• 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:
    This process of manufacturing a spheroidal graphite cast iron tubular element by centrifugation comprises the following steps: - A rotary mold (16) is supplied that has a shaped surface (28) of the tubular element, the shaped surface being devoid of insulation temporary thermal, - a casting container (10) containing liquid cast iron is supplied, - the inoculant is deposited on the form surface (28), - a compound containing at least one element that reduces the surface tension of the liquid iron, - the liquid iron is poured into the mold on the surface devoid of temporary thermal insulator or temporary refractory material and provided with inoculant, producing the inoculation of the iron then during contact with the inoculant placed on the form surface, - the liquid cast iron poured into the mold solidifies and the tubular element is obtained ar in roughing. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2804651A2
    申请号:ES202030845
    申请日:2020-08-07
    公开日:2021-02-08
    发明作者:Fabien Bruneseaux；Jacques Bourdie
    申请人:Saint Gobain PAM SA；
    IPC主号:
    专利说明:

    [0001] Manufacturing process of a tubular element
    [0002] Field of the invention
    [0003] The present invention relates to a process for manufacturing a spheroidal graphite cast iron tubular element by centrifugation, in particular a process of the "Delavaud" type, comprising the following steps:
    [0004] A) - a rotary mold is supplied having a shaped surface of the tubular element, the shaped surface being devoid of temporary thermal insulator or temporary refractory material,
    [0005] B) - a casting container containing liquid cast iron is supplied,
    [0006] C) - the inoculant is deposited on the form surface,
    [0007] D) - the liquid cast iron is poured into the mold in the form of a jet of liquid cast deposited along the rotary mold on the surface devoid of temporary heat insulator or temporary refractory material and provided with inoculant, producing the inoculation of the casting when coming into contact with the inoculant arranged on the form surface,
    [0008] E) - the liquid cast iron poured into the mold solidifies and the rough tubular element is obtained. Background
    [0009] Processes for the manufacture of tubes by casting liquid iron in a rotary mold are known. Such a process is known as the "Delavaud casting process".
    [0010] According to this Delavaud procedure, the surface of the mold is devoid of temporary heat insulator or temporary refractory material such as that used during another casting procedure called "Wetspray".
    [0011] The spheroidal graphite cast iron tubes (GS cast iron) obtained by the Delavaud casting process present, after being removed from the mold, pits or protrusions on their outer edge.
    [0012] These pitting are bad for the tube.
    [0013] This pitting phenomenon occurs in particular when the solidification rate of the cast iron is fast, as is the case with the Delavaud manufacturing process.
    [0014] The aim of the invention is therefore to increase the surface quality of spheroidal graphite cast iron tubes in order to limit waste.
    [0015] Description of the invention
    [0016] It has been found that by depositing sulfur on the form surface before pouring the liquid cast iron into the mold, this pitting phenomenon can be significantly reduced in the tubes obtained by the Delavaud process.
    [0017] Therefore, the object of the invention is a procedure such as that indicated above, characterized in that:
    [0018] in step D), while the liquid casting is progressively deposited in the mold and at each instant before the casting jet comes into contact with the shaped surface, it is deposited on the shaped surface and above the casting jet liquid a compound that contains an element that reduces the surface tension of liquid cast iron.
    [0019] According to particular embodiments, the method according to the invention may consist of one or more of the following characteristics:
    [0020] - the element that reduces the surface tension of the liquid cast iron is chosen from sulfur and selenium, or a combination of these two elements;
    [0021] - the inoculant from stage C) and the element that reduces the surface tension of the liquid cast iron are simultaneously deposited on the shaped surface;
    [0022] - the element that reduces the surface tension of the cast iron is sulfur and the total amount of elemental sulfur added during stage D) is comprised between 0.004% and 0.05% of the total mass of cast iron required to manufacture the tubular element;
    [0023] - the sulfur that reduces the surface tension of the liquid cast iron is added during stage C) and is included in the inoculant, the total amount of sulfur being comprised between 4% and 10% by weight of elemental sulfur with respect to weight total inoculant;
    [0024] - the sulfur deposited on the surface of form before pouring the liquid cast into the mold is sulfur in elemental form or FeS;
    [0025] - the weight of inoculant used during the manufacture of the tubular element is comprised between 0.10% and 0.50%, preferably between 0.25% and 0.35%, of the weight of the tubular element; Y
    [0026] - the magnesium content of the cast iron before inoculation is between 0.008% and 0.07%.
    [0027] Brief description of the drawings
    [0028] The invention will be better understood by reading the following description, given solely by way of example and made with reference to the single figure, which is a schematic view of an embodiment of a manufacturing installation for a pipe element used for a method according to the invention.
    [0029] [Fig 1] The single figure represents a manufacturing facility for a spheroidal graphite cast iron tube, designated by general reference 2.
    [0030] The installation 2 serves to manufacture by centrifugation the pipe elements 4, such as tubes. The pipe element 4 forms an object or a base body 6 of spheroidal graphite cast iron.
    [0031] Installation 2 comprises a feeding bag 8, a pouring device 10, a pouring channel 12, an inoculation device 14, a rotary mold 16, a cooling device 18 and an extraction device 20. Installation 2 further comprises a heat treatment furnace 22.
    [0032] Installation 2 also comprises a sulfur supply device 80.
    [0033] The feed bag 8 is a refractory crucible containing liquid metal, such as foundry.
    [0034] The pouring device 10 or pouring container, also called a "basket", has a volume corresponding to the quantity of liquid metal necessary to manufacture one or more base bodies 6. The pouring device 10 is tiltable in a position to pour the liquid metal in chute 12.
    [0035] The pouring channel 12 conducts the liquid metal from the pouring device 10 to the rotary mold 16. The pouring channel 12 comprises an inlet 24 located near the pouring device 10 and an outlet 26 extending into the mold 16 and through which a stream of liquid casting is poured into the mold. The runner 12 is inclined with respect to the horizontal so that its outlet 26 is lower than the inlet 24, thus allowing the liquid melt to flow by gravity.
    [0036] The rotary mold 16, also called the "casing", has a shape with symmetry of revolution, in the present example generally cylindrical, with an XX axis, inclined with respect to the horizontal so that it is parallel to the pouring channel 12. In which below, the terms "axially" and "radially" will be used with reference to this XX axis. The mold 16 has an inner surface or shaped surface 28, which is the negative surface of the base body 6, as well as a cylindrical outer surface 30. The shaped surface 28 is provided with a controlled roughness called "peening", which allows the liquid metal to rotate as it is poured into the mold 16.
    [0037] The mold 16 comprises a bonded tip end 32, rotated towards the inlet 24, and a gear tip end 34, which is rotated in the opposite direction to the inlet 24 and is provided with a core (not shown). The attached tip end 32 forms the attached tip of the base body 6, while the gear end 34 forms the gear tip of the base body 6.
    [0038] The mold 16 can be driven in rotation about the X-X axis. Furthermore, the mold 16 can be driven in translation along the axis XX between a start position of the casting, in which the outlet 26 is opposite the end of gear tip 34, and an end position of the casting, in the that outlet 26 is opposite attached tip end 32.
    [0039] The cooling device 18 comprises an irrigation means that is adapted to project cooling liquid, for example water, onto the outer surface 30 of the mold 16. The extraction device 20 is adapted to axially extract from the mold 16 the slab of the body of base 6 obtained after pouring the liquid metal into the mold.
    [0040] The pouring 10, cooling 18 and extraction 20 devices, the feeding bag 8 as well as the pouring channel 12 are known per se and are not described in more detail. The mold 16 is, for example, completely made of steel, in particular forged.
    [0041] The sulfur supply device 80 comprises a sulfur reservoir 82 and a sulfur introduction means 84, for example a conduit. The sulfur supply device 80 is adapted to introduce sulfur into the liquid cast iron poured onto the surface of form 28.
    [0042] Between the casting start position and the casting end position of the liquid cast iron in the mold, the sulfur introducing means 84 is adapted to deposit sulfur on the form surface 28 upstream of the jet of liquid cast iron poured into the mold. mold and before the liquid cast iron comes into contact with the surface of the shape 28. In other words, the liquid cast is deposited on the surface of the shape 28 only after the previous deposit of the element thereon lowers the surface tension of the liquid casting.
    [0043] For this purpose, the sulfur introduction means 84 open into the mold at a point remote from the outlet 26 of the pouring channel 12, thus further up in the flow direction of the liquid metal in the mold.
    [0044] In this case, the sulfur supply device 80 is adapted to deposit sulfur simultaneously and in combination with the deposition of an inoculating agent 90 by the inoculation device 14.
    [0045] For this purpose, the installation 2 may comprise an inoculant tank comprising an inoculant that is constituted on the one hand by the inoculating agent 90, in particular based on ferrosilicon, and on the other hand by sulfur in elemental form or in the form of FeS. In the present description, the term "inoculant" is defined, therefore, as all the agents or elements used during inoculation, including sulfur in elemental form or in the form of FeS, and the term "inoculating agent 90" It is defined as all the elements used for the inoculation itself, except for sulfur in elemental or combined form.
    [0046] The weight of inoculant used during the manufacture of the tubular member is comprised between 0.10% and 0.50%, preferably between 0.25% and 0.35%, of the weight of the tubular member.
    [0047] Alternatively, the inoculating agent 90 and the element that reduces the surface tension of the liquid cast iron can be deposited separately in the mold.
    [0048] The manufacture of the object or the base body 6 according to the invention by means of the installation 2 is carried out as follows.
    [0049] The manufacturing procedure applied is a procedure that has the characteristics of the manufacturing procedure called "DeLavaud".
    [0050] Liquid melt is introduced into the feeding bag 8. The liquid melt in the bag 8 is such that the object or base body 6 obtained with the manufacturing process according to the invention has the desired composition, reduced by the components provided by the device inoculation 14 and by the sulfur supply device 80.
    [0051] The liquid cast iron, corresponding to the amount of cast iron necessary to manufacture the base body 6, is introduced into the pouring device 10 through the feeding bag 8.
    [0052] The mold 16 is driven in rotation around the X-X axis and brought to its initial casting position. In this position, the shape surface 28 of the mold 16 is not covered with temporary materials and, in particular, is devoid of any temporary heat insulator or temporary refractory material.
    [0053] Subsequently, the liquid cast iron is poured from the pouring device 10 into the pouring channel 12 and flows along it.
    [0054] Advantageously, the magnesium content of the cast iron before inoculation is between 0.008% and 0.07% by weight. This limits, during the casting of the liquid iron in the mold, the reaction of the magnesium with the sulfur that will have been deposited in the mold before the casting of the iron and thus allows the sulfur to act as a reducer of the surface tension of the iron. liquid casting.
    [0055] Just before the liquid cast iron reaches the outlet of the runner 12, and generally between the start of the pouring of the liquid cast into the runner 12 and the arrival of the liquid cast iron at the outlet of the runner 12, the inoculating device 14 begins to deposit an inoculating agent 90, for example a FeSi-based powder, on the form surface 28 of the mold 16. Simultaneously, the sulfur supply device 80 also disposes sulfur on the form surface 28, providing sulfur in elemental form or in the form of FeS.
    [0056] For this purpose, the sulfur supply device 80 is connected to the inoculation device 14 and the sulfur is deposited simultaneously with the inoculating agent and before the liquid melt comes into contact with the surface of the form 28. Preferably, the Sulfur delivery device 80 is part of the inoculation device 14 and the inoculant used for the inoculation contains an adapted amount of sulfur, as defined below.
    [0057] Liquid cast iron is poured into mold 16 at gear tip end 34, coated with inoculating agent and sulfur.
    [0058] Successively, the mold 16 is brought into its final casting position while the liquid cast iron is progressively poured onto the form surface 28 of the mold and, at any time, before the liquid cast comes into contact with the form surface 28. , the inoculating agent and sulfur are deposited on the shape surface 28 at the site of imminent contact between the shape surface 28 and the liquid melt.
    [0059] To this end, the inoculation device 14 and the sulfur supply device 80 open into the mold at a point remote from the outlet 26 of the liquid cast iron from the pouring channel 12, therefore, above considering the sense casting of the liquid cast between the gear tip end 34 and the attached tip end 32 of the mold.
    [0060] Before and during the casting stage, apart from the inoculating agent and sulfur, the shape surface 28 of the mold 16 is not covered with other temporary materials and, in particular, it is devoid of temporary heat insulator or temporary refractory material such as , for example, the one used during casting procedures called "Wetspray".
    [0061] During the entire duration of the casting, the mold 16 is cooled by the cooling device 18. The liquid cast iron in the mold 16 is pressed against the surface 28 by centrifugation, solidifies and forms a slab 100 of the body base 6.
    [0062] The blank 100 from the base body 6 is then removed from the mold 16 by the removal device 20.
    [0063] Next, the slab 100 of the base body 6 is subjected to a heat treatment in the heat treatment furnace 22, and after the heat treatment, the base body 6 is obtained.
    [0064] The total amount of sulfur added by the sulfur supply device 80 is comprised between 4% and 10% by weight of elemental sulfur with respect to the total weight of the inoculant. The total weight of the inoculant here comprises the inoculating agent 90 as well as the sulfur deposited simultaneously with the inoculating agent, the sulfur being added in elemental form or in the form of FeS.
    [0065] The fact of adding sulfur to the liquid iron at a moment close to its solidification allows to reduce the surface tension of the liquid iron and this by limiting the interaction of the sulfur with other components of the iron, such as magnesium.
    [0066] Furthermore, the total amount of elemental sulfur added in the mold is comprised between 0.004% and 0.05% of the total mass of liquid cast iron required for the manufacture of the tubular element.
    [0067] This prevents the casting from reaching sulfur contents detrimental to stability.
    [0068] Also, the oxygen content of the inoculant can be 0%.
    [0069] Alternatively, instead of sulfur, other elements that reduce surface tension can be used, such as selenium.
    [0070] The method and the installation according to the invention make it possible to efficiently and economically reduce the formation of pitting during the manufacture of tubular articles of spheroidal graphite cast iron by centrifugation.
    [0071] Example:
    [0072] This example has made it possible to compare ductile iron pipes manufactured according to a classical centrifugation procedure called "Reference" (see Table 1), with ductile iron pipes manufactured according to the method according to the invention called "Invention" (see Table 2) . In both cases, the ductile iron cast in the mold had the same chemical composition and the rotary mold used was the same.
    [0073] In the classical centrifugation procedure used to obtain the tubes of Table 1, the rotary mold had a shaped surface devoid of heat insulator or temporary refractory material and the inoculant deposited on the surface just before casting the liquid cast into the The mold was a traditional inoculant that had the following composition in percentages by weight: approximately 66% CaSi alloy approximately 2% CaF2 approximately 1% MgF2 approximately 32% FeSi65 (ferrosilicon with 65% Si) , the total being 100%.
    [0074] In the centrifugation process according to the invention, the rotary mold had a shaped surface devoid of heat insulator or temporary refractory material and the inoculant deposited on the surface upstream of the jet of liquid melt poured into the mold was an inoculant that had the following composition in percentages by weight: 80% FeSi 20% FeS.
    [0075] In both cases, the inoculant was introduced into the mold in the same way and in the same proportions. A series of tubes was thus manufactured in each case and the number of pits observed was determined by visual inspection of a part of the outer surface of the tube corresponding to a 10 cm x 6 cm rectangle. The results obtained in each of the cases are presented in the following two tables.
    [0077] [Table 1]
    [0079]
    [0081] Table 1: Reference
    [0082] [Table 2]
    [0084]
    [0087] Table 2: Invention
    [0089] It is observed that the tubes manufactured with the method according to the invention do not show pinholes, unlike those manufactured according to the classical centrifugation method. The addition of sulfur in the mold before casting the foundry, according to the process according to the invention, has therefore made it possible to considerably reduce, and even eliminate, pitting on the outer surface of the tubes.
    权利要求:
    Claims (8)
    [1]
    1. Process for the manufacture of a spheroidal graphite cast iron tubular element by centrifugation, in particular a "Delavaud" type process, comprising the following steps:
    A) - a rotary mold (16) is supplied having a shaped surface (28) of the tubular element, the shaped surface being devoid of temporary thermal insulator or temporary refractory material,
    B) - a casting container (10) containing liquid iron is supplied,
    C) - the inoculant is deposited on the surface of form (28),
    D) - the liquid iron is poured into the mold in the form of a jet of liquid iron deposited along the rotary mold (16) on the surface devoid of temporary thermal insulation or temporary refractory material and provided with inoculant, producing the inoculation of the casting when it comes into contact with the inoculant arranged on the form surface,
    E) - the liquid cast iron poured into the mold solidifies and the rough tubular element is obtained, characterized in that, in step D), while the liquid cast iron is progressively deposited in the mold and at each instant before the jet of When the melt comes into contact with the shaped surface, a compound containing an element that reduces the surface tension of the liquid iron is deposited on the shaped surface 28 and upstream of the jet of liquid iron.
    [2]
    2. Process according to claim 1, in which the element that reduces the surface tension of the liquid cast iron is selected from sulfur and selenium, or a combination of these two elements.
    [3]
    Process according to claim 1 or 2, in which the inoculant from step C) and the element that reduces the surface tension of the liquid cast iron are simultaneously deposited on the shaped surface (28).
    [4]
    4. Process according to any one of claims 1 to 3, in which the element that reduces the surface tension of the casting is sulfur and the total amount of elemental sulfur added during stage D) is between 0.004% and 0, 05% of the total mass of the casting necessary to manufacture the tubular element.
    [5]
    5. Process according to claim 4, in which the sulfur that reduces the surface tension of the liquid foundry is added during step C) and is included in the inoculant, the total amount of sulfur added being between 4% and 10% by weight of elemental sulfur with respect to the total weight of the inoculant.
    [6]
    6. Process according to claim 4 or 5, wherein the sulfur deposited on the form surface (28) before pouring the liquid cast into the mold is sulfur in elemental form or FeS.
    [7]
    Process according to any of the preceding claims, in which the weight of inoculant used during the manufacture of the tubular element is between 0.10% and 0.50%, preferably between 0.25% and 0 35% of the weight of the tubular element.
    [8]
    8. Process according to any of the preceding claims, in which the magnesium number of the cast iron before inoculation is between 0.008% and 0.07%.
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    同族专利:
    公开号 | 公开日
    FR3099716B1|2021-08-27|
    DE102020120272A1|2021-02-11|
    FR3099716A1|2021-02-12|
    ES2804651R1|2021-04-16|
    AT522948A2|2021-03-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US3415307A|1966-03-03|1968-12-10|United States Pipe Foundry|Process for casting ductile iron|
    JPS60250865A|1984-05-28|1985-12-11|Kubota Ltd|Production of cv graphite cast iron pipe|
    NO306169B1|1997-12-08|1999-09-27|Elkem Materials|Cast iron grafting agent and method of making grafting agent|
    NO20045611D0|2004-12-23|2004-12-23|Elkem Materials|Modifying agents for cast iron|
    NO20161091A1|2016-06-30|2018-01-01|Elkem As|Cast Iron Inoculant and Method for Production of Cast Iron Inoculant|
    WO2018028125A1|2016-08-10|2018-02-15|中原内配集团股份有限公司|Needle-shaped cylinder liner and preparation method therefor, and coating liquid for preparing needle-shaped cylinder liner|
    FR3060607B1|2016-12-19|2021-09-10|Saint Gobain Pont A Mousson|SPHEROIDAL GRAPHITE CAST IRON, CORRESPONDING ELEMENT AND MANUFACTURING PROCESS|
    CN109590452B|2019-01-23|2021-05-11|铜陵市大成轧辊有限责任公司|Double-base composite roller preparation process based on centrifugal electroslag casting|
    法律状态:
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    优先权:
    申请号 | 申请日 | 专利标题
    FR1909076A|FR3099716B1|2019-08-08|2019-08-08|Manufacturing process of a tubular element|
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