / s, a thin MCSB phase is often deposited as a coarse primary crystal, which prevents the thin MCSB phase from being deposited in a Zn phase. In other words, the state described above in which a thin MCSB phase is located or
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70/144 surrounded by an Al phase is likely to be realized. This means that a thin MCSB phase is less likely to be deposited in a Zn phase in production under general coating production conditions.
[00356] Furthermore, the temperature of the coating bath causes a certain change in the process of solidification of the coating and is likely to cause a change in the formation of the structure. It is preferable that, in relation to the coating production conditions, production is carried out under the recommended conditions. However, since a coating structure is formed based on the combination of a chemical composition, transformation point (temperature) and a plurality of temperature histories, it is possible to form a structure similar to a structure recommended by procedures other than the procedures recommended production rates below provided the chemical composition of a coating layer has been determined.
[00357] In addition, also under preferred coating production conditions for coating production (for example, 1) the case of coating welding with an upper roller, 2) the case of tempering using mist cooling to prevent failure of sequins during the solidification of a coating layer, or) the case of cooling the melting point of the coating bath to 150 Ό at a cooling rate of 30 Ό / s or more after the coating treatment at a temperature of the coating bath coating (melting point of the coating bath + 20 Ό)), an Al phase containing alloy elements, a solid saturated Zn solution of an Al phase (Al phase containing a large Zn phase), a MgZn2 phase which has poor plastic deformability, and the like are formed in large quantities in a layer of Zn-AI-Mg alloy and a thin MCSB phase is not deposited in a
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71/144 Zn phase, resulting in a coating layer with poor processability. This means that, although the temperature process conditions described above correspond to a temperature process that is relatively often considered for melt coating, a thin MCSB phase is unlikely to be deposited in a Zn phase, even by this temperature.
[00358] This is a general solidification phenomenon that, for example, elements that have higher melting points are deposited earlier, or the equilibrium separation does not take enough time. Therefore, in order to allow a thin MCSB phase to be deposited in a Zn phase, it is necessary to allow an Al phase and an MgZn2 phase to be deposited in advance, decrease the concentration of Al in a melt, increase the concentrations of Zn, Mg and Sn, fuse Mg and Sn into a fused Zn phase (fuse other elements like Ca, in addition to Mg and Sn, according to purpose), and allow each element to be slowly released along with a decrease in dissolution limit due to a decrease in temperature, thus allowing the thin MCSB phase to be deposited in the Zn phase. By adopting this solidification process, it is possible to replace a ternary eutectic structure of Zn-AI-MgZn2, which is originally formed as the final solidification portion of a coating, by a thin MCSB phase that is formed by a deposition reaction of a Zn phase, thus forming a coating layer with improved processability and corrosion resistance.
[00359] In an example to achieve the above, it is preferable to set the temperature of the coating bath to a temperature above the melting point of the coating bath + 50 Ό or higher, and to cool to just below 400 Ό by quenching above 25 Ό / s. Specifically, it is preferable to adjust the temperature of the bath
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72/144 coating to the melting point of the coating bath + 50 Ό or more and quenching in a temperature range between the temperature of the coating bath and 375 Ό at an average cooling rate greater than 25 Ό / s after the coating treatment (after lifting the steel product from the coating bath). In a case where the temperature of the coating bath which is set to the melting point of the coating bath + 50Ό or more reaches a level below 500Ό, it is preferable to increase the temperature of the coating bath to 500 Ό or more.
[00360] Therefore, the Al phase is solidified as a primary crystal, and then the MgZn2 phase is solidified. The Zn phase is in a semi-molten state. When the Al phase is deposited, it releases elements when the solid solubility limit decreases sharply. In this state, as the Zn phase is in the liquid state, the alloying element migrates to the Zn phase in the molten state. Upon realizing this state, it is possible to obtain a Zn phase containing saturated elements, such as Mg, Sn and Ca. However, in a case where cooling is performed by quenching below 325 Ό, the equilibrium separation of a phase of thin MCSB cannot be achieved, and thus, a Zn phase is formed as an over-saturated solid solution. Therefore, a slow cooling solidification temperature range in which a thin MCSB phase is deposited must be provided during the process. In other words, when there is a certain time, a molten state Zn containing alloy elements, in particular, a large amount of Sn is formed.
[00361] In addition, when cooling is carried out in a temperature range between the coating bath temperature and 375 Ό at a rate of 25 Ό / s or less, although a thin phase of MCSB is present, the Thin MCSB cannot be incorporated into a Zn phase, which can prevent the formation of a
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73/144 desired coating layer. In addition, a ternary eutectic structure is likely to be formed and therefore the ability to protect against corrosion and protection against sacrificial corrosion, in particular, the ability to protect against sacrificial corrosion in the long term tend to deteriorate.
[00362] The temperature range over which a thin MCSB phase is finely and explosively deposited as a result of the equilibrium separation of a Zn phase is a temperature range between 375 Ό and 325 Ό, which is a temperature range of 350 Ό ± 25 Ό. In this temperature range, only the Zn phase is in the semi-molten state in the structure of a coating layer, and elements such as Mg, Ca and Sn migrate to the Zn phase of the Al phase and the MgZn2 phase with a decrease in the limit solid solubility due to complete solidification. In addition, as the Zn phase is sufficiently softened, elements such as Mg, Ca and Sn contained therein can be widely dispersed at the grain limit of the Zn phase together with a decrease in the temperature of the Zn phase. The temperature is also high enough to allow these elements to be dispersed.
[00363] Therefore, cooling is performed in a temperature range between 375 Ό and 325 Ό at a rate of less than 12.5 O / s (more preferably 10 Ό / s or less, even more preferably 7.5 Ό / s or less). This temperature history allows for the fine dispersion of a thin MCSB phase in a Zn phase. In a case where the Sn concentration is high, the finely dispersed MCSB phase can partially aggregate and become coarse. When cooling is performed at a cooling rate of 12.5 O / s or more, a thin MCSB phase cannot be separated and solidified, and a supersaturated solid solution is formed, which can result in extremely poor processability.
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74/144 [00364] In a case where the Ca concentration is high, a CZA phase is formed. However, a CZA phase is deposited before an Al phase and an MgZn2 phase when the temperature control described above is carried out, and the CZA phase is formed mainly near the interface. This is believed to be due to the fact that there are some initial deposition factors, such as high crystal conformation with a base metal.
[00365] In a case where Ca and Si are contained, a phase of Ca-AI-Si intermetallic compound and a phase of Mg-AI-Si intermetallic compound are formed in a coating layer. These phases of the intermetallic compound are formed immediately after the coating solidifies. The size depends on the temperature history up to about 350 Ό. When the cooling rate during solidification of the coating is high, an intermetallic compound phase tends to be slightly concentrated near the interface of a coating layer, and an intermetallic compound phase that has a small grain size of 1 pm or less it is formed in large quantities. However, when the cooling rate is small after the coating has solidified, an intermetallic compound phase that has a grain size greater than 1 pm is also observed, the number of an intermetallic compound phase decreases and the intermetallic compound phase is reduced. dispersed throughout the coating layer. Normally, it is more preferable for the processability of the coating layer that the phases of the intermetallic compound are widely dispersed through the ZnAI-Mg alloy layer. Therefore, the cooling rate at 350 Ό can be adjusted to less than 100 Ό / s. In other words, unless the water cooling process and the fog cooling process are carried out immediately after the coating layer solidifies, these intermetallic compound phases are basically
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75/144 present and widely dispersed in the Zn-AI-Mg alloy layer. [00366] In order to allow a coating layer to have an excellent plastic deformability, it is desirable that the Al phase described above is formed by attenuation to just below 400 Ό which grew in the form of dendrite (as long as there is no concern) with an Al phase formed by dendrite by slow cooling) disappears, thus forming a thin Zn-AI eutectoid structure. In order to achieve a thin Zn-AI eutectoid structure, it is preferable to keep the temperature in a range between 325 Ό and 250 Ό for more than 20 seconds, preferably more than 60 seconds.
[00367] In other words, the average cooling rate in a temperature range between 325 Ό and 250 Ό is, preferably, 3.75 Q / s or less. As the retention time in a temperature range between 325 Ό and 250 Ό is extended, the amount of phase of a thin Zn-AI eutectoid structure increases. In this temperature range, the Zn elements dissolved in the Al phase are released and the eutectoid transformation is induced. Once the Zn is released from the Al phase, a portion of the Al phase in the form of a dendrite is deformed to become a thin Zn-AI eutectoid structure. When this temperature range is maintained within 20 seconds or less, the content of the thin Zn-AI eutectoid structure tends to decrease.
[00368] The Al-Fe alloy layer to be formed in the base metal (steel product) is rapidly formed and grown in a period of less than 1 second immediately after immersion of the coating. The growth rate increases as the temperature increases and the growth rate increases even more as the time required for immersion in the coating bath is extended. When the Sn concentration reaches 1% or more, the growth rate increases even more. So when the concentration
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76/144 of Sn is high, it is necessary to select the appropriate immersion time according to the thickness of a desired Al-Fe alloy layer. Once the temperature of the coating bath reaches a temperature below 500 Ό, the growth is substantially terminated. Therefore, it is preferable to reduce the immersion time or immediately switch to the cooling process after solidification. [00369] Furthermore, a coated steel product is solidified once and reheated to redo its coating layer so that all constituent phases disappear and the coated steel product is in the form of a liquid phase. Therefore, for example, even a coated steel product that has been treated once by quenching or the like can be subjected to a structural control as specified here in the appropriate heat treatment step by reheating in an offline mode. In this case, it is preferable to set the temperature to reheat the coating layer immediately above the melting point of a coating bath, which is in a temperature range where the AlFe alloy layer does not overgrow.
[00370] Next, several measurement methods relating to the characteristics of a coating layer will be described.
[00371] The chemical component of a coating layer is measured by the following method.
[00372] An acidic solution is obtained by exfoliating and dissolving a coating layer with an acid containing an inhibitor that suppresses the corrosion of a base metal (steel product). Then, by measuring the acidic solution obtained by the ICP analysis, it is possible to obtain the chemical composition of the coating layer (in a case where the coating layer has a single layer structure of a Zn-AI-Mg alloy layer, a in which case the coating layer has the chemical composition of a Zn alloy layer
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Al-Mg and the coating layer has a stratified structure of an Al-Fe alloy layer and a Zn-AI-Mg alloy layer, in which case the coating layer has the chemical composition of an aluminum alloy layer. Al-Fe and a layer of Zn-AI-Mg alloy combined together). The acidic species is not particularly limited as long as an acid can dissolve the coating layer. The chemical composition is measured as an average chemical composition.
[00373] When it is desirable to obtain the respective chemical compositions of the Al-Fe alloy layer and the Zn-AIMg alloy layer, a calibration curve is obtained for the quantitative analysis of each element by GDS (high discharge spectrometry) frequency). After that, the chemical component towards the depth of the target coating layer can be measured. For example, several 30 mm square pieces are taken from a sample of the prepared coated steel sheet and used as GDS samples. Ion spraying in argon is carried out from the surface layer of the coating layer, in order to obtain a graph of the intensity of the element in the direction of depth. In addition, a standard sample of a pure metal sheet from each element is prepared and a graph of the intensity of the element is obtained in advance. Thus, it is possible to convert the concentration of the intensity graph. In a case where the GDS is used to analyze the chemical composition, it is preferable to define the analysis area as <p4 mm or more, perform the measurement 10 times or more and adopt the average value of the component in each location.
[00374] The crackle rate is preferably in the range of about 0.04 to 0.1 pm / s. In a case where the analysis value of the component of the Zn-AI-Mg alloy layer portion is adopted at each GDS analysis point, in order to eliminate the influence of the layer
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78/144 oxidized as an upper surface layer, it is preferable to ignore the component graph at a depth of 1 pm from the surface layer and adopt the average component value of each concentration element at a depth of 1 to 10 pm (width of 5 pm ).
[00375] In a case in which the chemical composition of an Al-Fe alloy layer is determined, a position where the intensity of the Fe element is 95% or more of the analysis of the entire element is designated as the position of the interface between a base metal (steel product) and a coating layer (Al-Fe alloy layer), and the surface side of the coating layer from the interface position is designated as an Al-Fe alloy layer. In addition to the above, the average component value at each element concentration with a width corresponding to the width of the thickness of the Al-Fe alloy layer is adopted based on the correspondence with the thickness of the Al-Fe alloy layer obtained by observation SEM or similar.
[00376] It is also possible to easily obtain individual chemical compositions of the Al-Fe alloy layer and the Zn-AIMg alloy layer from quantitative analysis values using ΕΡΜΑ.
[00377] A method of identifying each phase of a layer of a Zn-AI-Mg alloy (each phase excluding a ternary eutectic structure of Zn-AI-MgZn2) is as follows.
[00378] In order to observe the structure of a Zn-AI-Mg alloy layer, it is possible to measure the thickness of an AlFe alloy layer and a Zn-AI-Mg alloy layer by polishing a cross section of Zn-AI-Mg alloy layer and observing the structure after nital chemical etching. It is possible to observe the structure of the Zn-AI-Mg alloy layer with greater precision by processing CP. It is preferable to use FE-SEM for observation of the ZnAI-Mg alloy layer.
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79/144 [00379] The fraction of the area of each phase in an alloy layer of
Zn-AI-Mg (each phase excluding a ternary eutectic structure of ZnAI-MgZn2) is measured by the following method.
[00380] To measure the area fraction of each phase in an alloy layer of Zn-AI-Mg, FE-SEM and TEM equipped with EDS (energy dispersion X-ray spectrometry device) are used. A ΕΡΜΑ system can be used to identify each phase.
[00381] An optional section (a section cut in the direction of thickness) of a Zn-AI-Mg alloy layer to be measured is processed using CP (CROSS SECTION POLISHER). After CP processing, an SEM reflection electron image of the Zn-AI-Mg layer section is obtained. The SEM reflection electron image is determined to be an image (about the thickness of a Zn-AI-Mg alloy layer in pm x over 150 pm) obtained by looking at three or more areas for area measurement with a magnification of 1000 tunes in an optional square region that is approximately 100 pm or more in size (thickness direction: selected field of view into which the Zn-AI-Mg alloy layer fits) χ 2000 pm (in the direction parallel to the surface of a steel product).
[00382] Next, an optional section (a section cut in the direction of the thickness of the Zn-AI-Mg alloy layer) of the same Zn-AI-Mg alloy layer to be measured is processed by FIB (ion beam focused). After FIB processing, an electron diffraction image of a sectional structure of the Zn-AI-Mg alloy layer is obtained by TEM (transmission electron microscope). Subsequently, metals or intermetallic compounds contained in the Zn-AI-Mg alloy layer are identified.
[00383] Next, the SEM reflection electron image is compared with the results of identification of the TEM electron diffraction image, and each phase of the Zn-AI-Mg alloy layer is identifiedPetition 870190071281, 07/25 / 2019, p. 87/194
80/144 da based on SEM electron reflection image. In the identification of each phase of the Zn-AI-Mg alloy layer, it is recommended that the spot analysis of EDS is performed to compare the results of the spot analysis of EDS with the results of identification of the TEM electron diffraction image.
[00384] Next, in the SEM reflection electron image, the three values of lightness, hue and gray scale contrast indicated by each phase in the Zn-AI-Mg alloy layer are determined. The three values of brightness, hue and contrast indicated by each phase reflect the atomic number of the element contained in each phase. Therefore, in general, a phase with large contents of Al and Mg with small atomic numbers tends to have a black color, and a phase with a large content of Zn tends to have a white color.
[00385] Based on the EDS correspondence results described above, the computer image processing that changes the color only in the range of the three values described above, indicated by each phase contained in the Zn-AI-Mg alloy layer, is performed in order to obtain consistency with the SEM electronic reflection image (for example, the area (number of pixels) of each phase in the visual field is calculated showing only a specific phase as a white image). When performing this image processing for each phase, the area fraction of each phase in the ZnAI-Mg alloy layer is determined in the SEM electronic reflection image.
[00386] The area fraction of each phase of the Zn-AIMg alloy layer is determined to be the average value of the area fraction of each phase obtained by the operation described above in at least three fields of view of an optional cross section of the Zn-AI-Mg alloy layer (a section obtained by cutting in the direction of the thickness of the Zn-AI-Mg alloy layer).
[00387] The area fraction of a Zn phase including a Zn phase
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Thin MCSB is determined to be the area fraction of a Zn phase including a thin MCSB phase, which is a Zn phase in which the thin MCSB phase has been confirmed in the closed Zn phase region.
[00388] In addition, the area fractions of a Zn phase, an MgZn2 phase and an Al phase are area fractions different from the area fractions of an Al phase and a Zn phase present in the Zn- eutectoid structure. Thin AI and an MgZn2 phase, an Al phase and a Zn phase present in the ternary eutectic structure Zn-AI-MgZn2. [00389] Here, as shown in Figures 2 and 4, each SEM image of the cross section of a Zn-AI-Mg alloy layer was taken as a reflection electron image. Normally, the phases that make up a Zn-AI-Mg alloy layer (such as an Al phase, an MgZn2 phase and a Zn phase) can be readily distinguished due to the fact that their atomic numbers are obviously different.
[00390] A thin MCSB phase and a massive MCSB phase contained in a Zn phase can also be easily distinguished due to the fact that, compared to the Zn, Mg and Sn phase, with small atomic numbers, they are linked each other and therefore can be confirmed with darker contrast than the Zn phase.
[00391] Other intermetallic compound phases (such as a Ca-AI-Si intermetallic compound phase, an Mg-AI-Si intermetallic compound phase, and a CAZ phase) may show contrast similar to that of an MgZn2 phase. However, these phases can be distinguished relatively easily because of their unique forms.
[00392] For the area fraction of each phase, a phase that falls within the grain size range of interest is selected, and the area fraction of it is determined.
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82/144 [00393] In a case where it is difficult to distinguish each phase, electron beam diffraction by TEM or EDS point analysis is performed.
[00394] Each of the Al phase, the MgZn2 phase, the Zn phase and the CZA phase is often observed with a grain size of 1 pm or more and is easily identified using EDS. A Ca-AI-Si intermetallic compound phase and an Mg-AI-Si intermetallic compound phase also vary in shape. However, generally, each of them is often seen at a size of 1 pm or more, and is easily identified using EDS.
[00395] Here, for the area ratio of a thin MCSB phase that has a grain size of less than 1 pm in a Zn phase (in other words, the area fraction of a thin MCSB phase that has a size less than 1 pm in relation to a Zn Phase containing a thin MCSB phase), the magnification of the field of view used here is 10,000 times due to the fact that the thin MCSB phase is finely deposited in a distributed manner in the Zn phase. When observing a Zn phase in a field of view with a magnification of about 10,000 times, it is possible to easily confirm a thin MCSB phase contained in the Zn phase and also its grain size.
[00396] The area fraction of a thin MCSB phase is determined in a field of view of 3 pm x 3 pm (magnification 10000 times) including the Zn phase. The same operation is performed on 20 or more fields of view. The average value of the fractions of the obtained area is determined as the fraction of the area of the thin MCSB phase in the Zn phase.
[00397] The average grain size of the fine MCSB phase in the Zn phase is measured by the following method.
[00398] Upon SEM observation to measure the area fraction of the thin MCSB phase described above, among the recognized thin MCSB phases, thin MCSB phases having the 5 sizes are selected
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83/144 grains less than 1 pm. This operation is performed for 5 fields of view. The arithmetic mean of 25 grain sizes in total is determined to be the average grain size of a
Thin MCSB having a grain size of less than 1 pm.
[00399] In other words, the average grain size of a thin MCSB phase means the average grain size for a phase that has a grain size of less than 1 pm even in a case where a massive MCSB phase (phase of massive MgSn intermetallic compound) which has a grain size of 1 pm or more is included in it.
[00400] The average grain size of a Ca-AI-Si intermetallic compound phase and an MgAl-Si intermetallic compound phase is measured by the following method.
[00401] By SEM observation to measure the area fraction of each phase described above, among the confirmed compound phases, compound phases having the top 5 grain sizes are selected. This operation is performed for 5 fields of view. The arithmetic mean of 25 grain sizes in total is determined to be the average grain size of a Ca-Zn-AI intermetallic compound phase or that of a Ca-Zn-AI-Si intermetallic compound phase.
[00402] The thin Zn-AI eutectoid structure (eutectoid structure having a lamellar spacing of less than 300 nm composed of a Zn phase and an Al phase) is identified and its area fraction is determined by the following method.
[00403] A structure in which two phases, an Al phase and a Zn phase are codeposited is identified based on an SEM reflection electron image by the same method as the area fraction of each phase in the Zn-AI layer -Mg (see Figures 6 and 7). A part of the structure is seen in a rectangular field of view that is 3 pm x 4 pm in size (5 pm diagonal line) with
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84/144 a magnification of 30000 times (see Figure 13). At this point, when two diagonal lines are drawn in a rectangular field of view, the observed structure is determined to be a thin eutectoid Zn-AI structure in a case where each diagonal line crosses a Zn phase and an Al phase 10 times or more, and the average value of the distance from center to center between two adjacent phases of Zn through an phase of Al, which is a diagonal length, is less than 300 nm.
[00404] Then, the operation described above is performed repeatedly on the SEM reflection electron image (image having a thickness of the Zn-AI-Mg χ alloy layer about 150 pm observed with a magnification of 1000 times) the same used to measure the area fraction of each phase in the Zn-AI-Mg alloy layer in order to confirm the continuity of the thin Zn-AI eutectoid structure and to understand the outline of the Zn-AI eutectoid structure (region) slim. Then, the area fraction of the thin Zn-AI eutectoid structure in the Zn-AI-Mg alloy layer in the obtained SEM reflection electron image is determined.
[00405] The area fraction of the thin Zn-AI eutectoid structure is determined to be the average area fraction of the thin Zn-AI eutectoid structure obtained by the operation described above in at least three fields of view of an optional cross section of the Zn-AI-Mg alloy layer (section obtained by cutting in the direction of the thickness of the Zn-AI-Mg alloy layer).
[00406] The ternary eutectic structure of Zn-AI-MgZn ₂ in the Zn-AI-Mg alloy layer is identified and the area fraction thereof is measured by the following methods.
[00407] A structure in which three phases, an Al phase, a Zn phase and an MgZn ₂ phase, are codeposited, is identified based on an SEM electronic reflection image by the same method
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85/144 than the area fraction of each phase in the Zn-AI-Mg alloy layer. A part of the structure is seen in a rectangular field of view that is 3 pm x 4 pm in size (5 pm diagonal line) with a magnification of 30000 times (see Figure 14). At this point, when two diagonal lines are drawn in a rectangular field of view, the structure is determined to be a ternary eutectic structure in a case where each diagonal line crosses the Zn phase 5 times or more and the MgZn2 phase or phase of Al that extends around the Zn phase 5 times or more. This determination is based on the fact that the structure is a structure in which three phases are each finely dispersed, in particular for a ternary eutectic structure.
[00408] Note that the structure is determined to be a ternary eutectic structure in a case in which the ternary eutectic structure is located, a case in which the ternary eutectic structure cannot have a region of 3 pm x 4 pm due to a composition that it is unlikely to form a ternary eutectic structure, or a case in which the structure is divided into 1 pm square grids, and each grid contains at least one from each phase.
[00409] Then, the operation described above is performed repeatedly on the SEM reflection electron image (image having a thickness of the Zn-AI-Mg χ alloy layer about 150 pm observed with a magnification of 1000 times) the same used to measure the area fraction of each phase in the Zn-AI-Mg alloy layer to confirm the continuity of the ternary eutectic structure and understand the outline of the ternary eutectic structure (region). The area fraction of the ternary eutectic structure in the Zn-AI-Mg alloy layer in the SEM electronic reflection image is determined.
[00410] The area fraction of the ternary eutectic structure is determined to be the average area fraction of the ternary eutectic structure
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86/144 obtained by the operation described above in at least three fields of view of an optional cross section of the Zn-AIMg alloy layer (section obtained by cutting in the direction of the thickness of the Zn-AI-Mg alloy layer).
[00411] Next, the conditions for measuring X-ray diffraction (XRD) will be described.
[00412] Regarding the X-ray diffraction intensity, Cu, Co and the like can be used for the radiation source. However, eventually it is necessary to calculate and change the diffraction angle according to the source of Cu radiation. The x-ray output at 40 kV and 150 mA is adjusted. The measuring range is preferably from 5 to 90 °, and the step is preferably from about 0.01 °. To reach the intensity (cps) at a given diffraction angle, an average value of about ± 0.05 ° is obtained. In other words, for an intensity of 23.3 °, an average value of 22.25 ° to 22.35 ° is obtained. It is necessary to obtain each intensity index by not taking measures such as bottom removal to clarify the peak before calculating the average intensity value.
[00413] Next, the further treatment that can be applied to the coated steel plate of the development will be described.
[00414] A film can be formed in the coating layer of the coated steel plate of the development. A film having one or more layers can be formed. Examples of a film formed immediately above the coating layer include, for example, a chromate film, a phosphate film and a chromate-free film. Chromate treatment, phosphate treatment and chromate free treatment to form these films can be carried out by known methods.
[00415] Examples of treatment with chromate include treatment with electrolyte chromate to form a chromate film for itPetition 870190071281, 07/25/2019, p. 94/194
87/144 trolysis, reactive chromate treatment to form a film using a reaction with a material and then washing off an excess treatment solution and coating type chromate treatment to apply a treatment solution to a coated object and dry the solution to form a film without washing with water. Either treatment can be adopted.
[00416] An example of electrolyte chromate treatment is the treatment of electrolyte chromate using chromic acid, silica sol, a resin (such as phosphoric acid, acrylic resin, vinyl ester resin, vinyl acetate acrylic emulsion, styrene butadiene latex carboxylated or diisopropanolamine modified epoxy resin) and hard silica.
[00417] Examples of phosphate treatment include, for example, treatment with zinc phosphate, treatment with calcium and zinc phosphate and treatment with manganese phosphate.
[00418] Chromate-free treatment is particularly suitable due to the fact that it is free of environmental burden. Examples of chromate-free treatment include chromate-free electrolytic treatment to form a chromate-free film by electrolysis, reactive chromate-free treatment to form a film using a reaction with a material and then wash off an excess treatment solution, and free treatment of chromate coating type to apply a treatment solution to a coated object and dry the solution to form a film without washing with water. Either treatment can be adopted.
[00419] In addition, one or more layers of an organic resin film can be provided in the film immediately above the coating layer. Organic resin is not limited to a specific type, and examples include, for example, polyester resin, polyurethane resin, epoxy resin, acrylic resin, polio resin
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88/144 lefin and denatured products from these resins. Here, the term denatured product refers to a resin obtained by reacting a reactive functional group contained in the structure of any of these resins with a different compound (such as a monomer or a crosslinking agent) containing a functional group capable of reacting with the functional group.
[00420] As such organic resin, one or more types of organic resins (not denatured) can be mixed for use, or one or more types of organic resins obtained by denaturing at least one different organic resin in the presence of at least one resin organic can be mixed and used in combination. In addition, an organic resin film can optionally contain a coloring pigment and / or an anti-rust pigment. It is also possible to use a water-based organic resin obtained by dissolving or dispersing the resin in water.
EXAMPLES [00421] Examples of the disclosure will be described. However, the conditions in the examples are adopted in conditional examples to confirm the feasibility and effects of the disclosure, and the disclosure is not limited to the conditional examples. The revelation can adopt several conditions, as long as the purpose of the revelation is achieved without departing from the scope of the revelation.
EXAMPLE A [00422] In order to obtain coating layers for the chemical compositions shown in Tables 1-1 to 1-8, a given amount of pure metal ingot was used and melted in a vacuum melting furnace, followed by the initial composition of the coating bath in the air. For the preparation of coated steel sheets, a batch type melting coating system was used.
[00423] No. 119 is a steel plate coated with bas and Zn-AI-Mg
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89/144 commercially available prepared as a comparative material. 2.3 mm hot-rolled carbon steel (C <0.1% concentration) was used for a coating base plate, and degreasing and pickling were carried out immediately before the coating step.
[00424] In any sample preparation, the same reduction treatment method was applied to the base coat plate until immersion in the coating bath. In other words, the base coat plate was heated from room temperature to 800 Ό by electric heating in an environment of N2-H2 (5%) (dew point of -40 Ό or less, the lower oxygen concentration at 25 ppm), maintained for 60 seconds, cooled to the coating bath temperature of + 10 ° C by spraying N2 gas, and immediately immersed in the coating bath. The immersion time of the coating bath for each coating steel plate was set to 1 second. The N2 gas cleaning pressure was adjusted to prepare a coated steel sheet so that the coating thickness was set to 30 mm (± 1 mm).
[00425] The coating step was carried out in the five different ways described below.
[00426] Production method A: The temperature of the coating bath has been adjusted to 0 melting point of the coating bath + 20 Ό. The immersion time of the coating bath was set to 1 second. A coating layer was obtained in the cooling process in which after raising the coating base sheet of the coating bath, the average cooling rate of the coating bath temperature to 375 Ό was adjusted to 20 (± 5) O / s , the average cooling rate from 375 Ό to 325 Ό was adjusted to 15 (± 2.5) Ό / s, the average cooling rate from 325 ⁰ C to 250 Ό was adjusted
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90/144 to 12.5 (± 2.5) O / s, and the average rate of restraint from 250 Ό to 100 Ό was adjusted to between 5 Ό and 12 O / s.
[00427] Production method B: The coating bath temperature has been adjusted to the melting point of the coating bath + 50 Ό (note that, in a case where the temperature was below 500 Ό, it was adjusted to 500 Ό ). The immersion time of the coating bath was adjusted to 1 second. A coating layer was obtained in the cooling process in which, after raising the coating base sheet of the coating bath, the average cooling rate of the coating bath temperature to 375 Ό was adjusted to 20 (± 5) O / s , the average cooling rate from 375 Ό to 325 Ό was adjusted to 10 (± 2.5) O / s, the average cooling rate from 325 Ό to 250 Ό was adjusted to 5 (± 1.25) Ό / s, and the average cooling rate from 250 Ό to 100 Ό has been adjusted to between 5 Ό and 12 O / s.
[00428] Production method C: The temperature of the coating bath has been adjusted to the melting point of the coating bath + 50 Ό (note that in a case where the temperature was below 500 Ό, it was adjusted to 500 Ό ). The immersion time of the coating bath was adjusted to 1 second. A coating layer was obtained in the cooling process in which, after lifting the base coat plate from the coating bath, cooling was carried out at an average cooling rate of 30 (± 5) O / s of the bath temperature of coating to 375 Ό, and then cooling by mist cooling was performed immediately at an average cooling rate of 12.5 Ό to 1000 Ό / s or more than 375 <C to 25 <C.
[00429] Production method D: The temperature of the coating bath has been adjusted to the melting point of the coating bath + 50 Ό (note that in a case where the temperature was below 500 Ό, it was adjusted to 500 Ό ). The immersion time of the reverse bath
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91/144 timeout was set to 1 second. A coating layer was obtained in the cooling process in which, after raising the coating base sheet of the coating bath, the average cooling rate of the coating bath temperature to 375 Ό was adjusted to 30 (± 5) Ό / s , the average cooling rate from 375 Ό to 325 Ό was adjusted to 10 (± 2.5) Ό / s, the average cooling rate from 325 Ό to 250 Ό was adjusted to 5 (± 1.25) Ό / s, and the average cooling rate from 250 Ό to 100 Ό has been adjusted to between 5 Ό and 12 O / s. [00430] Production method Ε: The temperature of the coating bath has been adjusted to the melting point of the coating bath + 50 Ό (note that in a case where the temperature was below 500 Ό, it was adjusted to 500 Ό ). The immersion time of the coating bath was adjusted to 1 second. A coating layer was obtained in the cooling process in which, after raising the coating base sheet of the coating bath, the average cooling rate of the coating bath temperature to 375 Ό was adjusted to 30 (± 5) Ό / s , the average cooling rate from 375 Ό to 325 Ό was adjusted to 10 (± 2.5) Ό / s, the average cooling rate from 325 Ό to 250 Ό was adjusted to 2.5 (± 1.25) ) ° C / s and the average cooling rate from 250 Ό to 100 Ό has been adjusted to between 5 Ό and 12 O / s.
X-RAY DIFFERENCE ANALYSIS [00431] A 20 x 20 mm square was cut from each resulting coated steel sheet and an X-ray diffraction image was obtained from the surface of the coating layer. Measurement conditions included the use of an X-ray diffractometer (RINT 1500) and a RINT 1000 wide-angle goniometer manufactured by Rigaku Corporation with a 40 kV and 150 mA X-ray output, scanning speed of 2 7min and one step 0.01 ° in a scan range from 5 ° to 90 °. The incident slot has been set to 1 °, and the receiving slot
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92/144 of light was adjusted to 1 ° 0.15 mm. Specific intensity I (phase of
Thin MCSB), specific intensity I (MgCaSn + MggSns) and specific intensity I (CaZnAI) (written as I (MCSB), I (MgCaSn) and I (CaZnAI), respectively, in Tables) were calculated.
[00432] Furthermore, for I (MgCaSn) in Table 1, when the quantity of the MCSB phase was small and the numerical value could not be calculated, it was written as I (23.3 ° of intensity (cps)) as well is shown in column I (23, S ') in Table 1.
[00433] A 20 x 20 mm square was cut from the resulting coated steel sheet, and the position of a strongest diffraction peak around 23.00 ° and 23.46 ° was determined based on the image of X-ray diffraction from the surface of the coating layer. In one case where a diffraction peak of the strongest intensity appeared in a range between 23.36 ° and 23.46 ° it was written as ΌΚ, and in a case where such a diffraction peak was not obtained, it was written as NG .
MEASUREMENT OF EACH FRACTION OF EACH PHASE [00434] A sample piece that has a cross section of the coating layer (section cut along the direction of the thickness of the coating layer) was cut from each coated steel sheet obtained. The fractions of the area of the following phases present in the Zn-AI-Mg alloy layer were measured according to the method described above.
Area fraction of a Zn phase including a thin MCSB phase (written as Zn + MCSB in Tables)
Area fraction of a thin MCSB phase contained in a Zn phase (written as MCSB / Zn in Tables)
Area fraction of a thin Zn-AI eutectoid structure (written as a thin ZnAI structure in Tables)
Area fraction of an Al phase
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Area fraction of an MgZri2 phase
Area fraction of a ternary eutectic structure of ZnAI-MgZn2 (written as ternary eutectic structure in the tables) MEASUREMENT OF AVERAGE GRAIN OF THE FINE MCSB PHASE CONTAINED IN THE ZN PHASE [00435] A sample piece that has a cross section of the coating (section cut along the direction of the thickness of the coating layer) was cut from each coated steel sheet obtained. The average grain size of the thin MCSB phase contained in the Zn phase was determined according to the method described above. The average grain size of the thin MCSB phase is shown in the Dc column of MCSC / Zn for the area fraction.
FLAT SURFACE CORROSION RESISTANCE [00436] To compare the corrosion resistance of the flat surface, each production sample was subjected to 60 cycles of an accelerated corrosion test (JASO M609-91) to remove white rust, and the corrosion resistance was evaluated based on the thickness reduction due to corrosion. The approval criteria were determined based on the commercially available Zn-AI-Mg coated steel plate (comparative material No. 119), and a thickness reduction of less than 10 pm, which was less than the amount of corrosion of the steel sheet coated with Zn-AI-Mg, was rated as A, and a thickness reduction of 10 pm or more was rated as B.
CORROSION RESISTANCE OF THE FINAL SURFACE [00437] To compare the corrosion resistance of the cut end surface, a 2.3 mm thick (25 pm) material was cut into a 30 mm square and placed in a constant temperature chamber and humidity (placed horizontally (O ')). One cycle was as follows: (50 Ό, 99%, 24 hours) -> transition over 6
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94/144 hours -> (50 Ό, 35%, 66 hours). An appearance test was conducted after a cycle, the fraction of the average red rust area of the cut end surface of the coated steel sheet was obtained from the four-sided cutting cross section of the coated steel sheet. The approval criteria were determined based on the commercially available Zn-AI-Mg coated steel plate (comparative material No. 119), and the fraction of the red rust area at the bottom of the cut end surface was measured.
[00438] In other words, a fraction of red rust area of 70% or more, which was greater than the fraction of red rust area of the steel sheet coated with Zn-AI-Mg, was evaluated as B, an area fraction of 35% to 70% was assessed as A, a fraction of red rust area of 10% to 35% was assessed as AA, and a fraction of red rust area of less than 10% was assessed as AAA .
[00439] The fraction of the red rust area at the bottom of the cut end surface after 5 cycles of the same type of cycle has also been measured. A fraction of red rust area of 90% or more, which was greater than the red rust fraction of the commercially available Zn-AI-Mg coated steel plate, was assessed as B, a red rust fraction of 45 % to 90% was rated as A, and a fraction of red rust area of less than 45% was rated as AAA.
CORROSION POTENTIAL [00440] The corrosion potential of the coated steel sheet was measured in a 5% aqueous NaCI solution using Ag / AgCI as a reference electrode and an electrochemical measuring cell. The average value of the corrosion potential was measured for 30 seconds immediately after immersion.
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SALT SPRAYING TEST (WRITTEN AS SST IN THE
TABLES) [00441] To assess the resistance to white rust on the flat surface of the coated steel sheet, the coated steel sheet was subjected to a salt spray test (JIS Z 2371) to measure the fraction of the white rust area of the coated surface after 120 hours. The approval criteria were determined based on the commercially available steel sheet coated with Zn-AI-Mg (comparative material No. 119) and a fraction of white rust area of 50% or more, which was greater than a fraction of white rust area of 50% for steel sheet coated with Zn-AI-Mg, was rated as B, a fraction of white rust area of 20% to 50% was rated as A and a fraction of rust area less than 20% was assessed as AAA.
[00442] To assess the processability of the coating layer, the coated steel sheet was subjected to a 5R-90 ° V flexion test and cellophane tape having a width of 24 mm was pressed against and removed from a bend in V shape so as to visually judge the dust.
[00443] A case in which the powder exfoliated due to spraying adhered to the tape was rated as B.
[00444] A case in which the powder exfoliated due to the spray adhered in points to the tape was evaluated as A.
[00445] One case in which powder exfoliation did not occur was rated AAA.
POWDER REDUCTION [00446] In order to evaluate the additional intensified processing, after molding with a 2R-90 ° V-shaped press, the inflection processing was also carried out on a flat plate with a flat matrix. After processing in a V-shape, the CePetition tape 870190071281, from 07/25/2019, p. 103/194
96/144 lofane which has a width of 24 mm was pressed against and away from a valley fold, in order to visually assess the dust.
[00447] A case in which no part of the exfoliation was generated was assessed as AAA.
[00448] A case where parts of exfoliation were partially observed as spots was rated as A.
[00449] A case in which the parts of the exfoliation were observed as lines was evaluated as B.
STRETCH MICROSPHERE TEST [00450] A stretch ball test was performed to assess the processability of the coating layer. The pressing load was adjusted to 3, 6 and 9 kN, and NOX-RUST 550 NH was used as oil at an extraction speed of 100 mm / min, and the SKD mold (R = 4) was used. In a case in which the dynamic friction coefficient of the steel sheet coated on the basis of existing Zn-AI-Mg was less than 0.12 without wear, it was assessed as A and in a case in which the dynamic friction coefficient was 0.12 or galling was observed, it was rated as B.
COATING LAYER HARDNESS (VICKERS HARDNESS) [00451] The hardness of the coating layer of each coated steel sheet was measured using a Vickers hardness tester (MlTUTOYO-HM221) to measure the hardness on the side of the coated surface. The test load was adjusted to 10 gf and the average value of 50 points was measured.
[00452] Tables 1-1 to 1-12 show the lists in example A.
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TABLE 1-1
n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group CO (O Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B TO 1 Ç 380 500 Production method D 87.7 5 5 1 0.2 0 0.1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A2 AND 380 500 Production method D 84.8 5.5 3.5 5 0 0 0.5 0.1 0 0 0 0 0 0 0 0 0 0 0 0.2 0 0 0.4 0 A3 AND 380 500 Production method D 85.2 5.5 3.5 5 0 0 0.5 0.1 0 0 0 0 0 0 0 0 0 0 0 0.2 0 0 0 0.4 A4 AND 370 500 Production method D 87.5 5.5 4 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A5 Ç 380 500 Production method D 84.4 5.5 3.5 5 0 0 0.5 0.1 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0.5 0 A6 Ç 380 500 Production method D 84.9 5.5 3.5 5 0 0 0.5 0.1 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0.5 A7 AND 355 500 Production method D 69 6 4.5 20 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A8 AND 410 500 Production method D 84.4 9 4.5 1 0 0 0.1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A9 Ç 410 430 Production method A 84.4 9 4.5 1 0 0 0.1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A10 Ç 410 500 Production method B 84.4 9 4.5 1 0 0 0.1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A11 ç 410 500 Production method C 84.4 9 4.5 1 0 0 0.1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group CO (O Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A12 AND 410 500 Production method D 84.1 9 4.5 1 0 0 0.1 0 0 0 0 0 0 0 0 0 0 0 0 1 0.1 o, 1 o, 1 0 A13 Ç 410 500 Production method D 83.8 9 4.5 1 0 0 o, 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0.2 0.2 0.2 0 A14 AND 400 500 Production method D 79.7 10 6 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.3 0 0 0 0 A15 Ç 410 500 Production method D 84.6 10 4.5 0.2 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 0.4 0 0 0 0 A16 AND 410 500 Production method D 83.9 10 4.5 0.5 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 0.4 0 0.4 0 0 A17 Ç 410 500 Production method D 83.8 10 4.5 0.5 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 0.4 0 0.5 0 0 A18 AND 410 500 Production method D 83.8 10 4.5 1 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 0.4 0 0 0 0 A19 AND 405 500 Production method D 82.8 10 4.5 2 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 0.4 0 0 0 0 A20 AND 400 500 Production method D 78.47 11 5 5 0 0 0.03 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A21 Ç 410 500 Production method D 77.25 11 5 5 0 0 0.05 0.7 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A22 AND 420 500 Production method D 81.85 11 6 0.1 0 0 0.05 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A23 AND 420 500 Production method D 78.7 11 6 0.3 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group CO (O Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A24 AND 420 500 Production method E 78.5 11 6 0.5 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A25 Ç 420 440 Production method A 79.5 11 6 0.5 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A26 Ç 420 500 Production method B 79.5 11 6 0.5 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A27 ç 420 500 Production method C 79.5 11 6 0.5 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A28 AND 420 500 Production method E 75.5 11 7 4 0 0 1 0.5 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A29 AND 410 500 Production method E 80.4 11 5.5 2 0 0 0.3 0 0.2 0 0.2 0 0 0 0 0 0 0 0 0.4 0 0 0 0 A30 Ç 410 500 Production method E 78.8 11 5.5 2 0 0 1 0 0.5 0.2 0 0 0 0 0 0 0 0 0 1 0 0 0 0
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TABLE 1-2
n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A31 AND 410 500 Production method E 79.1 11 5.5 2 0 0 1 0 0.4 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A32 Ç 410 500 Production method D 79 11 5.5 2 0 0 1 0 0 0.5 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A33 AND 410 500 Production method D 79.1 11 5.5 2 0 0 1 0 0 0.4 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A34 AND 405 500 Production method D 77.8 11 5.5 5 0 0 0 0 0 0 0.2 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A35 AND 405 500 Production method D 77.6 11 5.5 5 0 0 0 0 0 0 0.2 0 0 0 0.2 0 0 0 0 0.5 0 0 0 0 A36 Ç 405 500 Production method D 77.55 11 5.5 5 0 0 0 0 0 0 0.2 0 0 0 0.25 0 0 0 0 0.5 0 0 0 0 A37 AND 405 500 Production method D 77.8 11 5.5 5 0 0 0 0 0 0 0.2 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A38 AND 405 500 Production method D 77.6 11 5.5 5 0 0 0 0 0 0 0.2 0 0 0 0 0.2 0 0 0 0.5 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A39 Ç 405 500 Production method D 77.55 11 5.5 5 0 0 0 0 0 0 0.2 0 0 0 0 0.25 0 0 0 0.5 0 0 0 0 A40 Ç 415 500 Production method D 82.5 11 5.5 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A41 AND 415 500 Production method D 81.2 11 5.5 0.5 0.1 0 0.5 0 0 0.1 0 0 0 0.1 0 0 0 0 0 1 0 0 0 0 A42 AND 410 500 Production method D 78.7 11 5.5 3 0.1 0 0.5 0 0 0.1 0 0 0 0.1 0 0 0 0 0 1 0 0 0 0 A43 AND 405 500 Production method D 76.7 11 5.5 5 0.1 0 0.5 0 0 0.1 0 0 0 0.1 0 0 0 0 0 1 0 0 0 0 A44 Ç 375 500 Production method D 56.2 12 8 22 0 0 0.8 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A45 Ç 420 500 Production method D 80.3 12 5 1 0.5 0.5 0 0 0 0 0.2 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A46 AND 420 500 Production method E 80.7 12 5 1 0.3 0.3 0 0 0 0 0.2 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A47 AND 420 500 Production method E 80.5 12 5 1 0.2 0.2 0.1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A48 AND 420 500 Production method E 80.7 12 5 1 0.1 0.1 0.1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A49 AND 420 500 Production method D 75.7 12 6 5 0 0 0.3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A50 AND 420 500 Production method E 75.4 12 6 5 0 0 0.3 0 0 0 0.1 0.1 0.1 0 0 0 0 0 0 1 0 0 0 0 A51 AND 420 500 Production method D 75.4 12 6 5 0 0 0.3 0 0 0 0.1 0.1 0 0.1 0 0 0 0 0 1 0 0 0 0 A52 AND 420 500 Production method E 75.4 12 6 5 0 0 0.3 0 0 0 0.1 0.1 0 0 0.1 0 0 0 0 1 0 0 0 0 A53 AND 420 500 Production method E 75.4 12 6 5 0 0 0.3 0 0 0 0.1 0.1 0 0 0 0 0 0.1 0 1 0 0 0 0 A54 Ç 420 500 Production method E 75.3 12 6 5 0 0 0.3 0 0 0 0.1 0.1 0 0.1 0.1 0 0 0 0 1 0 0 0 0 A55 AND 420 500 Production method E 66.4 12 8 10 0.5 0 1.5 0 0.1 0.1 0 0 0 0 0 0 0 0 0 1 0.4 0 0 0 A56 AND 415 500 Production method E 65.5 12 8 11 0.5 0 1.5 0 0.1 0 0 0 0 0 0 0 0 0 0 1 0.4 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A57 Ç 415 500 Production method E 65.4 12 8 11 0.5 0 1.5 0 0.1 0 0 0 0 0 0 0 0 0 0 1 0.5 0 0 0 A58 AND 420 500 Production method E 65.7 13 7 9 4 0 0.3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A59 AND 430 500 Production method D 76.5 13 6 3 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
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TABLE 1-3
n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A60 Ç 430 450 Production method A 76.5 13 6 3 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A61 Ç 430 500 Production method B 76.5 13 6 3 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A62 Ç 430 500 Production method C 76.5 13 6 3 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A63 AND 430 500 Production method D 76.3 13 6 3 0 0 0.5 0 0 0 0 0 0 0 0 0 0.2 0 0 1 0 0 0 0 A64 Ç 430 500 Production method D 76.25 13 6 3 0 0 0.5 0 0 0 0 0 0 0 0 0 0.25 0 0 1 0 0 0 0 A65 AND 430 500 Production method E 77 13 6 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A66 AND 430 500 Production method D 76.8 13 6 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0.2 0 1 0 0 0 0 A67 Ç 430 500 Production method D 76.75 13 6 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0.25 0 1 0 0 0 0 A68 Ç 450 500 Production method D 65.5 14 9 5 5 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A69 ç 440 500 Production method D 65.7 14 8 9 0 2 0.2 0.1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A70 AND 435 500 Production method D 71.7 14 7 5 0 1 0.3 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A71 AND 450 500 Production method D 65.5 15 11 5 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A72 Ç 445 500 Production method D 74.45 15 8.5 0.05 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A73 AND 440 500 Production method D 73.5 16 5 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A74 AND 460 510 Production method D 66.5 16 11 5 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A75 AND 460 510 Production method D 65.3 16 11 5 0 0 0.5 0 0 0 0 0.2 0 0 0 0 0 0 0 2 0 0 0 0 A76 Ç 460 510 Production method D 65.75 16 11 5 0 0 0.5 0 0 0 0 0.25 0 0 0 0 0 0 0 1.5 0 0 0 0 A77 AND 460 510 Production method D 65.5 16 11 6 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A78 AND 460 510 Production method D 65.3 16 11 6 0 0 0.5 0 0 0 0 0 0.2 0 0 0 0 0 0 1 0 0 0 0 A79 Ç 460 510 Production method D 65.25 16 11 6 0 0 0.5 0 0 0 0 0 0.25 0 0 0 0 0 0 1 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A80 AND 460 510 Production method D 65.5 16 12 5 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A81 AND 460 510 Production method D 65.3 16 12 5 0 0 0.5 0 0 0 0 0 0 0.2 0 0 0 0 0 1 0 0 0 0 A82 Ç 460 510 Production method D 65.45 16 12 5 0 0 0.3 0 0 0 0 0 0 0.25 0 0 0 0 0 1 0 0 0 0 A83 AND 450 500 Production method D 75 17 5 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A84 AND 455 505 Production method D 72.5 17 6 2.5 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A85 Ç 455 475 Production method A 71.5 17 6 2.5 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 A86 Ç 455 505 Production method B 71.5 17 6 2.5 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 A87 ç 455 505 Production method C 71.5 17 6 2.5 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 A88 AND 455 505 Production method E 75.5 17 5 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A89 AND 460 510 Production method E 73 18 6 0.5 0.1 0 0.4 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0
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TABLE 1-4
n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A90 AND 460 510 Production method E 70 18 7 2.5 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 A91 AND 455 505 Production method D 67 18 8 5 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A92 AND 465 515 Production method E 65.5 19 7 6.5 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A93 AND 465 515 Production method E 73 19 5 1 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A94 Ç 465 515 Production method E 65 19 8 4 0 0 1 0.5 0.5 0.5 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A95 Ç 465 515 Production method E 66 19 8 4 0 0 1 0.5 0.5 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A96 AND 465 515 Production method E 66.7 19 8 4 0 0 1 0 0 0.3 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A97 AND 465 515 Production method D 66.4 19 8 4 0 0 1 0 0.3 0.3 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A98 Ç 470 520 Production method D 69.8 20 8 0 0.2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A99 AND 470 520 Production method E 65.5 20 8 3.5 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A100 Ç 470 485 Production method A 65.5 20 8 3.5 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A101 Ç 470 520 Production method B 65.5 20 8 3.5 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A102 Ç 470 520 Production method C 65.5 20 8 3.5 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A103 AND 475 525 Production method E 65.9 21 9 1.5 1 0.4 0.2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A104 AND 470 520 Production method D 67 22 7 2 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A105 AND 460 510 Production method E 69.2 22 6 2 0.1 0 0 0 0 0 0.4 0 0 0 0 0 0 0 0 0.3 0 0 0 0 A106 AND 460 510 Production method D 69 22 6 2 0 0.1 0 0 0 0 0.4 0 0 0 0 0 0 0 0.2 0.3 0 0 0 0 A107 Ç 460 510 Production method E 69.05 22 6 2 0 0 0 0 0 0 0.4 0 0 0 0 0 0 0 0.25 0.3 0 0 0 0 A108 AND 470 520 Production method E 65.5 23 7 2 0 0 0.5 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 A109 AND 470 520 Production method E 68.5 23 4 2.5 0 0 0.3 0.2 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0 A110 Ç 475 525 Production method E 67.3 24 4 0.5 0 0 3.2 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B A111 AND 475 525 Production method E 65.5 24 3.5 3.5 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A112 AND 470 520 Production method E 66 24.5 4 3.5 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A113 AND 475 525 Production method E 65.7 24.5 3.5 4 0 0 0.2 0 0 0 1.6 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A114 AND 475 525 Production method E 65.3 24.5 3.5 3 0 0 1 0 0 0 2.4 0 0 0 0 0 0 0 0 0.3 0 0 0 0 A115 Ç 475 525 Production method D 65.6 24.5 3.5 3.5 0 0 0.1 0 0 0 2.5 0 0 0 0 0 0 0 0 0.3 0 0 0 0 A116 Ç 485 535 Production method D 61 24.5 12.5 1.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 A117 ç 460 510 Production method D 69.5 25 3 1.5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 A118 ç 465 515 Production method D 67.4 25 3.5 0.1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 A119 ç Commercially available Zn-AI-Mg based coating 85.7 11 3 0 0 0 0 0 0 0 0.2 0 0 0 0 0 0 0 0 0.1 0 0 0 0
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TABLE 1-5
n ° Category Total Determination specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula I I I I Sn- (Bi + ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 TO 1 Ç 0 0 0.8 0.1 1 0.01 1.3 - 0.4 882 NG A2 AND 0 0.4 5 0.4 5 0.06 11.9 0.05 0.5 3967 NG A3 AND 0 0.4 5 0.4 5 0.06 14.0 0.05 0.5 3864 NG A4 AND 0 0 2 0 2 0.02 2.1 0.4 <0.5 1263 NG A5 Ç 0 0.5 5 0.4 5 0.06 9.0 0.05 0.5 3765 NG A6 Ç 0 0.5 5 0.4 5 0.06 8.5 0.05 0.5 3864 NG A7 AND 0 0 20 0 20 0.29 11.5 1.99 <0.5 4392 NG A8 AND 0 0 1 0.1 1 0.01 3.3 0.13 0.5 1092 NG A9 Ç 0 0 1 0.1 1 0.01 1.4 - 0.5 984 NG A10 Ç 0 0 1 0.1 1 0.01 1.4 - 0.5 876 NG A11 ç 0 0 1 0.1 1 0.01 4.0 0.1 0.5 975 NG A12 AND 0 0.3 1 0.1 1 0.01 3.5 0.14 0.5 1013 NG A13 ç 0 0.6 1 0.1 1 0.01 3.8 0.13 0.4 1001 NG A14 AND 0 0 4 0 4 0.05 4.4 1.88 <0.5 3267 NG A15 Ç 0 0 0.2 0 -0.1 0.00 1.1 - <0.5 541 NG A16 AND 0 0.4 0.5 0 0.2 0.01 3.8 0.45 <0.5 534 OK A17 Ç 0 0.5 0.5 0 0.2 0.01 3.5 0.6 <0.5 561 NG A18 AND 0 0 1 0 0.7 0.01 3.8 1.25 <0.5 901 OK
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n ° Category Total Determination specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula I I I I Sn- (Bi-i-ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 A19 AND 0 0 2 0 1.7 0.02 5.0 1.42 <0.5 1345 OK A20 AND 0 0 5 0.03 5 0.06 6.5 0.3 <0.5 2885 NG A21 Ç 0 0 5 -0.65 5 0.06 6.9 0.2 <0.5 2902 NG A22 AND 0 0 0.1 0.05 0.1 0.00 2.1 0.28 0.9 508 NG A23 AND 0 0 0.3 3 0.3 0.00 2.5 0.03 5.3 609 NG A24 AND 0 0 0.5 3 0.5 0.01 2.5 0.03 5 721 NG A25 Ç 0 0 0.5 3 0.5 0.01 1.1 - 5 664 NG A26 Ç 0 0 0.5 3 0.5 0.01 1.3 - 5 618 NG A27 ç 0 0 0.5 3 0.5 0.01 2.9 0.03 5 632 NG A28 AND 0 0 4 0.5 4 0.05 4.6 0.04 0.8 4626 NG A29 AND 0 0 2 0.1 1.8 0.02 4.6 0.06 0.8 1756 OK A30 Ç 0 0 2 0.3 2 0.03 4.4 0.05 1 2625 NG
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TABLE 1-6
n ° Category Total Determination Specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula I I I I Sn- (Bi-i-ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 A31 AND 0 0 2 0.6 2 0.03 5.0 0.05 1 2354 NG A32 Ç 0 0 2 0.5 2 0.03 4.8 0.04 1 2367 NG A33 AND 0 0 2 0.6 2 0.03 4.6 0.04 1 2311 NG A34 AND 0 0 5 0 4.8 0.06 6.9 2.32 <0.5 3854 OK A35 AND 0.2 0 5 0 4.8 0.06 6.7 2.41 <0.5 3765 OK A36 Ç 0.25 0 5 0 4.8 0.06 1.4 - <0.5 3921 NG A37 AND 0 0 5 0 4.8 0.06 6.7 2.26 <0.5 3832 OK A38 AND 0.2 0 5 0 4.8 0.06 6.7 2.35 <0.5 3568 OK A39 Ç 0.25 0 5 0 4.8 0.06 1.3 - <0.5 3712 NG A40 Ç 0 0 -0.5 0 0 0.00 1.4 2 <0.5 230 NG A41 AND 0.1 0 0.4 0.4 0.5 0.01 3.3 0.05 1 601 OK A42 AND 0.1 0 2.9 0.4 3 0.04 3.5 0.05 0.8 3124 OK A43 AND 0.1 0 4.9 0.4 5 0.07 6.5 0.05 0.5 4256 OK A44 Ç 0 0 22 0.8 22 0.39 25.0 0.05 0.4 8012 NG A45 Ç 0 0 0 0 0.8 0.01 3.5 1.22 <0.5 911 NG A46 AND 0 0 0.4 0 0.8 0.01 3.5 1.34 <0.5 923 OK A47 AND 0 0 0.6 0.1 1 0.01 3.8 0.14 0.5 978 NG A48 AND 0 0 0.8 0.1 1 0.01 4.0 0.13 0.5 998 NG
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Petition 870190071281, of 7/25/2019, p. 120/194
n ° Category Total Determination Specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula I I I I Sn- (Bi-i-ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 A49 AND 0 0 5 0.3 5 0.07 5.2 0.06 0.4 4102 NG A50 AND 0.2 0 5 0.3 4.9 0.07 5.2 0.06 0.4 4203 OK A51 AND 0.2 0 5 0.3 4.9 0.07 5.2 0.07 0.4 4116 OK A52 AND 0.2 0 5 0.3 4.9 0.07 5.2 0.06 0.4 4153 OK A53 AND 0.2 0 5 0.3 4.9 0.07 5.2 0.05 0.4 4136 OK A54 Ç 0.3 0 5 0.3 4.9 0.07 1.3 - 0.4 4200 NG A55 AND 0 0.4 9.5 1.3 10 0.15 5.2 0.04 0.8 5214 NG A56 AND 0 0.4 10.5 1.4 11 0.17 20.8 0.04 0.5 5641 NG A57 Ç 0 0.5 10.5 1.4 11 0.17 22.9 0.04 0.4 5312 NG A58 AND 0 0 5 0.3 9 0.14 9.6 0.05 <0.5 4999 NG A59 AND 0 0 3 0.5 3 0.04 3.5 0.05 0.8 3365 NG
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Petition 870190071281, of 7/25/2019, p. 121/194
TABLE 1-7
n ° Category Total Determination specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula I I I I Sn- (Bi + ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 A60 Ç 0 0 3 0.5 3 0.04 1.4 - 0.8 3457 NG A61 Ç 0 0 3 0.5 3 0.04 1.4 - 0.8 3395 NG A62 Ç 0 0 3 0.5 3 0.04 3.1 0.05 0.8 3451 NG A63 AND 0.2 0 3 0.5 3 0.04 3.3 0.06 0.8 3645 NG A64 Ç 0.25 0 3 0.5 3 0.04 1.3 - 0.8 3612 NG A65 AND 0 0 3 0 3 0.04 3.5 1.96 <0.5 3015 NG A66 AND 0.2 0 3 0 3 0.04 4.0 1.92 <0.5 2768 NG A67 Ç 0.25 0 3 0 3 0.04 1.4 1.85 <0.5 2912 NG A68 Ç 0 0 0 0.5 5 0.08 5.2 0.06 0.4 4169 NG A69 ç 0 0 7 0.1 9 0.14 5.2 0.06 <0.5 4725 NG A70 AND 0 0 4 0.3 5 0.07 4.2 0.05 0.4 4654 NG A71 AND 0 0 5 2 5 0.08 16.7 0.03 0.7 4915 NG A72 Ç 0 0 0.05 0.5 0.05 0.00 1.1 0.05 5.2 215 NG A73 AND 0 0 4 0 4 0.05 5.2 2.32 <0.5 2367 NG A74 AND 0 0 5 0.5 5 0.08 4.6 0.05 0.5 4321 NG A75 AND 0.2 0 5 0.5 5 0.08 5.0 0.06 0.5 4356 NG A76 Ç 0.25 0 5 0.5 5 0.08 1.4 - 0.5 4159 NG A77 AND 0 0 6 0.5 6 0.09 15.2 0.05 <0.5 4465 NG
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Petition 870190071281, of 7/25/2019, p. 122/194
n ° Category Total Determination specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula I I I I Sn- (Bi-i-ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 A78 AND 0.2 0 6 0.5 6 0.09 15.2 0.06 <0.5 4458 NG A79 Ç 0.25 0 6 0.5 6 0.09 1.4 - <0.5 4396 NG A80 AND 0 0 5 0.5 5 0.08 13.8 0.05 <0.5 4267 NG A81 AND 0.2 0 5 0.5 5 0.08 12.9 0.05 <0.5 4314 NG A82 Ç 0.25 0 5 0.3 5 0.08 1.4 - <0.5 4004 NG A83 AND 0 0 2 0 2 0.03 2.5 1.74 <0.5 1932 NG A84 AND 0 0 2.5 1 2.5 0.03 2.9 1.58 1.9 2121 NG A85 Ç 0 0 2.5 1 2.5 0.03 1.4 - 1.8 2168 NG A86 Ç 0 0 2.5 1 2.5 0.03 1.4 - 1.8 2264 NG A87 ç 0 0 2.5 1 2.5 0.03 2.7 1.58 1.8 2545 NG A88 AND 0 0 1 0 1 0.01 2.5 1.7 <0.5 773 NG A89 AND 0 0 0.4 0.4 0.5 0.01 2.3 0.06 1 525 NG
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Petition 870190071281, of 7/25/2019, p. 123/194
TABLE 1-8
n ° Category Total Determination specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula I I I I Sn- (Bi + ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 A90 AND 0 0 2.5 0.5 2.5 0.04 3.3 0.04 0.8 3007 NG A91 AND 0 0 5 0.5 5 0.07 6.5 0.05 0.5 3913 NG A92 AND 0 0 6.5 0.5 6.5 0.10 22.9 0.05 <0.5 4915 NG A93 AND 0 0 0.5 0 1 0.01 3.8 1.6 <0.5 573 NG A94 Ç 0 0 4 -0.5 4 0.06 3.5 0.05 0.8 4426 NG A95 Ç 0 0 4 0 4 0.06 3.3 0.05 0.8 4515 NG A96 AND 0 0 4 0.7 4 0.06 3.5 0.05 0.8 4561 NG A97 AND 0 0 4 0.4 4 0.06 3.3 0.04 0.8 4712 NG A98 Ç 0 0 -0.2 1 0 0.00 1.0 0.05 <0.5 207 NG A99 AND 0 0 3.5 2 3.5 0.05 5.2 0.04 0.9 3715 NG A100 Ç 0 0 3.5 2 3.5 0.05 1.4 - 0.9 3385 NG A101 Ç 0 0 3.5 2 3.5 0.05 1.4 - 0.9 3451 NG A102 ç 0 0 3.5 2 3.5 0.05 5.2 4 0.9 3512 NG A103 AND 0 0 0.1 0.2 1.5 0.02 4.4 0.15 <0.5 1443 NG A104 AND 0 0 2 0.5 2 0.03 4.2 0.05 0.8 2176 NG A105 AND 0 0 1.9 0 1.6 0.03 4.0 1.58 <0.5 1521 OK A106 AND 0.2 0 1.9 0 1.6 0.03 3.8 1.62 <0.5 1347 OK A107 Ç 0.25 0 2 0 1.6 0.03 1.4 - <0.5 1159 NG
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Petition 870190071281, of 7/25/2019, p. 124/194
n ° Category Total Determination specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula I I I I Sn- (Bi-i-ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 A108 AND 0 0 2 0.5 2 0.03 2.5 0.05 0.8 1953 NG A109 AND 0 0 2.5 0.1 2.5 0.04 3.5 0.05 0.7 2124 NG A110 Ç 0 0 0.5 3.2 0.5 0.01 3.8 0.03 1 801 NG A111 AND 0 0 3.5 3 3.5 0.05 4.0 0.03 1 3125 NG A112 AND 0 0 3.5 1 3.5 0.05 4.8 0.03 0.8 3311 NG A113 AND 0 0 4 0.2 2.4 0.06 3.5 0.1 <0.5 4712 OK A114 AND 0 0 3 1 0.6 0.05 3.3 0.05 0.9 3315 OK A115 Ç 0 0 3.5 0.1 1 0.05 3.5 0.12 <0.5 3541 NG A116 Ç 0 0 1.5 0 1.5 0.02 2.3 1.65 <0.5 1024 NG A117 ç 0 0 1.5 0 1.5 0.02 2.5 1.25 <0.5 1100 NG A118 ç 0 0 0.1 0 0.1 0.00 1.1 - <0.5 340 NG A119 ç 0 0 0 0 -0.2 0.00 - - - 275 NG
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Petition 870190071281, of 7/25/2019, p. 125/194
TABLE 1-9
n ° Category Area fraction (%) Corrosion resistance Corrosion potential SST Dust Formation Stretch microsphere test Vickers Hardness (Hv) Zn +MCSB MCSB / Zn Massive MCSB Structure ofThin ZnAI Al MgZn2 Ternary eutectic structure Flat surface End surface White rust area Folding inV From workDc (pm) 1 cycle 5 cycles TO 1 Ç 0 - - 0 0 20 20 0 B B B -1 B AAA THE THE 190 A2 AND 10 35 0.1 5 0 40 40 0 THE AAA AAA -1.4 AAA AAA THE THE 150 A3 AND 10 35 0.1 5 0 40 40 0 THE AAA AAA -1.4 AAA AAA THE THE 150 A4 AND 5 40 0.1 0 0 45 45 0 THE AAA THE -1.3 THE AAA THE THE 170 A5 Ç 10 25 0.2 5 0 36 3 0 B AAA AAA -1.4 B B B THE 170 A6 Ç 10 35 0.2 5 0 40 2 0 B AAA AAA -1.4 B B B THE 170 A7 AND 10 60 0.2 15 0 42 30 0 THE AAA AA -1.5 THE AAA THE THE 150 A8 AND 25 15 0.1 0 5 40 28 0 THE AAA AA -1.3 AAA AAA THE THE 200 A9 Ç 0 - - 0 5 38 17 38 B B B -1.3 B B B THE 200 A10 Ç 0 - - 0 5 33 18 42 B B B -1.3 B AAA THE THE 200 A11 ç 0 - - 0 0 66 30 0 THE AAA AA -1.3 B B B THE 200 A12 AND 25 15 0.1 0 5 42 23 0 THE AAA AA -1.3 AAA AAA THE THE 200 A13 ç 25 15 0.1 0 4 21 23 0 B B B -1.3 B B B THE 200 A14 AND 20 35 0.2 3 5 28 38 0 THE AAA AA -1.4 THE AAA THE THE 210 A15 Ç 0 - - 0 4 26 37 0 B B B -1.2 THE AAA THE THE 210 A16 AND 30 40 0.2 0 5 25 38 0 THE THE THE -1.2 THE AAA THE THE 210 A17 Ç 30 40 0.2 0 5 21 30 0 B THE THE -1.2 B B B THE 210 A18 AND 30 15 0.1 0 5 24 38 0 THE THE THE -1.2 THE AAA THE THE 210
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Petition 870190071281, of 7/25/2019, p. 126/194
n ° Category Area fraction (%) Corrosion resistance Corrosion potential SST Dust Formation Stretch microsphere test Vickers Hardness (Hv) Zn +MCSB MCSB / Zn Massive MCSB Structure ofThin ZnAI Al MgZn2 Ternary eutectic structure Flat surface End surface White rust area Folding inV From workDc (pm) 1 cycle 5 cycles A19 AND 30 25 0.1 0 4 26 35 0 THE THE THE -1.2 THE AAA THE THE 210 A20 AND 25 35 0.1 5 5 28 36 0 THE AAA AA -1.4 THE AAA THE THE 200 A21 Ç 25 30 0.1 5 5 23 28 0 B AAA AAA -1.4 B B B THE 200 A22 AND 20 10 0.1 0 4 27 42 0 THE AAA AA -1.2 AAA AAA THE THE 250 A23 AND 20 10 0.1 0 5 27 42 0 THE AAA AA -1.2 AAA AAA THE THE 250 A24 AND 20 15 0.1 0 15 26 38 0 THE AAA AA -1.2 AAA AAA AAA THE 250 A25 Ç 0 - - 0 5 13 43 33 B B B -1.2 B B B THE 250 A26 Ç 0 - - 0 5 12 42 35 B B B -1.2 B AAA AAA THE 250 A27 ç 0 - - 0 0 53 38 0 B AAA AA -1.2 B B B THE 250 A28 AND 20 30 0.2 5 20 15 38 0 THE AAA AAA -1.4 AAA AAA AAA THE 250 A29 AND 25 25 0.1 0 10 27 33 0 THE THE AA -1.3 AAA AAA AAA THE 240 A30 Ç 25 25 0.1 0 15 22 23 0 B AAA AA -1.3 B B B THE 240
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Petition 870190071281, of 7/25/2019, p. 127/194
TABLE 1-10
n ° Category Area fraction (%) Corrosion resistance Corrosion potential SST Dust Formation Stretch microsphere test Vickers Hardness (Hv) Zn +MCSB MCSB / Zn Massive MCSB Structure ofThin ZnAI Al MgZn2 Ternary eutectic structure Flat surface End surface White rust area Folding inV From workDc (pm) 1 cycle 5 cycles A31 AND 25 25 0.1 0 10 25 37 0 THE AAA AA -1.3 AAA AAA AAA THE 240 A32 Ç 25 25 0.1 0 5 24 30 0 B AAA AA -1.3 B B B THE 240 A33 AND 25 25 0.1 0 5 28 38 0 THE AAA AA -1.3 AAA AAA THE THE 240 A34 AND 25 25 0.1 5 5 24 37 0 THE THE AA -1.4 THE AAA THE THE 220 A35 AND 25 25 0.1 5 5 28 33 0 THE THE AA -1.5 THE AAA THE THE 220 A36 Ç 0 - - 5 5 32 36 0 B B B -1.1 B B B THE 220 A37 AND 25 35 0.2 5 5 28 35 0 THE THE AA -1.4 THE AAA THE THE 220 A38 AND 25 35 0.2 5 5 25 36 0 THE THE AA -1.5 THE AAA THE THE 220 A39 Ç 0 - - 0 5 34 36 0 B B B -1.1 B B B THE 220 A40 Ç 0 - - 0 5 34 37 0 B AAA THE -1.4 B B B THE 280 A41 AND 25 10 0.1 0 5 24 37 0 THE AAA AA -1.3 AAA AAA THE THE 250 A42 AND 25 25 0.1 0 5 24 38 0 THE AAA AA -1.4 AAA AAA THE THE 240 A43 AND 25 40 0.2 5 5 29 34 0 THE AAA AAA -1.5 AAA AAA THE THE 230 A44 Ç 15 55 0.2 20 5 54 0 0 B AAA AAA -1.4 B AAA THE THE 150 A45 Ç 25 15 0.1 0 5 30 33 0 B THE THE -1.3 B B B THE 220 A46 AND 25 15 0.1 0 10 33 28 0 THE THE THE -1.3 THE AAA AAA THE 260 A47 AND 25 15 0.1 0 15 34 23 0 THE AAA AA -1.3 AAA AAA AAA THE 250 A48 AND 25 15 0.1 0 10 34 23 0 THE AAA AA -1.3 AAA AAA AAA THE 250
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Petition 870190071281, of 7/25/2019, p. 128/194
n ° Category Area fraction (%) Corrosion resistance Corrosion potential SST Dust Formation Stretch microsphere test Vickers Hardness (Hv) Zn +MCSB MCSB / Zn Massive MCSB Structure ofThin ZnAI Al MgZn2 Ternary eutectic structure Flat surface End surface White rust area Folding inV From workDc (pm) 1 cycle 5 cycles A49 AND 20 35 0.2 7 5 32 28 0 THE AAA AAA -1.4 THE AAA AAA THE 260 A50 AND 20 35 0.2 8 10 30 26 0 THE AA AAA -1.5 THE AAA AAA THE 260 A51 AND 20 35 0.2 7 5 30 26 0 THE AA AAA -1.5 THE AAA THE THE 260 A52 AND 20 35 0.2 8 15 29 25 0 THE AA AAA -1.5 THE AAA AAA THE 260 A53 AND 20 35 0.2 7 10 30 24 0 THE AA AAA -1.5 THE AAA AAA THE 260 A54 Ç 0 - - 0 10 25 27 0 B B B -1.1 B B B THE 260 A55 AND 15 50 0.2 10 15 20 37 0 THE AAA AAA -1.4 AAA AAA AAA THE 270 A56 AND 15 50 0.2 13 15 20 35 0 THE AAA AAA -1.4 AAA AAA AAA THE 270 A57 Ç 15 50 0.2 18 10 18 34 0 B AAA AAA -1.4 B B B THE 270 A58 AND 20 45 0.2 12 10 16 38 0 THE AAA AAA -1.4 THE AAA AAA THE 270 A59 AND 20 30 0.2 0 5 28 39 0 THE AAA AA -1.3 AAA AAA THE THE 260
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Petition 870190071281, of 7/25/2019, p. 129/194
TABLE 1-11
n ° Category Area fraction (%) Corrosion resistance Corrosion potential SST Dust Formation Stretch microsphere test Vickers Hardness (Hv) Zn +MCSB MCSB / Zn Massive MCSB Structure ofThin ZnAI Al MgZn2 Ternary eutectic structure Flat surface End surface White rust area Folding inV From workDc (pm) 1 cycle 5 cycles A60 Ç 0 - - 0 5 30 40 0 B B B -1.3 B B B THE 260 A61 Ç 0 - - 0 5 35 37 0 B B B -1.3 B AAA THE THE 260 A62 Ç 0 - - 0 0 77 20 0 THE AAA AA -1.3 B B B THE 260 A63 AND 20 25 0.1 0 5 32 40 0 THE AAA AA -1.4 AAA AAA THE THE 260 A64 Ç 0 - - 0 5 37 34 0 B B B -1.1 B B B THE 260 A65 AND 20 25 0.1 0 10 33 35 0 THE AAA THE -1.3 THE AAA AAA THE 260 A66 AND 20 25 0.1 0 5 30 36 0 THE AAA THE -1.4 THE AAA THE THE 260 A67 Ç 0 - - 0 5 34 40 0 B B B -1.1 B B B THE 260 A68 Ç 15 25 0.1 12 5 47 3 0 B AAA AAA -1.4 B B B THE 280 A69 ç 15 25 0.1 13 5 45 2 0 B AAA AAA -1.4 B B B THE 280 A70 AND 15 35 0.2 5 5 30 41 0 THE AAA AAA -1.4 THE AAA THE THE 280 A71 AND 15 35 0.2 20 5 12 44 0 THE AAA AAA -1.4 AAA AAA THE THE 310 A72 Ç 20 10 0.1 0 5 3 38 33 B AAA AA -1.1 B AAA THE THE 300 A73 AND 35 35 0.2 5 5 33 18 0 THE AAA AA -1.3 THE AAA THE THE 250 A74 AND 20 40 0.2 5 5 12 56 0 THE AAA AA -1.4 AAA AAA THE THE 300 A75 AND 20 35 0.2 6 5 10 55 0 THE AAA AA -1.5 AAA AAA THE THE 300 A76 Ç 0 - - 0 5 8 56 0 B B B -1.1 B B B THE 300 A77 AND 20 40 0.2 12 5 10 50 0 THE AAA AAA -1.4 THE AAA THE THE 300
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Petition 870190071281, of 7/25/2019, p. 130/194
n ° Category Area fraction (%) Corrosion resistance Corrosion potential SST Dust Formation Stretch microsphere test Vickers Hardness (Hv) Zn +MCSB MCSB / Zn Massive MCSB Structure ofThin ZnAI Al MgZn2 Ternary eutectic structure Flat surface End surface White rust area Folding inV From workDc (pm) 1 cycle 5 cycles A78 AND 20 45 0.2 13 5 9 52 0 THE AAA AAA -1.5 THE AAA THE THE 300 A79 Ç 0 40 0.2 0 5 5 56 0 B B B -1.1 B B B THE 300 A80 AND 15 40 0.2 13 5 14 43 0 THE AAA AAA -1.4 THE AAA THE THE 310 A81 AND 15 40 0.2 0 5 12 63 0 THE AAA AA -1.5 THE AAA THE THE 310 A82 Ç 0 40 0.2 0 5 16 49 0 B B B -1.1 B B B THE 310 A83 AND 30 20 0.1 0 5 40 19 0 THE AAA THE -1.3 THE AAA THE THE 280 A84 AND 35 25 0.1 0 5 31 26 0 THE AAA THE -1.3 AAA AAA THE THE 280 A85 Ç 0 - - 0 5 32 40 15 B B B -1.3 B B B THE 280 A86 Ç 0 - - 0 5 33 42 12 B B B -1.3 B AAA THE THE 280 A87 ç 0 - - 0 0 69 21 0 THE AAA THE -1.3 B B B THE 280 A88 AND 30 15 0.1 0 10 15 42 0 THE AAA THE -1.2 THE AAA AAA THE 290 A89 AND 30 10 0.1 0 10 16 40 0 THE AAA AA -1.2 AAA AAA AAA THE 300
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Petition 870190071281, of 7/25/2019, p. 131/194
TABLE 1-12
n ° Category Area fraction (%) Corrosion resistance Corrosion potential SST Dust Formation Stretch microsphere test Vickers Hardness (Hv) Zn +MCSB MCSB / Zn Massive MCSB Structure ofThin ZnAI Al MgZn2 Ternary eutectic structure Flat surface End surface White rust area Folding inV From workDc (pm) 1 cycle 5 cycles A90 AND 25 30 0.2 0 20 18 35 0 THE AAA AA -1.3 AAA AAA AAA THE 300 A91 AND 20 35 0.2 3 5 20 45 0 THE AAA AA -1.4 AAA AAA THE THE 290 A92 AND 25 35 0.2 12 15 18 28 0 THE AAA AAA -1.4 THE AAA AAA THE 290 A93 AND 30 25 0.1 0 10 20 35 0 THE AAA THE -1.2 THE AAA AAA THE 290 A94 Ç 20 30 0.2 6 10 19 41 0 B AAA AA -1.3 B B B THE 300 A95 Ç 20 30 0.2 6 10 19 41 0 B AAA AA -1.3 B B B THE 300 A96 AND 20 30 0.2 5 10 18 42 0 THE AAA AA -1.3 AAA AAA AAA THE 300 A97 AND 20 30 0.2 6 5 20 43 0 THE AAA AA -1.3 AAA AAA THE THE 300 A98 Ç 0 - - 0 5 23 43 0 THE AAA AA -1.4 THE B B THE 320 A99 AND 20 30 0.2 10 15 15 38 0 THE AAA AAA -1.4 AAA AAA AAA THE 300 A100 Ç 0 30 0.2 0 5 31 40 6 B B B -1.4 B B B THE 300 A101 Ç 0 30 0.2 0 5 26 41 5 B B B -1.4 B AAA AAA THE 300 A102 ç 0 30 0.2 10 0 79 9 0 THE AAA AA -1.4 B B B THE 300 A103 AND 20 25 0.1 0 10 18 50 0 THE AAA AA -1.4 THE AAA AAA THE 310 A104 AND 30 25 0.1 0 5 18 45 0 THE AAA AA -1.3 AAA AAA THE THE 300 A105 AND 30 25 0.1 0 10 20 38 0 THE THE AA -1.3 THE AAA AAA THE 290 A106 AND 30 25 0.1 0 5 23 38 0 THE THE AA -1.4 THE AAA THE THE 290 A107 Ç 0 25 0.1 0 15 29 33 0 B B B -1.1 B B B THE 290
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Petition 870190071281, of 7/25/2019, p. 132/194
n ° Category Area fraction (%) Corrosion resistance Corrosion potential SST Dust Formation Stretch microsphere test Vickers Hardness (Hv) Zn +MCSB MCSB / Zn Massive MCSB Structure ofThin ZnAI Al MgZn2 Ternary eutectic structure Flat surface End surface White rust area Folding inV From workDc (pm) 1 cycle 5 cycles A108 AND 15 25 0.1 0 15 20 46 0 THE AAA AA -1.3 AAA AAA AAA THE 300 A109 AND 20 25 0.1 0 25 18 36 0 THE AAA AA -1.3 AAA AAA AAA THE 200 A110 Ç 15 15 - 0 15 28 16 0 B AAA AA -1.3 B B B THE 300 A111 AND 15 35 0.2 5 15 55 2 0 THE AAA AAA -1.4 AAA AAA AAA THE 190 A112 AND 15 35 0.2 7 10 56 3 0 THE AAA AAA -1.4 AAA AAA AAA THE 190 A113 AND 10 35 0.2 6 20 57 1 0 THE THE AAA -1.4 THE AAA AAA THE 180 A114 AND 10 35 0.2 0 15 62 2 0 THE THE AA -1.4 AAA AAA AAA THE 190 A115 Ç 10 35 0.2 8 5 59 9 0 THE B AAA -1.4 THE AAA THE THE 190 A116 Ç 10 20 0.1 0 5 18 62 0 THE THE THE -1.2 THE B THE THE 350 A117 ç 10 15 0.1 0 5 71 6 0 THE B B -1.1 THE B B THE 220 A118 ç 0 - - 0 5 81 5 0 B B B -1.1 B B B THE 220 A119 ç 0 - - 0 0 37 9 52 B B B -1 B AAA AAA THE 150
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Petition 870190071281, of 7/25/2019, p. 133/194
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EXAMPLE Β [00453] In order to obtain coating layers for the chemical compositions shown in Table 2-1, a given amount of pure metal ingot was used for preparation and melted in a vacuum melting furnace, followed by the initial bath composition coating in the air. For the preparation of coated steel sheets, a batch type melting coating system was used. General cold-rolled carbon steel 0.8 mm (C <0.1% concentration) was used for a base coat plate, and degreasing and pickling were carried out immediately before the coating step.
[00454] In any sample preparation, the same reduction treatment method was applied to the base coat plate until immersion in the coating bath. In other words, the base coat plate was heated from room temperature to 800 Ό by electric heating in an environment of N ₂ -H ₂ (5%) (dew point of -40 Ό or less, the oxygen concentration less than 25 ppm), maintained for 60 seconds, cooled to the coating bath temperature of + 10 Ό by spraying N ₂ gas, and immediately immersed in the coating bath.
[00455] The coating process was conducted according to production method D described above for production.
[00456] Controlling the immersion time of the coating bath, steel sheets coated with different thicknesses of the Al-Fe alloy layer were prepared. In addition, the amount of cleaning gas was adjusted to prepare steel sheets coated with different thicknesses of the Zn-AI-Mg alloy layer. As in (Example A), several analyzes and measurements were conducted.
POWDER FORMATION [00457] To assess the processability of the coating layerPetition 870190071281, dated 07/25/2019, p. 134/194
127/144 to, each coated steel sheet was subjected to a bending test of
The R-90 ° and cellophane tape having a width of 24 mm was pressed against and removed from a V-shaped valley fold in order to visually judge the dust.
[00458] A case in which the powder exfoliated due to the powder was adhered in lines to the tape was evaluated as B.
[00459] A case in which the powder exfoliated due to the spray adhered in points to the tape was evaluated as A.
[00460] A case in which powder exfoliation did not occur was assessed as AAA.
TEST salt spray (AS SST WRITTEN IN TABLES) [00461] A layer of Zn-Al-Mg is removed from the surface of the coating layer surface processing cutter for Examples ^Nos 1 to 12. These layers coated steel, in which only the Al-Fe alloy layer was bonded, was subjected to a salt spray test (J IS Z 2371) in order to measure the fraction of the red rust area of the coating surface after 24 hours. The approval criteria were determined on the basis of cold rolled carbon steel used as a comparative material for a base coat plate, a red rust fraction of 90% or more indicating that an increase in the red rust fraction was rated as B, and a fraction of red rust area less than 90% was assessed as AAA.
[00462] Tables 2-1 to 2-3 show lists from example B.
Petition 870190071281, of 7/25/2019, p. 135/194
TABLE 2-1
n ° Category Coating bath melting point Coating bath temperature Immersion Production method Component (% by mass) time Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) (Mon.) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B B1 AND 375 500 0.5 Production method D 79 6 4.5 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 B2 AND 375 500 2 Production method D 79 6 4.5 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 B3 AND 375 500 3 Production method D 79 6 4.5 10 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.5 0 0 0 0 B4 AND 410 500 3 Production method D 83.2 10 4.5 1 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 1 0 0 0 0 B5 AND 410 500 3 Production method D 83.2 10 4.5 1 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 1 0 0 0 0 B6 AND 410 500 3 Production method D 83.2 10 4.5 1 0 0 0 0 0 0 0.3 0 0 0 0 0 0 0 0 1 0 0 0 0 B7 AND 430 500 3 Production method D 77 13 6 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 B8 AND 450 500 3 Production method D 74.9 17 5 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0.1 B9 AND 460 510 3 Production method D 69.1 20 7 2 0 0 0.4 0 0 0 0 0 0 0 0 0 0 0 0 1.5 0 0 0 0
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n ° Category Coating bath melting point Coating bath temperature Immersion Production method Component (% by mass) time Sn Group Ca GroupCr GroupSr Group (Ό) (Ό) (Mon.) Zn Al Mg Sn Bi In Here Y Over there Ce Si Cr You Ni Co V Nb Ass Mn Faith Mr Sb Pb B B10 AND 460 510 3 Production method D 68.6 20 7 2 0 0 0.4 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 B11 AND 460 510 7 Production method D 65.6 20 7 2 0 0 0.4 0 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 B12 Ç 460 510 9 Production method D 65.1 20 7 2 0 0 0.4 0 0 0 0 0 0 0 0 0 0 0 0 5.5 0 0 0 0 B13 Ç General carbon steel 100 -
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TABLE 2-2
n ° Category Total Determination Coating layer specific intensity Intensity Diffraction peak position Cr Group Sr Group Concentration formula Al-Fe bed Zn-AI- layerMg I I I I Sn (Bi + ln) Ca (Y + La + Ce) Sn-Si Sn / Zn (pm) (pm) (MCSB) (MgCaSn) (CaZnAI) (23.3j 23.36-23.46 B1 AND 0 0 10 0 10 0.13 0.10 25 8.5 1.99 <0.4 4399 NG B2 AND 0 0 10 0 10 0.13 1.50 25 9.7 1.95 <0.4 4562 NG B3 AND 0 0 10 0 10 0.13 2.00 25 8.4 1.93 <0.4 4881 NG B4 AND 0 0 1 0 0.7 0.01 2.00 3 3.3 1.2 <0.4 901 OK B5 AND 0 0 1 0 0.7 0.01 2.00 50 3.1 1.25 <0.4 995 OK B6 AND 0 0 1 0 0.7 0.01 2.00 95 3.6 1.25 <0.4 945 OK B7 AND 0 0 3 0 3 0.04 2.00 25 4.7 1.96 <0.4 3645 NG B8 AND 0 0.1 2 0 2 0.03 2.00 25 4.6 1.74 <0.4 1936 NG B9 AND 0 0 2 0.4 2 0.03 2 25 5 0.05 0.8 2985 NG B10 AND 0 0 2 0.4 2 0.03 3 25 4.9 0.05 0.8 3024 NG B11 AND 0 0 2 0.4 2 0.03 5 25 5.1 0.05 0.8 3112 NG B12 Ç 0 0 2 0.4 2 0.03 5.5 25 5.3 0.05 0.8 3215 NG B13 Ç - - - - - - - - - - - - -
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TABLE 2-3
n ° Category Area fraction Dust formation SST Zn + MCSC MCSC / Zn Massive MCSB Thin Zn-AI structure Al MgZn2 Ternary eutectic structure 0R-90 ° Evaluation of red rustDc (pm) B1 AND 10 60 0.2 0 0 60 25 0 AAA - B2 AND 10 55 0.2 0 0 60 25 0 THE AAA B3 AND 10 60 0.2 0 0 58 27 0 THE AAA B4 AND 25 15 0.1 0 5 40 28 0 AAA AAA B5 AND 30 15 0.1 0 5 38 29 0 THE AAA B6 AND 30 15 0.1 0 5 39 30 0 THE AAA B7 AND 20 25 0.1 0 5 30 36 0 AAA AAA B8 AND 30 25 0.1 0 5 33 33 0 AAA AAA B9 AND 30 25 0.1 0 5 33 33 0 AAA AAA B10 AND 30 25 0.1 0 5 18 45 0 THE AAA B11 AND 30 25 0.1 0 5 20 45 0 THE AAA B12 Ç 30 25 0.1 0 5 20 45 0 B AAA B13 Ç - - - - B
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EXAMPLE C [00463] In order to obtain coating layers of chemical compositions shown in Table 3-1, a given amount of pure metal ingot was used and melted in a vacuum melting furnace, followed by the initial composition of the coating bath up in the air. For the preparation of coated steel sheets, a batch type melting coating system was used. used 0.8 mm hot-rolled carbon steel (C concentration <0.1%) was used for a coating substrate, and degreasing and stripping were carried out just before the coating step.
[00464] In any sample preparation, the same reduction treatment method was applied to the base coat plate until immersion in the coating bath. In other words, the base coat plate was heated from room temperature to 800 Ό by electric heating in an environment of N2 -H2 (5%) (dew point of -40 Ό or less, the oxygen concentration of less than 25 ppm), maintained for 60 seconds, cooled to the coating bath temperature of + 10 Ό by spraying N2 gas, and immediately immersed in the coating bath. The thickness of each coating layer was adjusted to 30 pm.
[00465] The coating process was conducted according to the production method D or E described above for production.
[00466] Some samples were prepared using a 0.8 mm base coat sheet under the same conditions as Example A.
[00467] For all samples obtained, as in Example A, several analyzes, several measurements and evaluations were performed. Note that X-ray diffraction analysis was not performed.
[00468] Confirmation of the phase of the Ca-AISi intermetallic compound and the phase of the Mg-AI-Si intermetallic compound and the measurement of
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[00469] A 10 x 10 mm square was cut from each resulting coated steel sheet. The surface of the coating layer was embedded in a resin with an inclination of 10 ° in relation to the horizontal plane and polished, and the structure in oblique section of the coating layer was observed. In a case where an optional section was examined to find the amorphous or needle-like intermetallic compound phase and the metallic compound phase was confirmed, the element mapping analysis was additionally performed by EDS. In a case in which the presence of three elements, Ca, Al and Si, was confirmed, it was considered that there was the Ca-AI-Si intermetallic compound phase, and it was written as OK in the Presence column of the Ca- AI-Si in Table 3. In a case where the presence of three elements, Mg, Al and Si, was confirmed, it was considered that there was the Mg-AI-Si intermetallic compound phase, and it was written as OK in Presence column of Mg-AI-Si in Table 3.
[00470] Furthermore, in a case where the presence of the Ca-AI-Si intermetallic compound phase and the presence of the Mg-AI-Si intermetallic compound phase were confirmed, the average grain size of each of the phases of the intermetallic compound was measured according to the method described above. The results were presented in the Dc of Ca-AI-Si and Dc of Mg-AI-Si columns in Table 3.
[00471] In addition, to assess the corrosion resistance of the processed portion, each coated steel sheet was cut to a size of 30 x 60 x 0.8 mm, from which the 0T, 1T flexural specimens, 2T, 4T and 8T were prepared. In addition, the 30 x 60 mm flat specimens and these T-bend specimens (upper outside) were simultaneously subjected to a salt spray test (JIS Z 2371), and the accelerated corrosion test continued until red rust spots appear on the flat surface and the upper part
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134/144 rior. The rate of deterioration of the corrosion resistance of the processed portion defined by the following Formula was calculated for each of the OT flexion specimens at 8T: (rate of deterioration of the corrosion resistance of the processed portion) = (upper part of the test body bending time T) / (time to form red rust on the flat surface).
[00472] A rate of deterioration of the corrosion resistance of the processed portion of 0.8 or more for each of the 0 to 8T samples was assessed as AAA.
[00473] A rate of deterioration of the corrosion resistance of the processed portion of 0.8 or more only for samples 1T to 8T was evaluated as AA.
[00474] A rate of deterioration of the corrosion resistance of the processed portion of 0.8 or more only for samples 2T to 8T was evaluated as A +.
[00475] A rate of deterioration of the corrosion resistance of the processed portion of 0.8 or more only for samples 4T to 8T was evaluated as A.
[00476] A rate of deterioration of the corrosion resistance of the processed portion of 0.8 or more only for the 8T sample was evaluated as B.
[00477] Tables 3-1 to 3-3 show lists from Example C.
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TABLE 3-1
n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Determination Sn Group Ca Group Concentration formula (<C) (<C) Zn Al Vlg Sn Bi In Here Y Over there Ce Si Faith Sn- (Bi-i-ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn C1 AND 370 500 Production method D 87.5 5.5 4 2 0 0 0 0 0 0 0 0 2 0 2 0.02 C2 AND 370 500 Production method D 87.98 5.5 4 2 0 0 0 0 0 0 0 0 2 0 2 0.02 C3 AND 400 500 Production method D 79.7 10 6 4 0 0 0 0 0 0 0 0 4 0 4 0.05 C4 AND 400 500 Production method D 79.6 10 6 4 0 0 0 0 0 0 0 0 4 0 4 0.05 C5 AND 420 500 Production method D 81.85 11 6 0.1 0 0 0 0 0 0 0 0 0.1 0 0.1 0.00 C6 AND 415 500 Production method D 81.2 11 5.5 0.5 0.1 0 0 0 0 0 0 0 0.4 0 0.5 0.01 C7 AND 430 500 Production method D 76.8 13 6 3 0 0 0 0 0 0 0 0 3 0 3 0.04 C8 AND 430 500 Production method D 75.1 13 6 3 0 0 0 0 0 0 0 0 3 0 3 0.04 C9 AND 440 500 Production method D 73.5 16 5 4 0 0 0 0 0 0 0 0 4 0 4 0.05 C10 AND 440 500 Production method D 73 16 5 4 0 0 0 0 0 0 0 0 4 0 4 0.05
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n ° Category Coating bath melting point Coating bath temperature Production method Component (% by mass) Determination Sn Group Ca Group Concentration formula (<C) (<C) Zn Al Vlg Sn Bi In Here Y Over there Ce Si Faith Sn- (Bi-i-ln) Ca- (Y + La + Ce) Sn-Si Sn / Zn C11 AND 450 500 Production method D 75 17 5 2 0 0 0 0 0 0 0 0 2 0 2 0.03 C12 AND 450 500 Production method D 74.6 17 5 2 0 0 0 0 0 0 0 0 2 0 2 0.03 C13 AND 455 505 Production method D 67 18 8 5 0 0 0 0 0 0 0 0 5 0 5 0.07 C14 AND 455 505 Production method D 66.5 18 8 5 0 0 0 0 0 0 0 0 5 0 5 0.08 C15 AND 465 515 Production method E 73 19 5 1 0 0.5 0 0 0 0 0 0 0.5 0 1 0.01 C16 AND 465 515 Production method E 72.8 19 5 1 0 0.5 0 0 0 0 0 0 0.5 0 1 0.01 C17 AND 460 510 Production method D 69 22 6 2 0 0.1 0 0 0 0 0 0 1.9 0 2 0.03 C18 AND 460 510 Production method D 68.8 22 6 2 0 0.1 0 0 0 0 0 0 1.9 0 2 0.03 C19 AND 470 520 Production method E 66 24.5 4 3.5 0 0 0 0 0 0 0 0 3.5 0 3.5 0.05 C20 AND 470 520 Production method E 63.6 24.5 4 3.5 0 0 0 0 0 0 0 0 3.5 0 3.5 0.06
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TABLE 3-2
n ° Category Area fraction (%) Ternary eutectic structure Zn + MCSC MCSC / Zn Massive MCSB Thin ZnAI structure Al MgZn2 Ternary eutectic structure Ca-AI-Si Mg-AI-SiDc (pm) Presence Dc (pm) Presence Dc (pm) C1 AND 5 40 1 0 0 45 45 0 NG - NG - C2 AND 5 40 1 0 0 43 43 0 OK 1 OK 1 C3 AND 20 35 2 3 5 28 38 0 NG - NG - C4 AND 20 35 2 3 5 25 36 0 OK 2 OK 1 C5 AND 20 10 1 0 4 27 42 0 NG - NG - C6 AND 25 10 1 0 5 24 37 0 NG - NG - C7 AND 20 25 1 0 5 30 36 0 NG - NG - C8 AND 20 25 1 0 5 30 34 0 OK 4 OK 3 C9 AND 35 35 2 5 5 33 18 0 NG - NG - C10 AND 35 35 2 5 5 32 16 0 OK 3 OK 1 C11 AND 30 20 1 0 5 40 19 0 NG - NG - C12 AND 30 20 1 0 5 40 18 0 OK 2 OK 1 C13 AND 20 35 2 3 5 20 45 0 NG - NG - C14 AND 20 35 2 3 5 20 43 0 OK 4 OK 2 C15 AND 30 25 1 0 10 20 35 0 NG - NG - C16 AND 30 25 1 0 10 20 33 0 OK 2 OK 1 C17 AND 30 25 1 0 5 23 38 0 NG - NG - C18 AND 30 25 1 0 5 23 35 0 OK 3 OK 2 C19 AND 15 35 2 7 10 56 3 0 91 - NG - C20 AND 15 35 2 5 10 56 3 0 OK 5 OK 3
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TABLE 3-3
n ° Category Corrosion resistance Corrosion potential SST Dust formation Stretch microsphere test Vickers Hardness(Hv) Piano surface End surface Processed portion White rust area V-folding Unfolding 1 cycle 5 cycles C1 AND THE AAA THE A + -1.3 THE AAA THE THE 170 C2 AND THE AA THE AA -1.3 THE AAA THE THE 170 C3 AND THE AAA AA THE -1.4 THE AAA THE THE 210 C4 AND THE AA AAA AAA -1.4 THE AAA THE THE 210 C5 AND THE AAA AA A + -1.2 AAA AAA THE THE 250 C6 AND THE AAA AA A + -1.3 AAA AAA THE THE 250 C7 AND THE AAA THE A + -1.4 THE AAA THE THE 260 C8 AND THE THE AA AAA -1.4 AAA AAA THE THE 260 C9 AND THE AAA AA THE 0 THE AAA THE THE 250 C10 AND THE THE AAA AA -1.3 THE AAA THE THE 250 C11 AND THE AAA THE A + -1.3 THE AAA THE THE 280 C12 AND THE THE AA AAA -1.3 THE AAA THE THE 280 C13 AND THE AAA AA THE -1.4 AAA AAA THE THE 290 C14 AND THE THE AAA AA -1.4 AAA AAA THE THE 290 C15 AND THE AAA THE A + -1.2 THE AAA AAA THE 290 C16 AND THE AA AA AAA -1.2 THE AAA AAA THE 290 C17 AND THE THE AA A + -1.4 THE AAA THE THE 290 C18 AND THE THE AAA AAA -1.4 THE AAA THE THE 290 C19 AND THE AAA AAA THE -1.4 AAA AAA AAA THE 190 C20 AND THE THE AAA AA -1.4 THE AAA AAA THE 190
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[00478] The preferred embodiments of the invention have been described in detail with reference to the accompanying drawings. However, the invention is not limited to these examples. It is obvious that those skilled in the art to which the invention belongs can conceive of various changes or modifications within the scope of the technical concept described in the claims. It is obviously understood that these changes or modifications also fall within the technical scope of the invention.
[00479] In Figures 1 to 14, each reference numeral refers to the corresponding subject as described below.
[00480] 1: Al phase (including a thin Zn phase) [00481] 2: MgZn ₂ phase (massive) [00482] 3: ternary eutectic structure of Zn-AI-MgZn ₂ [00483] 4: phase Zn containing an Mg-Sn [00484] 5 intermetallic compound phase: Al [00485] 6: MgZn ₂ [00486] phase 7: Zn phase containing an Mg-Sn [00487] intermetallic compound phase 8 : Mg-Sn intermetallic compound phase that has a grain size of 1 pm or more (massive MgSn intermetallic compound phase) [00488] 9: eutectoid structure that has a lamellar spacing less than 300 nm composed of a Zn phase and an Al phase (thin Zn-AI eutectoid structure) [00489] 11: Mg-AI-Si intermetallic compound phase [00490] 12: Ca-AI-Si intermetallic compound phase [00491] 13: phase amorphous intermetallic compound (Mg-AI-Si intermetallic compound phase) [00492] 14: needle-type intermetallic compound phase (Ca-AI-Si intermetallic compound phase)
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140/144 [00493] 20: Zn phase that has a ternary eutectic structure of
Zn-AI-MgZn2 [00494] 21: MgZnz phase that has a ternary eutectic structure of Zn-AI-MgZn2 [00495] 22: Al phase that has a ternary eutectic structure of
Zn-AI-MgZn2 [00496] 30: Zn phase that has a ternary eutectic structure of
Zn-AI-MgZn2 [00497] 31: Al phase that has a ternary eutectic structure of
Zn-AI-MgZn2 [00498] 100: coating layer [00499] 100A: coating layer [00500] 101: Zn-AI-Mg alloy layer [00501] 101 A: Zn-AI-Mg alloy layer [00502] 102: Al-Fe alloy layer [00503] 102A: Al-Fe alloy layer [00504] In the disclosure, the following Additional Statements are still disclosed.
ADDITIONAL DECLARATION 1 [00505] A melt-coated steel sheet that has a steel product and a coating layer including a layer of Zn-AI-Mg alloy, arranged on the surface of the steel product;
[00506] in which a Zn phase in the Zn-AI-Mg alloy layer contains an intermetallic compound (Mg, Ca, Y, Lá, Ce) 2 (Sn, Bi, In), [00507] the coating layer consists of [00508] Zn: more than 65.0%, [00509] Al: from more than 5% to less than 25.0%, [00510] Mg: from more than 3% to less than 12.5%, [00511] Sn: from 0.10% to 20%, [00512] Bi: from 0% to less than 5%,
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141/144 [00513] In: from 0% to less than 2%, [00514] Ca: from 0% to 3.0% [00515] Y: from 0% to 0.5% [00516] La: from 0 % less than 0.5%, [00517] Ce: from 0% to less than 0.5%, [00518] Si: from 0% to less than 2.5%, [00519] Cr: from 0% to less than 0.25% [00520] Ti: from 0% to less than 0.25% [00521] Ni: from 0% to less than 0.25% [00522] Co: from 0% to less than 0.25 % [00523] V: from 0% to less than 0.25% [00524] Nb: from 0% to less than 0.25%, [00525] Cu: from 0% to less than 0.25% [00526] Mn: from 0% to less than 0.25% [00527] Fe: from 0% to 5% [00528] Sr: from 0% to less than 0.5%, [00529] Sb: from 0% to less than 0.5%, [00530] Pb: from 0% to less than 0.5%, [00531] B: from 0% to less than 0.5% in terms of percentage (%) by mass and impurities, and [ 00532] Bi + In <Sn, Y + La + Ce <Ca, Si <Sn, Cr + Ti + Ni + Co + V + Nb + Cu + Mn <0.25, and Sr + Sb + Pb + B <0 , 5 are satisfied.
ADDITIONAL DECLARATION 2 [00533] Steel sheet coated by melting according to Additional Declaration 1, in which the intermetallic compound (Mg, Ca, Y, La, Ce) 2 (Sn, Bi, In) has a grain size less than 1 pm and is dispersed in the Zn phase.
ADDITIONAL DECLARATION 3 [00534] The steel sheet coated by melting according to Additional Declaration 1 or 2, in which the Zn phase containing the compound inPetição 870190071281, of 7/25/2019, p. 149/194
142/144 termetallic (Mg, Ca, Y, La, Ce) 2 (Sn, Bi, In) having a grain size of less than 1 pm is present with an area fraction of 3% or more in an optional cross section of Zn-AI-Mg alloy layer in an optional sectional structure of the Zn-AI-Mg alloy layer.
ADDITIONAL DECLARATION 4 [00535] The fusion-coated steel sheet according to any of Additional Statements 1 to 3, in which a ternary eutectic structure of Zn-AI-MgZn2 is not present in the coating layer.
ADDITIONAL DECLARATION 5 [00536] The fusion-coated steel sheet according to any of Additional Statements 1 to 4, based on an X-ray diffraction image obtained from the surface of the coating layer, the image being measured by a Cu-Κα ray with an X-ray output at 40 kV and 150 mA, sum of intensity I ((Mg, Ca, Y, La, Ce) 2 (Sn, Bi, In)) = {I (22, 8 ° intensity (cps)) + I (23.3 ° intensity (cps)) + I (24.2 ° intensity (cps))} is 1000 cps or more.
ADDITIONAL DECLARATION 6 [00537] The melt-coated steel sheet according to any of the additional statements 1 to 5, in which the coating layer contains 0.05% to 3% by weight of Ca, based on an image of X-ray diffraction obtained from the surface of the coating layer, in which the image is measured using a CuKa ray, specific intensity I (MgCaSn + MggSns) = {I (22.8 ° intensity (cps)) + I (26.3 ° intensity (cps))} / l (23, 3 intensity (cps)) is less than 0.3 (provided that excludes a case where I (23.3 ° intensity (cps )) is less than 500 cps).
ADDITIONAL DECLARATION 7 [00538] Steel sheet coated with melting according to which
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143/144 wants one of Additional Statements 1 to 6, wherein the coating layer contains 0.05% to 3% by weight of Ca and a Ca-Zn-AI intermetallic compound that has a grain size of 1 pm or more is present with an area fraction of 5% or more in an optional cross section of the Zn-AI-Mg alloy layer in an optional sectional structure of the Zn-AI-Mg alloy layer.
ADDITIONAL DECLARATION 8 [00539] The melt-coated steel sheet according to any of Additional Statements 1 to 7, wherein the coating layer contains 3% to 20% by weight of Sn, 0.05 <% of Sn / % Zn is satisfied, a phase composed of (Mg, Ca, Y, La, Ce) 2 (Sn, Bi, In) that has a grain size of 1 pm or more is present with a fraction of area of 3% or more in an optional cross section of the Zn-AI-Mg alloy layer in an optional sectional structure of the Zn-AI-Mg alloy layer.
ADDITIONAL DECLARATION 9 [00540] The fusion-coated steel sheet according to any of Additional Statements 1 to 8, in which an eutectoid structure composed of a Zn phase and an Al phase and having a lamellar spacing of less than 300 nm is present in an area fraction of 10% or more in an optional cross section of the Zn-AI-Mg alloy layer in an optional sectional structure of the Zn-AI-Mg alloy layer.
ADDITIONAL DECLARATION 10 [00541] The melt-coated steel sheet according to any of Additional Statements 1 to 9, wherein the coating layer also includes an Al-Fe alloy layer, the Al-Fe alloy layer is formed in the steel product and the Zn-AI-Mg alloy layer is formed in the Al-Fe alloy layer.
[00542] The disclosure of Japanese Patent Application No. 2017
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013198 is hereby incorporated by reference in its entirety.
[00543] All documents, patent applications and technical standards described herein are incorporated by reference to the same extent that it is specifically and individually described that individual documents, patent applications and technical standards are incorporated herein by reference.

权利要求:
Claims (14)
[1]
1. Steel product coated with a steel product and a coating layer including a layer of Zn-AI-Mg alloy disposed on a surface of the steel product, where the layer of Zn-AI-Mg alloy has a Zn phase, and the Zn phase includes an Mg-Sn intermetallic compound phase, where the coating layer consists of percentage (%) by weight:
Zn: more than 65.0%,
Al: from more than 5.0% to less than 25.0%,
Mg: from more than 3.0% to less than 12.5%,
Sn: from 0.1% to 20.0%
Bi: from 0% to less than 5.0%,
In: from 0% to less than 2.0%,
Ca: from 0% to 3.00%
Y: from 0% to 0.5%
La: from 0% to less than 0.5%,
Ce: from 0% to less than 0.5%,
Si: from 0% to less than 2.5%,
Cr: from 0% to less than 0.25%
Ti: from 0% to less than 0.25%
Ni: from 0% to less than 0.25%
Co: from 0% to less than 0.25%
V: from 0% to less than 0.25%
Nb: from 0% to less than 0.25%,
Cu: from 0% to less than 0.25%
Mn: from 0% to less than 0.25%
Fe: from 0% to 5.0%,
Sr: from 0% to less than 0.5%,
Sb: from 0% to less than 0.5%,
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[2]
2/5
Pb: from 0% to less than 0.5%,
B: from 0% to less than 0.5% and impurities and characterized by the fact that the coating layer has a chemical composition that meets the following Formulas 1 to 5:
Formula 1: Bi + In <Sn
Formula 2: Y + La + Ce <Ca
Formula 3: Si <Sn
Formula 4: 0 Cr + Ti + Ni + Co + V + Nb + Cu + Mn <0.25
Formula 5: 0 <Sr + Sb + Pb + B <0.5 where, in Formulas 1 to 5, each element symbol represents a content of a corresponding element in terms of percentage (%) by mass.
2. Coated steel product according to claim 1, characterized in that the phase of the intermetallic compound MgSn has an average grain size of less than 1 pm.
[3]
3. Coated steel product according to claim 1 or 2, characterized by the fact that, in a cross section of the Zn-AI-Mg alloy layer, the phase of the Mg-Sn intermetallic compound which has a size of grain less than 1 pm has an area fraction of 10% to 50% in relation to the Zn phase including the Mg-Sn intermetallic compound phase.
[4]
4. Coated steel product according to any one of claims 1 to 3, characterized in that, in a cross section of the Zn-AI-Mg alloy layer, the Zn phase including the phase of the intermetallic compound Mg -Sn is present with an area fraction of 3% or more in relation to the cross section of the Zn-AI-Mg alloy layer.
[5]
5. Coated steel product, according to any
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3/5 of claims 1 to 4, characterized by the fact that, based on an X-ray diffraction image of a coating layer surface, the image is measured using a Cu-raioα ray with an output of X-rays at 40 kV and 150 mA, a specific intensity I (Mg-Sn intermetallic compound phase) = {I (22.8 ° intensity (cps)) + I (23.3 ° intensity (cps)) + I (24.2 ° intensity (cps))} / 3 x I (20 ° background intensity (cps)) is 1.5 or more.
[6]
6. Coated steel product according to any one of claims 1 to 5, characterized in that the coating layer has a Ca content of 0.05% to 3.00% by weight, and the Zn phase contains, like the Mg-Sn intermetallic compound phase, an MgCaSn phase and an MggSns phase, in which, based on an X-ray diffraction image of a coating layer surface, the image is measured using of a Cu-Κα ray with an X-ray output at 40 kV and 150 mA, a specific intensity I (MgCaSn + MggSns) = {I (22.8 ° of intensity (cps)) + I (26.3 ° of intensity (cps))} / l (23.3 ° intensity (cps)) is less than 0.3 and I (23.3 ° intensity (cps)) is 500 cps or more.
[7]
7. Coated steel product according to claim 5, characterized by the fact that the coating layer has an Mg content of more than 4.0% to less than 12.5% by weight, a Ca content of 0.05% to 3.00% by weight and a Si content of 0.01% to 2.5% by weight, in which, based on the X-ray diffraction image of the coating layer surface, the image is measured using a Cu-Κα ray with an X-ray output at 40 kV and 150 mA, a diffraction peak that has a stronger intensity between the diffraction peaks that appear between 23.0 ° and 23.46 ° appear between 23.36 ° and 23.46 °.
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4/5
[8]
Coated steel product according to any one of claims 1 to 7, characterized in that the coating layer has a Ca content of 0.05% to 3.00% by weight and a Si content of 0.01% to 2.5% by weight, in which the Zn-AI-Mg alloy layer has at least one selected from the group consisting of a Ca-AI-Si intermetallic compound phase that has an average size grain of 1 pm or more and a phase of Mg-AI-Si intermetallic compound which has an average grain size of 1 pm or more.
[9]
9. Coated steel product according to any one of claims 1 to 8, characterized by the fact that the coating layer has a Ca content of 0.05% to 3.00% by weight, in which, in a cross section of the ZnAI-Mg alloy layer, a phase of Ca-Zn-AI intermetallic compound that has a grain size of 1 pm or more is present with an area fraction of 5% or more relative to the cross section of the Zn-AI-Mg alloy layer.
[10]
10. Coated steel product according to any one of claims 1 to 9, characterized by the fact that the coating layer has a Sn content of 3.00% to 20.00% by weight and the following Formula is satisfied :
0.05 <Sn / Zn, where each Sn and Zn represents the content of the corresponding element, in which, in a cross section of the ZnAI-Mg alloy layer, a phase of Mg-Sn intermetallic compound that has a grain size of 1 pm or more is present with an area fraction of 3% or more in relation to the cross section of the Zn-AI-Mg alloy layer.
[11]
11. Coated steel product according to any one of claims 1 to 10, characterized by the fact that, in one
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5/5 cross section of the Zn-AI-Mg alloy layer, a eutectoid structure composed of a Zn phase and an Al phase, and which has a lamellar spacing of less than 300 nm, is present with a fraction of area of 10% or more in relation to the cross section of the Zn-AI-Mg alloy layer.
[12]
12. Coated steel product according to any of claims 1 to 11, characterized by the fact that a ternary eutectic structure of Zn-AI-MgZn ₂ has an area fraction of 0% to 5% in a cross section of the alloy layer of Zn-AI-Mg.
[13]
13. Coated steel product according to any one of claims 1 to 9, characterized in that the Sn content of the coating layer is from 0.10% to less than 3.00%.
[14]
Coated steel product according to any one of claims 1 to 13, characterized in that the coating layer has an Al-Fe alloy layer between the steel product and the Zn-AI alloy layer -Mg.

类似技术:

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公开号 | 公开日 | 专利标题

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BR112019015377A2|2020-03-10|COATED STEEL PRODUCT

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公开号 | 公开日

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TWI658171B|2019-05-01|

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MX2019008678A|2019-11-11|

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KR102289682B1|2021-08-13|

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JPWO2018139619A1|2019-01-31|

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EP3575433A4|2020-09-23|

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JP6428974B1|2018-11-28|

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AU2018211810A1|2019-08-22|

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TW201831708A|2018-09-01|

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US20190390303A1|2019-12-26|

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WO2018139619A1|2018-08-02|

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AU2018211810B2|2020-09-10|

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KR20190099064A|2019-08-23|

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CN110268087B|2021-09-03|

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NZ756405A|2021-05-28|

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PH12019501701A1|2020-06-08|

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SG11201906850RA|2019-08-27|

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EP3575433A1|2019-12-04|

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法律状态:
2021-10-13| B350| Update of information on the portal [chapter 15.35 patent gazette]|

优先权:

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申请号 | 申请日 | 专利标题

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JP2017-013198|2017-01-27|

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JP2017013198|2017-01-27|

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PCT/JP2018/002595|WO2018139619A1|2017-01-27|2018-01-26|Plated steel|

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