WO2020189140A1 - Procédé de fabrication d'un tube en acier carré sans soudure - Google Patents

Procédé de fabrication d'un tube en acier carré sans soudure Download PDF

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Publication number
WO2020189140A1
WO2020189140A1 PCT/JP2020/006235 JP2020006235W WO2020189140A1 WO 2020189140 A1 WO2020189140 A1 WO 2020189140A1 JP 2020006235 W JP2020006235 W JP 2020006235W WO 2020189140 A1 WO2020189140 A1 WO 2020189140A1
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WO
WIPO (PCT)
Prior art keywords
square
steel pipe
stand
square steel
outer diameter
Prior art date
Application number
PCT/JP2020/006235
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English (en)
Japanese (ja)
Inventor
吉田　竜也
Original Assignee
Ｊｆｅスチール株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ｊｆｅスチール株式会社 filed Critical Ｊｆｅスチール株式会社
Priority to CN202080018676.7A priority Critical patent/CN113543901B/zh
Priority to KR1020217030004A priority patent/KR102476860B1/ko
Priority to JP2020522393A priority patent/JP6741192B1/ja
Publication of WO2020189140A1 publication Critical patent/WO2020189140A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B17/00—Tube-rolling by rollers of which the axes are arranged essentially perpendicular to the axis of the work, e.g. "axial" tube-rolling
    • B21B17/08—Tube-rolling by rollers of which the axes are arranged essentially perpendicular to the axis of the work, e.g. "axial" tube-rolling with mandrel having one or more protrusions, i.e. only the mandrel plugs contact the rolled tube; Press-piercing mills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B17/00—Tube-rolling by rollers of which the axes are arranged essentially perpendicular to the axis of the work, e.g. "axial" tube-rolling
    • B21B17/14—Tube-rolling by rollers of which the axes are arranged essentially perpendicular to the axis of the work, e.g. "axial" tube-rolling without mandrel, e.g. stretch-reducing mills
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/15—Making tubes of special shape; Making tube fittings

Definitions

  • the present invention relates to a method for manufacturing a seamless square steel pipe or tube, and in particular, a seam capable of obtaining a seamless square steel pipe having a corner S value equivalent to that of the conventional one while reducing the equipment load. Regarding the manufacturing method of a square steel pipe.
  • the seamless square steel pipe has a feature that the wall thickness can be increased and high strength can be obtained as compared with the square welded steel pipe. Therefore, the seamless square steel pipe is used especially for building materials.
  • a method by hot seamless forming has been proposed.
  • a billet as a starting material is heated in a heating furnace and then perforated with a piercer to form a cylindrical raw tube.
  • the cylindrical pipe is treated with an elongator mill (for pipe expansion), a plug mill (for stretching), a reeler mill (for polishing pipe), etc., then heated in a reheating furnace, and then a standard rolling mill (sizing mill). It is hot-rolled with a seamless square steel pipe.
  • FIG. 1 is a schematic view showing an example of a rolling stand configuration in a standard rolling mill 10 used for manufacturing a seamless square steel pipe.
  • the standard rolling mill 10 is a rolling mill in which a plurality of rolling stands are arranged in tandem.
  • a stand 11 having a roll having a circular caliber (hole type) is provided in the rear stage.
  • square forming stands 12 having rolls having square calibers are arranged respectively.
  • the square cross section is formed by the square forming stand 12 in the rear stage.
  • the standard rolling mill 10 illustrated in FIG. 1 has a 2-roll, 8-stand configuration, and the latter 4 stands are square forming stands.
  • the corners of the seamless square steel pipe have a certain degree of roundness. Then, as one of the indexes for evaluating the roundness of the corner portion, the S value defined as "corner dimension" in JIS G3466 is used.
  • a seamless square steel pipe is required to have a sharp corner shape, that is, a small S value. Therefore, a method for manufacturing a seamless square steel pipe having a small S value is being studied.
  • Patent Document 2 the rolling conditions are controlled so that the peripheral length reduction rate (perimeter reduction rate), the S value, and the wall thickness t in the first square forming stand of the standard rolling mill satisfy a predetermined relationship.
  • a method for obtaining a seamless square steel pipe having a small corner curvature and flat sides has been proposed.
  • the horizontal axis of FIG. 3 is the outer diameter reduction ratio ⁇ r1 in the first square forming stand
  • the vertical axis (left side) is the ratio of the S value to the wall thickness t (S / t).
  • the value of S / t decreases as ⁇ r1 increases. That is, the experimental results show that it is necessary to increase the outer diameter reduction ratio ⁇ r1 in the first square forming stand in order to reduce the S value.
  • the broken line in FIG. 3 shows the load ratio applied to the rolling stand at that time.
  • the load ratio is a relative value of the load applied to the rolling stand, where 1 is the load when ⁇ r1 is 0.2.
  • S / t can be reduced by increasing ⁇ r1, the load applied to the rolling stand is significantly increased accordingly.
  • the seamless square steel pipe is required to have a larger diameter and a thicker wall.
  • the cross-sectional area of the steel pipe increases due to the increase in diameter and wall thickness, the load required for rolling also increases accordingly.
  • the present invention has been made in view of the above-mentioned actual conditions, and even a seamless square steel pipe having a large cross section can be manufactured without increasing the rolling load and achieves a sufficiently small S value. It is an object of the present invention to provide a method for manufacturing a seamless square steel pipe which can be used.
  • the present inventors have conducted a detailed study on the influence of the rolling schedule in the standard rolling mill on the rolling load and the S value. As a result, they have found that the above problem can be solved by controlling the rolling conditions based on a completely different concept from the conventional technique of reducing the S value by making ⁇ r1 extremely large. That is, the gist structure of the present invention is as follows.
  • a method for manufacturing a seamless square steel pipe in which a billet is drilled to form a cylindrical raw pipe, and the cylindrical raw pipe is hot-rolled with a standard rolling mill equipped with a plurality of square forming stands to form a square cylinder.
  • the number n of square forming stands in the standard rolling mill is 3 or more.
  • the outer diameter reduction ratio ⁇ r1 in the first square forming stand, the outer diameter reduction ratio ⁇ r2 in the second square forming stand, and the outer diameter reduction ratio R in the full angle forming stand are the following equations (1) and (2).
  • a method of manufacturing a seamless square steel pipe that satisfies the requirements. ( ⁇ r1 + ⁇ r2) / R ⁇ 0.70 ... (1) ⁇ r2-0.01 ⁇ ⁇ r1 ⁇ ⁇ r2 + 0.01 ... (2)
  • a seamless square steel pipe having a large cross section can be manufactured without increasing the rolling load, and a sufficiently small S value can be achieved. Since the increase in rolling load can be suppressed, according to the method of the present invention, it is possible to manufacture a seamless square steel pipe having a larger cross section and a good square shape by using existing equipment. The industrial significance is extremely great.
  • a seamless square steel pipe is manufactured by drilling a billet into a cylindrical raw pipe and hot rolling the cylindrical raw pipe into a square cylinder with a standard rolling mill equipped with a plurality of square forming stands. To do.
  • the method of perforating the billet to obtain a cylindrical raw tube is not particularly limited, and any method can be used.
  • it can be drilled with a piercer to form a cylindrical raw tube.
  • the temperature on the exit side of the heating furnace is preferably 700 to 1200 ° C.
  • the cylindrical raw pipe Prior to hot rolling by the next standard rolling mill, it is preferable that the cylindrical raw pipe is optionally expanded by an elongator mill, stretched by a plug mill, and polished by a reeler mill.
  • the cylindrical raw pipe is hot-rolled and formed into a square cylinder.
  • a seamless square steel pipe having the final dimensions and cross-sectional shape is obtained.
  • any one can be used as long as the number n of the square forming stands is 3 or more.
  • the upper limit of the number n of the square forming stands is not particularly limited. However, usually, n is preferably 3 or 4, and more preferably 4.
  • the number of rolls per square forming stand is not particularly limited and can be any number. However, in general, it is preferably 2 or 3, and more preferably 2. Further, as shown in FIG. 1, the rolls of the square forming stands are preferably arranged in a direction rotated by 90 ° on a plane perpendicular to the pipe passage direction with respect to the rolls of adjacent square forming stands.
  • the standard rolling mill may be provided with a stand provided with a roll having a circular caliber (hole type) (circular caliber roll) on the upstream side of the square forming stand.
  • the number of stands equipped with the circular caliber roll is not particularly limited. However, usually, it is preferably 3 or 4, and more preferably 4.
  • the outer diameter reduction ratio ⁇ r1 in the first square forming stand, the outer diameter reduction ratio ⁇ r2 in the second square forming stand, and the outer diameter reduction ratio R in the full angle forming stand are as follows (1) and. It is important to control the rolling conditions so as to satisfy the equation (2). ( ⁇ r1 + ⁇ r2) / R ⁇ 0.70 ... (1) ⁇ r2-0.01 ⁇ ⁇ r1 ⁇ ⁇ r2 + 0.01 ... (2)
  • ⁇ r1 (D0-D1) / D0
  • ⁇ r2 (D1-D2)
  • D1 R (D0-Dn) / D0
  • D0 Outer diameter of the pipe before rolling in the first square forming stand
  • ⁇ D1 Outer diameter of the pipe after rolling in the first square forming stand
  • ⁇ D2 Outer diameter of the pipe after rolling in the second square forming stand
  • Diameter / Dn Outer diameter of the rolled pipe at the final square forming stand
  • the outer diameter of the pipe before rolling in the square forming stand means the outer diameter of the pipe on the entrance side of the stand.
  • the outer diameter of the rolled pipe in the square forming stand shall refer to the outer diameter of the pipe on the outlet side of the stand. Therefore, as shown in FIG. 1, D0 is equal to the outer diameter of the cylindrical raw tube before square forming.
  • Dn is the distance between the outer surfaces of the opposing flat portions in the cross section of the square steel pipe.
  • D1 and D2 are the distances between the outer surfaces of the opposing flat portions in the cross section of the steel pipe being formed.
  • ( ⁇ r1 + ⁇ r2) / R is preferably 0.75 or more.
  • the upper limit of ( ⁇ r1 + ⁇ r2) / R is not particularly limited, but is preferably 0.85 or less, and more preferably 0.83 or less.
  • the present invention is not particularly limited, and can be used for manufacturing a seamless square steel pipe having an arbitrary outer diameter and wall thickness.
  • the problem of load on equipment becomes serious when the cross section is large. Therefore, the present invention can be particularly suitably applied to the production of a seamless square steel pipe having a large cross section.
  • the outer diameter of the seamless square steel pipe to be manufactured is 250 mm or more.
  • the thickness of the seamless square steel pipe to be manufactured is 25 mm or more.
  • the upper limit of the outer diameter and the wall thickness of the seamless square steel pipe is not particularly limited, but the outer diameter of the seamless square steel pipe is preferably 360 mm or less. Further, the wall thickness of the seamless square steel pipe is preferably 40 mm or less.
  • the temperature of the material to be rolled is not particularly limited and can be any temperature. However, if the temperature is 600 ° C. or higher, residual strain due to cold working can be suppressed. Therefore, from the viewpoint of material properties, it is preferable that the temperature of the steel pipe as the material to be rolled during hot rolling is 600 ° C. or higher.
  • the upper limit of the temperature is not particularly limited, but if the temperature is 1100 ° C. or lower, the generation of scale on the outer surface of the steel pipe can be suppressed. As a result, it is possible to prevent the occurrence of scratches due to the scale being pushed in during square forming. Therefore, from the viewpoint of improving the appearance quality, the temperature is preferably set to 1100 ° C. or lower.
  • the temperature of the material to be rolled refers to the surface temperature of the material to be rolled (steel pipe).
  • a seamless square steel pipe was manufactured by the procedure described below. First, a billet was perforated to form a cylindrical raw tube. After heating the cylindrical raw pipe in a heating furnace, it was hot-rolled in a standard rolling mill equipped with a plurality of square forming stands and formed into a square cylinder to obtain a seamless square steel pipe. In the heating, the temperature on the outlet side of the heating furnace was set to 1000 ° C.
  • the standard rolling mill a machine equipped with two 2-roll type square forming stands was used. Of the two square forming stands, the one on the upstream side is referred to as the first stand, and the one on the downstream side is referred to as the second stand.
  • the molding conditions (outer diameter reduction ratio) in the square molding stand are as shown in Table 1. Then, the rolling load at the first stand and the second stand at that time, and the corner dimension (S value) of the finally obtained seamless square steel pipe were measured. The measurement results are also shown in Table 1.
  • the temperature of the material to be rolled during hot rolling in the square forming stand was 1000 to 900 ° C.
  • the dimensions of the seamless square steel pipe were an outer diameter (side length) of 300 mm and a wall thickness of t: 30 mm.
  • the outer diameter D0 of the cylindrical raw tube was set to 418 mm.
  • ⁇ Load at 1st stand Less than 150 tonf: ⁇ ⁇ Load at 1st stand: 150 tonf or more, less than 160 tonf: ⁇ ⁇ Load at 1st stand: 160 tonf or more: ⁇
  • the S value was also determined based on the following criteria, and the results are also shown in Table 1.
  • 37.5 mm is the allowable range of the S value when the standard S value is 0.75 and the dimensional tolerance is 0.5 t in a steel pipe having a wall thickness of t: 30 mm.
  • Comparative example No. Reference numeral 1 denotes a conventional rolling condition in which the S value is reduced by making ⁇ r1 extremely large.
  • Comparative Example No. 2 is No. ⁇ r1 is reduced as compared with 1. This No. In 2, No. Although the S value was a pass judgment as in No. 1, the rolling load was still large because the condition of Eq. (2) was not satisfied.
  • Comparative Example No. No. 4 sets ⁇ r1 to No. This is an example of further reduction from 3.
  • No. 4 satisfies the condition of the equation (2), but does not satisfy the condition of the equation (1).
  • the S value increased significantly.
  • the S value can be reduced and the rolling load can be reduced by overcoming the conventional technical prejudice and controlling the rolling conditions based on a technical idea completely different from the existing technique.
  • the conflicting demands of restraint can be met.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Metal Rolling (AREA)
  • Control Of Metal Rolling (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

L'objet de la présente invention est de fournir un procédé de fabrication d'un tube en acier carré sans soudure au moyen duquel il est possible d'obtenir un tube en acier carré sans soudure ayant une valeur de partie de coin S équivalente à celles obtenues dans le passé, tout en réduisant une charge d'équipement.　Dans ce procédé de fabrication d'un tube en acier carré sans soudure par perçage d'une billette pour obtenir un tuyau de matériau de départ cylindrique, et laminage à chaud du tuyau de matériau de départ cylindrique à l'aide d'un laminoir à coffrage fixe pourvu d'une pluralité de supports de moulage carrés pour former un cylindre carré : un nombre n des supports de moulage carrés dans le laminoir de forme fixe est supérieur ou égal à trois ; et un rapport de réduction de diamètre extérieur Δr1 d'un premier support de moulage carré, un rapport de réduction de diamètre externe Δr2 d'un second support de moulage carré, et un rapport de réduction de diamètre externe R de tous les supports de moulage carrés satisfont les formules (1) et (2). (1) (Δr1 + Δr2) / R ≥ 0,70 (2) Δr2 - 0,01 ≤ Δr1 ≤ Δr2 + 0,01
PCT/JP2020/006235 2019-03-15 2020-02-18 Procédé de fabrication d'un tube en acier carré sans soudure WO2020189140A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN202080018676.7A CN113543901B (zh) 2019-03-15 2020-02-18 无缝方形钢管的制造方法
KR1020217030004A KR102476860B1 (ko) 2019-03-15 2020-02-18 이음매 없는 각형 강관의 제조 방법
JP2020522393A JP6741192B1 (ja) 2019-03-15 2020-02-18 継目無角形鋼管の製造方法

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JP2019-048291 2019-03-15
JP2019048291 2019-03-15

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114733911A (zh) * 2022-04-15 2022-07-12 衡阳华菱钢管有限公司 管体加工方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04224022A (ja) * 1990-12-27 1992-08-13 Nippon Steel Corp 角鋼管の成形方法
JPH08164416A (ja) * 1994-12-12 1996-06-25 Kawasaki Steel Corp 鍛接角鋼管の製造方法
JPH10263626A (ja) * 1997-03-24 1998-10-06 Kawasaki Steel Corp 継目無角形鋼管及びその製造方法
JPH11104711A (ja) * 1997-10-03 1999-04-20 Yoshitomi Onoda 継目無角形鋼管の製造方法
JPH11123452A (ja) * 1997-10-24 1999-05-11 Nkk Corp 丸管からの角管製造方法
JP2001353520A (ja) * 2000-06-14 2001-12-25 Nippon Steel Corp 角型鋼管の成形方法

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10258303A (ja) * 1997-03-18 1998-09-29 Kawasaki Steel Corp 継目無角形鋼管の製造方法
JPH11104710A (ja) * 1997-10-03 1999-04-20 Yoshitomi Onoda 継目無角形鋼管の製造方法
JP3496554B2 (ja) * 1999-01-06 2004-02-16 住友金属工業株式会社 溝形鋼の製造方法、粗ユニバーサル圧延機および仕上ユニバーサル圧延機
CN100409953C (zh) * 2004-03-29 2008-08-13 住友金属工业株式会社 管的制造方法及定径轧制装置
EP1738839B1 (fr) * 2005-06-28 2009-08-26 Sumitomo Metal Industries, Ltd. Procédé de laminage à froid pour tubes métalliques
US8912462B2 (en) * 2005-11-11 2014-12-16 Jfe Steel Corporation Method of manufacturing electric resistance welding pipes having excellent characterization of welded seams
AU2006324717B2 (en) * 2005-12-16 2010-09-23 Jfe Steel Corporation Method of manufacturing electric resistance welding pipe having excellent characterization of welded seam
AU2006349207B8 (en) * 2006-10-12 2011-01-20 Jfe Steel Corporation Manufacturing equipment of electric resistance welding pipes having excellent characterization of welded seam
CN102245320B (zh) * 2008-12-24 2015-09-02 新日铁住金株式会社 利用冷轧制造无缝金属管的方法
US9574684B1 (en) * 2009-08-17 2017-02-21 Ati Properties Llc Method for producing cold-worked centrifugal cast composite tubular products
CN202490820U (zh) * 2012-02-27 2012-10-17 浙江健力股份有限公司 GCr15轴承钢管热轧减径装置
CN102873098B (zh) * 2012-09-26 2015-01-21 西北有色金属研究院 一种超薄壁钛管材的制造方法
JP6274452B2 (ja) * 2015-04-06 2018-02-07 Ｊｆｅスチール株式会社 マルテンサイト系高Ｃｒ鋼継目無鋼管の製造方法
CN207271810U (zh) * 2017-09-04 2018-04-27 淮安市振达钢管制造有限公司 一种用于防止轧制大口径薄壁管产生凹面的定心辊新型托辊

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04224022A (ja) * 1990-12-27 1992-08-13 Nippon Steel Corp 角鋼管の成形方法
JPH08164416A (ja) * 1994-12-12 1996-06-25 Kawasaki Steel Corp 鍛接角鋼管の製造方法
JPH10263626A (ja) * 1997-03-24 1998-10-06 Kawasaki Steel Corp 継目無角形鋼管及びその製造方法
JPH11104711A (ja) * 1997-10-03 1999-04-20 Yoshitomi Onoda 継目無角形鋼管の製造方法
JPH11123452A (ja) * 1997-10-24 1999-05-11 Nkk Corp 丸管からの角管製造方法
JP2001353520A (ja) * 2000-06-14 2001-12-25 Nippon Steel Corp 角型鋼管の成形方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114733911A (zh) * 2022-04-15 2022-07-12 衡阳华菱钢管有限公司 管体加工方法

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CN113543901A (zh) 2021-10-22
TWI731615B (zh) 2021-06-21
KR20210127238A (ko) 2021-10-21
TW202039109A (zh) 2020-11-01
KR102476860B1 (ko) 2022-12-12
CN113543901B (zh) 2023-08-04

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