• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a method for manufacturing a plated steel sheet provided as a building material, high strength, drawing processability and high corrosion resistance, steel sheet for hot air heating and hot water supply equipment, automotive steel sheet, etc., comprising a steel slab containing C: 0.5wt% or less After heating to a temperature range of Ac 3 transformation point or more, and performing hot-rolling and hot-rolling rolling, high pressure water with a discharge pressure of 300 kg / cm 2 or more is sprayed on the surface of the steel sheet at least once to remove the iron oxide layer. At the same time, after winding the steel sheet with the steel sheet temperature at the end of the final hot finishing rolling mill at 500 to 800 ° C., after reducing 50 to 90% of the iron oxide layer on the surface of the steel sheet at a steel sheet temperature of 750 to 900 ° C. in the annealing furnace. It is a method which can manufacture the plated steel plate which is excellent in workability and plating adhesiveness even if it abbreviate | omits cold rolling and acid washing by performing plating, It is characterized by the above-mentioned.
    公开号:KR19990043945A
    申请号:KR1019970065789
    申请日:1997-11-29
    公开日:1999-06-15
    发明作者:마코토 이소베；가즈히로 세토；치아키 가토
    申请人:에모토 간지；가와사키 세이테츠 가부시키가이샤；
    IPC主号:
    专利说明:

    Manufacturing Method of Plated Steel Sheet
    The present invention relates to a method for producing a plated steel sheet provided in building materials, high-temperature heating and heating equipment, steel plates for automobiles, and the like, which require high strength, drawing processing and high corrosion resistance.
    A plated steel sheet is normally manufactured by the following process. In other words, the iron oxide layer (hereinafter referred to as scale) on the surface of the steel sheet generated in the hot rolling process of hot rolling the slab to form a steel sheet is removed from the acid cleaning equipment. Subsequently, depending on the required quality, after performing cold rolling and recrystallization annealing, a plated steel sheet is obtained by plating with a continuous hot dip plating apparatus, an electroplating apparatus, or the like. In this case, if the scale generated on the surface of the steel sheet is not removed during hot rolling, the scale prevents the plating and becomes the starting point of the peeling of the plating layer, which deteriorates the adhesion of the plating. In addition, by recrystallization annealing after cold rolling, a plated steel sheet excellent in workability such as elongation and drawing characteristics can be ensured.
    Various methods have been tried to improve the conventional manufacturing method of the coated steel sheet. For example, Japanese Patent Laid-Open No. Hei 6-145937 and Japanese Laid-Open Hei 6-279967 disclose a technique of omitting an acid washing step and a cold rolling step mainly to reduce costs. That is, after performing a reduction process in a reducing atmosphere gas without removing the scale of the hot-rolled steel sheet surface, performing hot dip galvanization is proposed. Further, Japanese Patent Laid-Open Nos. 9-143662 and 9-217160 disclose a method of improving scale plating adhesion by putting a clock on the scale of a steel sheet surface by a tension leveler or the like before performing a reduction treatment. . However, the above publications do not describe any deterioration of workability caused by the omission of cold rolling. In addition, Japanese Patent Laid-Open No. 6-145937 has no description regarding the adhesion of plating. Although Japanese Unexamined Patent Publication No. 6-279967 improves the adhesion of plating by using a hot rolled steel sheet having a thin scale of 1.1 to 4.6 mu m, there is no disclosure regarding a specific method for obtaining a thin scale. In addition, Japanese Patent Application Laid-open No. Hei 9-143662 and Japanese Laid-Open Patent Application No. Hei 9-217160 put the scale clock before reduction, so that the adhesion between the steel sheet and the scale is reduced, the scale peels during the reduction treatment, and the scale falls into the processing furnace, There exists a possibility of being stuck and a flaw in a steel plate.
    On the other hand, in order to increase the strength of the plated steel sheet by the conventional method, the following problems arise when using a kind of steel in which a dispersing component such as Si or Mn exists in steel. In other words, this component was oxidized during annealing before plating and condensed on the surface of the steel sheet, which hindered the reaction between the steel sheet and the molten metal during the plating treatment, thereby preventing plating.
    An object of the present invention is to propose a method for producing a plated steel sheet at low cost without impairing high strength, processability and plating adhesion even if acid cleaning and cold rolling are omitted in the manufacturing process of the plated steel sheet.
    The present inventors earnestly examined the temperature and processing conditions of hot rolling, the descaling conditions after rough rolling, the thickness of the scale of a hot rolled steel sheet, and the material of the steel plate after annealing. Further, the steel sheet on which the scale was formed was subjected to reduction treatment under various conditions, plating was performed, and the plating characteristics thereof were examined. As a result, by incorporating work deformation into a hot rolled steel sheet, it is possible to prevent deterioration of workability even if the cold rolling is omitted, or to reduce the scale generated on the hot rolled steel sheet surface to secure the adhesion of plating without removing the scale. I figured out.
    That is, according to the present invention, after heating the steel slab of C: 0.5wt% or less in a temperature range of Ac 3 transformation point or more, and performing hot rough rolling and hot finishing rolling, high pressure water having a discharge pressure of 300 kg / cm 2 or more Is sprayed on the surface of the steel sheet at least once to remove the scale, and wound the steel sheet with the final hot finish rolling mill exit temperature at 500 ° C or higher and 800 ° C or lower, and then in an annealing furnace at an atmosphere of 750 ° C or higher and 900 ° C or lower. 50% or more and 98% or less of the scale of the surface of the steel sheet is reduced, followed by plating.
    Other configurations of the present invention will become apparent from the following detailed description, together with modifications thereof.
    Next, the procedure of this invention is demonstrated concretely.
    In the present invention, a steel slab containing C: 0.5 wt% or less is used as a raw material for coated steel sheet. Further, in order to obtain a high-strength plated steel sheet, steel slabs of C: 0.02wt% or more and 0.5wt% or less, Si: 2wt% or less and Mn: 3wt% or less are used. In addition, in order to obtain a plated steel sheet excellent in workability, less than C: 0.02wt%, Si: 2wt% or less, Mn: 3wt% or less, Ti: 0.2wt% or less, Nb: 0.2wt% or less and N: 0.01wt% or less And using a steel slab satisfying Equation 1 below.
    [C] / 12 + [N] / 14≤ [Ti] / 48 + [Nb] / 93
    The reason for limitation of each component is demonstrated below.
    C: 0.5 wt% or less, 0.02 wt% or more and 0.5 wt% or less and less than 0.02 wt%
    C is an invasive solid solution element and is effective for increasing the strength of the steel sheet, while decreasing workability represented by elongation and r value. Therefore, in the present invention, C is suppressed to 0.5wt% or less in the steelmaking step.
    In addition, in this invention, in order to reduce the cost of another alloy component, C is divided into the following two ranges.
    First, in order to obtain a high-strength plated steel sheet, slabs having a C: 0.02wt% or more and 0.5wt% or less are used. Here, the lower limit of C is made 0.02 wt% or more due to the following reasons.
    It is because it becomes possible to precipitate cementite by making C or more into 0.02 wt%, and to obtain a high strength steel plate easily and at low cost. However, when C exceeds 0.5wt%, the deformation resistance at high temperature becomes high and final finishing rolling below 800 ° C for obtaining a thin scale becomes difficult.
    Next, slabs of less than C: 0.02 wt% are used to obtain a plated steel sheet excellent in workability. The lower limit of C is less than 0.02 wt% here for the following reasons.
    In order to obtain a steel sheet excellent in workability, it is necessary to remove free C in steel.
    Thereby, a structure with good workability can be obtained with a ferrite single phase. In addition, by depositing and fixing a small amount of C, workability deterioration caused by aging or the like can be avoided. In addition, although Ti and Nb are added in a required amount as will be described later, the amount is made less than C: 0.02 wt% due to the cost increase and avoidance of excessive precipitation. In this case, although a minimum is not specifically limited, In order to suppress steelmaking cost, it is preferable to set it as 0.0005 wt% or more.
    The following components can be added according to the use of a steel plate.
    Si: 2 wt% or less, Mn: 3 wt% or less
    Si and Mn are components that increase the strength of the steel sheet without relatively hindering workability and may add 2 wt% and 3 wt% as an upper limit, respectively. In addition, when the upper limit is exceeded, cracking is likely to occur at the steel sheet edge portion during hot working, and scale is formed in a deformed shape, and a clean steel sheet surface is not obtained. In addition, although the minimum of Si and Mn is not specifically limited, It adjusts according to the intensity | strength required. However, in order to avoid an increase of steel cost, it is preferable to set it as 0.001 wt% and 0.01 wt%, respectively.
    N: 0.01 wt% or less
    N is controlled to obtain a plated steel sheet excellent in workability. The amount is limited to 0.01 wt% or less. N and C are similarly effective in increasing the strength of the steel sheet and are invasive solid solution elements, but on the other hand, workability represented by elongation and r value is reduced. Therefore, in the present invention, N is suppressed to 0.01wt% or less in the steelmaking step.
    Ti: 0.2wt% or less, Nb: 0.2wt% or less
    In order to obtain a plated steel sheet excellent in workability, Ti and Nb are added. In order to make harmless the bad effect of trace amounts of C and N in steel on the workability, Ti and Nb are added to react and precipitate C and N, thereby securing excellent workability. Specifically, it is important to add Ti: 0.2wt% or less and Nb: 0.2wt% or less, based on the formula (1), to the contents of C and N.
    (Equation 1)
    [C] / 12 + [N] / 14≤ [Ti] / 48 + [Nb] / 93
    This is because Ti is more reactive than Nb and selectively consumed for precipitation of N and C. Since Ti is easily oxidized and consumed for oxygen in steel, the effect of addition is not shown at less than 0.01 wt%. On the other hand, even if it exceeds 0.2 wt%, the effect will be excessive and cost will increase.
    In addition, since Nb has a lower reactivity with elements other than C than Ti, it exhibits an effect from the addition of a small amount. However, when Nb is less than 0.001 wt%, the number of atoms present as atoms is too small compared to the amount of C and N, and thus the effect is not shown. On the other hand, the addition of more than 0.2wt% is too effective and leads to an increase in cost.
    In addition, Ti and Nb can be secured in a sufficient amount to precipitate C and N by adding in a range satisfying Equation 1 according to the amount of C and N.
    Next, manufacturing conditions will be described.
    Slab heating temperature: above Ac 3 transformation point
    In the hot rolling process, the steel slab adjusted to the above components before the rough rolling is heated to the Ac 3 transformation point or more. Specifically, the slab is heated to about 1200 ° C. to decrease the deformation resistance of the steel sheet in subsequent rough rolling. Moreover, you may provide the slab cast by continuous casting etc. as it is to a rough rolling process before cooling, without heating a slab again.
    Hot rolled
    After the slab is heated to a predetermined temperature, rough rolling is performed under the rolling conditions usually performed in a rough rolling mill consisting of a plurality of stands.
    Hot Finish Rolling
    The rough-rolled steel sheet is subjected to finish rolling under the rolling conditions usually carried out in a finish mill consisting of a plurality of stands. In this case, after manufacturing the steel plate temperature of the final hot finishing rolling mill exit side at 500 degreeC or more and 800 degrees C or less, a steel plate is wound up. The temperature of the steel sheet on the exit side of the final hot finish rolling mill is 500 ° C. or higher because the steel sheet becomes excessively hard when it is 500 ° C. or lower, and rolling becomes impossible. In addition, setting it as 800 degrees C or less is for suppressing growth of a scale immediately after hot rolling, and can specifically suppress the thickness of a scale in a hot rolled steel sheet about 4 micrometers or less.
    In order to obtain a high-strength plated steel sheet, when using a steel slab of C: 0.02wt% or more, 0.5wt% or less, Si: 2wt% or less and Mn: 3wt% or less, while applying tension to the front and rear ends of hot finishing rolling It is important to perform hot finish rolling. The reason for giving tension is as follows. In this case, since the steel sheet which has relatively high C content is finish-rolled at low temperature, the deformation resistance of the steel sheet is large and the pressing force is excessive. As a result, rolling becomes uneven and shape defects, such as drawing, are caused. Therefore, by performing rolling while applying a uniform tension to the steel sheet during finish rolling, it is possible to eliminate the shape defect of the steel sheet described above. In the method of applying tension to the front and rear ends of rolling, the steel sheet during finish rolling can be uniformly tensioned by connecting the rear end of the steel sheet or slab to the front end of the next steel sheet or slab in advance by welding or pressing and performing continuous rolling. It is.
    In addition, in order to obtain a plated steel sheet excellent in workability, it is less than C: 0.02 wt%, Si: 2 wt% or less, Mn: 3 wt% or less, Ti: 0.2 wt% or less, Nb: 0.2 wt% or less, and N: 0.01 wt% or less. In the case of using a steel slab satisfying Equation 1, hot finish rolling with a reduction ratio of 60% or more is performed in a temperature range below the Ar 3 transformation point, and the exit temperature of the final hot finish rolling mill is 500 ° C. or higher and 800 ° C. or lower. The rolled steel sheet is wound up. In this case, by rolling the reduction ratio to 60% or more at a temperature below the Ar 3 transformation point, it is possible to incorporate work strain in the hot rolled steel sheet after cooling. The rolling reduction at 60% or more at a temperature below the Ar 3 transformation point is for obtaining a steel sheet having good workability by recrystallization in a ferrite single phase region. That is, in the recrystallization at the time of reduction in a reduction furnace, the structure favorable for provision of high workability arises. Therefore, workability can be ensured without performing cold rolling.
    Descaling by high pressure water: more than 300kgf / ㎠ discharge pressure
    Normally, water having a discharge pressure of 150 kgf / cm 2 or less is sprayed on the steel plate surface during hot rough rolling and hot finishing rolling. In the present invention, the scale generated on the surface of the steel sheet is removed by spraying the high-pressure water at least once and roughly 300 kgf / cm 2 or more from rough rolling to finish rolling. In this case, it is preferable to perform descaling with high pressure water before finishing rolling after finishing rough rolling. And it is important to spray high pressure water over the full width of the steel plate surface. The high-pressure water having a discharge pressure of 300 kgf / cm 2 or more is used here to remove the scale efficiently and almost completely without damaging the surface of the steel sheet produced and grown until rough rolling. If the scale is less than 300 kgf / cm 2, the removal of the scale is not complete, and as a result, the scale on the hot rolled steel sheet after finishing rolling and winding becomes thick and uneven. It is possible to clean the surface of the hot rolled steel sheet by descaling with high pressure water and reducing the thickness of the oxide scale. In addition, a clean plated steel sheet having good plating adhesion can be produced by performing a reduction treatment in a continuous hot-dip heating furnace without performing descaling by acid washing again.
    On the other hand, when plating is performed using a hot rolled steel sheet having a thick and poor surface shape, which is manufactured by a conventional method that does not descale by high pressure water, if descaling is not performed by acid cleaning, It is difficult to manufacture a clean plated steel sheet having good plating adhesion. In addition, in order to effectively descale by the high pressure water, it is preferable to keep the gap between the nozzle and the steel sheet at 80 mm to 250 mm. Moreover, it is preferable that the quantity is 1 cm <3> or more per 1 cm <2> of areas.
    Annealing and Reduction
    After the hot rolled steel sheet is rolled off, in the case of performing hot dip plating, the hot rolled steel sheet is reduced simultaneously with recrystallization annealing in an annealing furnace of a continuous hot dip plating apparatus, and then plating is performed.
    That is, in the continuous hot-dip plating apparatus, the scale is reduced in the annealing furnace and recrystallization is generated in the steel sheet.
    In order to perform both reactions here quickly, it is necessary to reduce steel plate temperature at 750 degreeC or more and 900 degrees C or less. The reason for this is that the reaction rate is lowered below 750 ° C. On the other hand, when it exceeds 900 ° C, the structure becomes coarse or randomized so that a structure with favorable processability cannot be obtained.
    In addition, in order to obtain a plated steel sheet excellent in workability, it is less than C: 0.02wt%, Si: 2wt% or less, Mn: 3wt% or less, Ti: 0.2wt% or less, Nb: 0.2wt% or less and N: 0.01wt% or less In the case of using the steel slab satisfying the above formula (1), it is necessary to perform plating after reducing from 900 to 750 ° C. or lower or lower temperature of the Acs transformation point in the annealing furnace.
    The upper limit of the reduction temperature in the annealing furnace is set to 900 ° C or lower than the temperature of the Acs transformation point for the following reasons.
    When obtaining the steel plate excellent in workability, when a reduction temperature is 900 degreeC or more, a steel plate will soften and a board | plate will become unstable. In addition, the crystal grains are easily coarse, and once the crystal grains are coarse, irregularities are formed on the surface of the steel sheet during processing. In addition, in order to improve workability, it is necessary to recrystallize in a ferrite single phase region. Therefore, annealing needs to be performed below Acs transformation point. For the above reasons, the upper limit of the reduction temperature is set to 900 ° C or lower of the Acs transformation point.
    In addition, it is necessary to reduce the scale at 50% or more and 98% or less. This is because when the reduction rate is less than 50%, there is a large amount of scale remaining, and when the impact or processing is performed, peeling may be issued to withstand practical use. On the other hand, when 98% is exceeded, absorption of hydrogen atoms is started, and when this is high, hydrogen is not discharged from the steel after plating and vaporizes at the plating interface to progress to local plating peeling. In addition, especially in the case of containing Si or Mn at a high concentration, if 98% reduction occurs, surface thickening occurs due to oxidation of Si or Mn, so that wettability in the subsequent plating process may be disturbed to cause defects that cannot be plated. do.
    The atmosphere is typically reduced to use the N 2 containing gas of more than 3% H 2, but it is preferable that the H 2 concentration There performed efficiently reduced to less than 7%.
    Plated
    The steel sheet on which the predetermined reduction and recrystallization annealing has been completed is, for example, hot dip plating, cooled to a plating bath temperature and then introduced into the plating bath to perform plating. In addition to Zn and Fe, zinc-based plating baths are used for the purpose of improving various performances, and include Al, Mg, Mn, Ni, Co, Cr, Si, Pb, Sb, Bi, Sn, etc. alone or in combination. It is possible.
    Finally, the steel plate plated by immersion is adjusted to the required lamination amount between 20 and 250 g / m 2 by gas wiping, and then cooled by air cooling, air cooling, or water cooling, and then leveler or temper rolling as necessary. To become a product. In addition, in order to improve corrosion resistance and the like, after cooling or temper rolling, it is also possible to perform a clomate treatment, a phosphate treatment, or the like, and coating is also effective. Similarly, it is also possible to perform lubrication treatment as a post treatment.
    On the other hand, in applications in which steel sheets are assembled and used by spot resistance welding or the like, it is effective to perform plating by heating in a molten Zn bath containing 0.1 to 0.2 wt% of Al and adjusting the lamination amount, followed by heat alloying. If the lamination amount here is less than 20 g / m 2 and the corrosion resistance becomes insufficient and 80 g / m 2 is exceeded, plating will be easily peeled off during bending and drawing processing, and therefore it is preferable to set it in the range of 20 to 80 g / m 2. Similarly, the Fe content in the plating is set to 7 to 12 wt%. If the content is less than 7wt%, the unalloyed pure Zn layer remains on the surface of the plating, which hinders spot resistance weldability, and after coating, the pure Zn layer is easily eluted from scratches. It is because peeling of plating becomes remarkable at the time of processing.
    As mentioned above, although hot-dip galvanized steel sheet was mainly demonstrated, this invention is not limited to a hot-dip galvanized steel sheet, It is similarly applicable to other hot dip galvanized steel plate or an electroplated steel sheet. For example, a plated steel sheet such as 55% Al-Zn plating, Al plating, Pb plating, Sn plating or Zn-Ni plating is suitable. In any case, plating may be performed after the reduction treatment of 50% or more and 98% or less, and a steel sheet having excellent plating characteristics can be obtained without being bound by the plating type. In the hot dip galvanizing line, it is usual to arrange the plating bath continuously in the annealing furnace, so it is particularly suitable for the present invention.
    (Example)
    The highlight slab shown in Table 1 was heated to 1200 degreeC, and normal rough rolling was performed. Subsequently, after welding and connecting the rear end of the steel plate and the front end of the next steel plate, descaling and continuous hot rolling were performed under the conditions as shown in Tables 2A and 2B to obtain a 0.8 mm thick hot rolled steel sheet. In finish rolling, lubrication with mineral oil was performed. As a conventional example, after hot rolling, acid washing and cold rolling were performed under the conditions shown in Table 3 to produce a cold rolled steel sheet.
    Subsequently, this hot rolled sheet steel and the cold rolled sheet steel were cut into the test piece of 60x200 mm, and it wash | cleaned with acetone. Subsequently, reduction treatment and recrystallization annealing were carried out in a vertical molten metal plating simulator, followed by zinc plating. Table 2a and Table 2b show the descaling, hot rolling and annealing conditions and the scale thickness of the hot rolled steel sheet. Table 3 shows each condition of hot rolling, cold rolling, and annealing by the conventional method. Table 4a and 4b show the plating conditions, respectively. About the plated steel plate obtained in this way, the reduction rate of the scale was measured, and the mechanical property and plating adhesiveness were evaluated. The reduction rate and mechanical properties of the scale are shown in Tables 2a, 2b and 3, and the evaluation results of the plating adhesion are shown in Tables 4a and 4b, respectively. Here, the reduction rate of the scale was previously determined separately from the scale which was subjected to acid washing to remove and removed.
    In addition, plating adhesiveness was evaluated by the ball impact test and the test which bends out 180 degree | times. That is, in the ball impact test, a core having a half-spherical convex surface having a diameter of 1/2 inch touches the inner side of the test surface, and a 2 kg weight is dropped from a height of 70 cm with a hemispherical concave base plate on the test surface side. The hardened and protruding test surface was attached with a cellophane adhesive tape, then peeled off, and the surface of the plated steel sheet was observed. In addition, for the test to bend 180 degrees outward, the vinyl adhesive tape is applied to the test surface in advance, and 0.8 mm steel sheet is put into the spacer, and the test surface is bent 180 degrees to the outside with a hydraulic press, and then flattened again. The tape was removed and the surface of the plated steel sheet was observed.
    As is clear from Tables 1 to 4b, the plated steel sheets obtained according to the present invention all have target characteristics, and are excellent in plating adhesion. Sample Nos. 1 and 3 of the steel sheets produced from the slabs of steel types A and B according to the manufacturing conditions of the present invention have TS of more than 400 MPa and are excellent in high strength and plating adhesion. Samples Nos. 9, 12, 13, and 16 of steel sheets made of slabs of steel types D, E, F, and G according to the manufacturing conditions of the present invention have an r value of more than 1.3, and are excellent in workability and plating adhesion.
    On the other hand, the sample No. which is a comparative example in which a component composition and manufacturing conditions are out of the range of this invention. 2,4,5,6,7,8,10,11,14,15 and Nos. 17 and 18 of the prior art show that a satisfactory steel sheet is not obtained or the plating adhesion is poor even if obtained.
    According to the present invention, a plated steel sheet excellent in high strength, drawing workability, high corrosion resistance and plating adhesion can be obtained by omitting the step of removing the scale. In addition, since acid washing and cold rolling can be skipped in the manufacturing process of a plated steel sheet, a plated steel sheet can be provided at low cost.
    (wt%) River typeCSiMnPSAlNTiNb* X valueRemarks A0.250.010.520.010.010.04----Example of fit B0.080.101.80.080.010.05----Example of fit C1.20.010.050.060.080.02----Comparative example D0.00350.960.620.1210.0050.0440.0010.0480.0030.000669Example of fit E0.00250.141.710.1190.0060.0490.0020.0390.0070.000525Example of fit F0.00210.020.530.0610.0060.0430.0020.0410.0080.000622Example of fit G0.00390.261.230.1480.0070.0410.0010.0520.0050.000741Example of fit
    * X = [Ti] / 48 + [Nb] / 93-[C] / 12-[N] / 14
    No.River typeDescaling Water Pressure (㎏ / ㎠)* Rolling divisionHot rolled finish exit temperature (℃)Pressure drop below Ar 3 (%)Winding temperature (℃)Scale thickness (㎛)Reduction Annealing** Scale reduction rate (%)TS (MPa)***kidney(%)*** r valueRemarks Hydrogen(%)Temperature (℃)Time (S) OneA450continuity750-6103.0208204071420320.6Example of fit 2A350Exclusive760-6103.0Drawing occurs at the back of steel plateComparative example 3B450continuity750-4503.5208204071500280.7Example of fit 4B100continuity750-4505.5208204045500280.7Comparative example 5B350continuity760-6203.8207304039530240.6Comparative example 6B350continuity900-6008.8208204028570250.8Comparative example 7B350continuity450-3501.3Unable to roll up to 0.8 mm sheet thicknessComparative example 8C350continuity750-6004.2Cracks at the edge of steel sheetComparative example 9D450continuity750756102.9208204071500301.4Example of fit 10D250continuity820306105.5208206045480331.2Comparative example
    No.River typeDescaling Water Pressure (㎏ / ㎠)* Rolling divisionHot rolled finish exit temperature (℃)Pressure drop below Ar 3 (%)Winding temperature (℃)Scale thickness (㎛)Reduction Annealing** Scale reduction rate (%)TS (MPa)***kidney(%)*** r valueRemarks Hydrogen(%)Temperature (℃)Time (S) 11D350continuity760756203.1207306039540271.0Comparative example 12E350continuity760756203.6208204068460411.8Example of fit 13F350continuity760756203.6208204068370411.7Example of fit 14F150continuity780656006.2208204042360421.6Comparative example 15F350continuity93006809.5208204027350431.0Comparative example 16G350continuity750755902.7208204068510311.4Example of fit
    * Pressure study powder: Continuously, the steel plate and the steel plate were connected by welding, and continuous hot finishing rolling was performed to give tension to the steel plate.
    Individually hot-rolls one slab and does not give tension to a steel plate.
    ** Scale reduction rate was calculated | required separately as the ratio which calculated | required the amount of scale removed by acid washing previously from the weight reduced by the annealing reduction under the same conditions as plating.
    *** Steel sheet material was obtained by experiment after plating.
    No.Type of riverHot rolled finish temperature (℃)Winding temperature (℃)Removal of scaleCold rolling rate (%)Reduction AnnealingTS (MPa)*kidney(%)* r value (%)Remarks Hydrogen(%)Temperature (℃)Time (S) 17B900600Pickling652082040570250.7Conventional example 18G930680Pickling752082040500311.6Conventional example
    * Steel sheet material was obtained by experiment after plating.
    No.Plating bathPlating time (S)Stacking amount (g / ㎡)Plating appearance* Ball impact result* Experimental results of bending outside 180 °** Comprehensive evaluation of steel sheetRemarks FurtheranceTemperature (℃) OneZn-5% Al460360GoodOneOne◎Example of fit 3Zn-5% Al4603120GoodOneOne◎Example of fit 4Zn-5% Al4603120Good33△Comparative example 5Zn-0.2% Al4603120Good33△Comparative example 6Zn-0.2% Al4603120Good33△Comparative example 9Zn-0.2% Al460360GoodOneOne◎Example of fit 10Zn-0.2% Al460360Good32△Comparative example 11Zn-0.2% Al4603220Good33△Comparative example 12Zn-0.2% Al4603120GoodOneOne◎Example of fit
    No.Plating bathPlating time (S)Stacking amount (g / ㎡)Plating appearance* Ball impact result* Experimental results of bending outside 180 °** Comprehensive evaluation of steel sheetRemarks FurtheranceTemperature (℃) 13Zn-5% Al4603120GoodOneOne◎Example of fit 14Zn-5% Al4603120Good33△Comparative example 15Zn-5% Al460390Good43△Comparative example 16Zn-5% Al460390GoodOneOne◎Example of fit 17Zn-0.2% Al460390Not plated33×Conventional example 18Zn-0.2% Al460360Not plated2One×Conventional example
    * The evaluation of plating adhesion is performed both in the ball impact test and in the experiments that bend outside 180 °.
    (Right) 1: After the test, the tape is peeled off further and there is no change in the plated surface.
    2: Small fluff on plating test
    3: Small Peeling Occurred in Plating Experiment
    (Heat) 4: Most of plating part peeled off
    ** Comprehensive evaluation of steel sheet
    (Right) ◎ Good plating and material TS> 400MPa or r> 1.3
    Insufficient plating adhesion or material does not satisfy any of TS> 400MPa or r> 1.3
    (Heat) X no plating
    权利要求:
    Claims (7)
    [1" claim-type="Currently amended] C: 0.5 wt% or less of steel slab is heated to a temperature range of Ac 3 transformation point or more, and then hot rough rolling and hot finishing rolling are performed, and high pressure water having a discharge pressure of 300 kg / cm 2 or more is applied to the surface of the steel sheet once. The above steel sheet was sprayed to remove the iron oxide layer and the steel sheet temperature at the exit of the final hot finish rolling mill was 500 ° C. or higher and 800 ° C. or lower, and the steel sheet was wound. Then, the steel sheet surface was subjected to the steel sheet temperature of 750 ° C. or higher and 900 ° C. or lower in the annealing furnace. 50% or more and 98% or less of the iron oxide layer is reduced, followed by plating.
    [2" claim-type="Currently amended] The method of claim 1,
    A method of producing a coated steel sheet, characterized in that after the completion of hot rough rolling, high-pressure water having a discharge pressure of 300 kgf / cm 2 or more is sprayed at least once on the full width of the steel sheet surface before hot finishing rolling.
    [3" claim-type="Currently amended] The method according to claim 1 or 2,
    Plating characterized in that hot finish rolling is performed using a steel slab of C: 0.02 wt% or more, 0.5 wt% or less, Si: 2 wt% or less, and Mn: 3 wt% or less, while applying tension to the front and rear ends of the hot finish rolling. Method of manufacturing steel sheet.
    [4" claim-type="Currently amended] The method according to claim 1 or 2,
    A steel slab having less than C: 0.02wt%, Si: 2wt% or less, Mn: 3wt% or less, Ti: 0.2wt% or less, Nb: 0.2wt% or less and N: 0.01wt% or less and satisfying the following formula (1) In the temperature range below the Ar 3 transformation point, after performing hot finish rolling with a reduction ratio of 60% or more and winding the manufactured steel sheet, the steel sheet is wound at 750 ° C. or higher and 900 ° C. or lower in the Acs transformation point. The method of manufacturing a coated steel sheet, characterized in that the plating is carried out after the reduction in.
    (Equation 1)
    [C] / 12 + [N] / 14≤ [Ti] / 48 + [Nb] / 93
    [5" claim-type="Currently amended] The method of claim 1,
    Method for producing a plated steel sheet, characterized in that the plating is hot-dip plating.
    [6" claim-type="Currently amended] The method of claim 5,
    Hot-dip galvanizing is a method for producing a coated steel sheet, characterized in that.
    [7" claim-type="Currently amended] The method of claim 6,
    An alloying treatment is performed following hot dip galvanizing.
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    同族专利:
    公开号 | 公开日
    DE69710598T2|2002-08-14|
    US6068887A|2000-05-30|
    CA2222814C|2001-04-03|
    EP0931847A1|1999-07-28|
    KR100274301B1|2000-12-15|
    CA2222814A1|1999-05-28|
    CN1218725A|1999-06-09|
    DE69710598D1|2002-03-28|
    CN1131742C|2003-12-24|
    EP0931847B1|2002-02-20|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1997-11-26|Priority to US08/978,641
    1997-11-28|Priority to CA 2222814
    1997-11-28|Priority to EP19970120977
    1997-11-29|Application filed by 에모토 간지, 가와사키 세이테츠 가부시키가이샤
    1997-11-29|Priority to KR1019970065789A
    1997-11-29|Priority to CN 97120802
    1999-06-15|Publication of KR19990043945A
    2000-12-15|Application granted
    2000-12-15|Publication of KR100274301B1
    优先权:
    申请号 | 申请日 | 专利标题
    US08/978,641|US6068887A|1997-11-26|1997-11-26|Process for producing plated steel sheet|
    CA 2222814|CA2222814C|1997-11-26|1997-11-28|Process for producing plated steel sheet|
    EP19970120977|EP0931847B1|1997-11-26|1997-11-28|Process for producing plated steel sheet|
    KR1019970065789A|KR100274301B1|1997-11-26|1997-11-29|Process for producing plated steel sheet|
    CN 97120802|CN1131742C|1997-11-26|1997-11-29|Method for producing plating steel plate|
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