EP0529943A2 - Laminoir continu pour tubes en acier sans soudure - Google Patents

Laminoir continu pour tubes en acier sans soudure Download PDF

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Publication number
EP0529943A2
EP0529943A2 EP92307612A EP92307612A EP0529943A2 EP 0529943 A2 EP0529943 A2 EP 0529943A2 EP 92307612 A EP92307612 A EP 92307612A EP 92307612 A EP92307612 A EP 92307612A EP 0529943 A2 EP0529943 A2 EP 0529943A2
Authority
EP
European Patent Office
Prior art keywords
roll
groove
rolls
stand
mandrel mill
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP92307612A
Other languages
German (de)
English (en)
Other versions
EP0529943A3 (en
Inventor
Toshio C/O Technical Research Division Imae
Hiromu c/o Chita Works Oka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
Kawasaki Steel Corp
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 Kawasaki Steel Corp filed Critical Kawasaki Steel Corp
Publication of EP0529943A2 publication Critical patent/EP0529943A2/fr
Publication of EP0529943A3 publication Critical patent/EP0529943A3/en
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • B21B17/02—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, i.e. the mandrel rod contacts the rolled tube over the rod length
    • B21B17/04—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, i.e. the mandrel rod contacts the rolled tube over the rod length in a continuous process

Definitions

  • the present invention relates to a method for preventing defects such as holes from being formed on surfaces of blank tubes manufactured by mandrel mill, wherein the holes are produced during the manufacturing of the seamless steel tubes, and more particularly during the manufacturing seamless steel tubes made of a high alloy steel such as stainless steel.
  • the mandrel mill employed in this circumstance normally comprises a plurality of--from five to eight--roll stands 1 configuring a roll groove having a plurality of rolls 2 and 2′ in alternate pairs arranged horizontally and vertically.
  • These plurality of grooved roll stands are disposed orthogonally about a rolling shaft, and a mandrel bar 3 is disposed within a roll groove formed by roll stands 1. The inner surface of the blank tube 4 is rolled by the mandrel bar 3.
  • the wall thickness of the blank tube is reduced at the entrance of the mandrel mill so as to reduce the rolling reduction of each stand of the mill.
  • rolling reduction on the blank tube by the piercing machine is limited and therefore the wall thickness of the blank tube cannot be reduced below a lower limit. In the above situation, it is difficult to roll blank tubes with a thin wall thickness.
  • an object of the present invention is to overcome the above described problems of the mandrel mill and prevent the "hole defect.”
  • the present invention is directed toward a roll groove design of a row of stands consecutively disposed in the mandrel mill to prevent the "hole defect" produced during the rolling process.
  • a mandrel mill for rolling seamless steel tubes which comprises a plurality of roll stands each having a pair of rolls defining a roll groove therebetween, the rolls being arranged such that the axis of the rolls of each roll stand is orthogonal to the axis of the rolls of the adjacent roll stand, and a mandrel bar disposed in the roll groove configured by the roll stands wherein the ratio between the radius of curvature of groove bottom and a distance between the groove bottom of the roll groove of a first stand ranges from 0.46 to 0.54.
  • a mandrel mill for rolling seamless steel tubes comprising a plurality of roll stands each having a pair of rolls defining a roll groove therebetween, the rolls being arranged such that the axis of the rolls of each roll stand is orthogonal to the axis of the rolls of the adjacent roll stand, and a mandrel bar disposed in the roll groove configured by the roll stands wherein the ratio between the radius of curvature of groove bottom and a distance between the groove bottom of the roll groove of a second stand ranges from 0.48 to 0.52.
  • a mandrel mill for rolling seamless steel tubes comprising a plurality of roll stands each having a pair of rolls defining a roll groove therebetween, the rolls being arranged such that the axis of the rolls of each roll stand is orthogonal to the axis of the rolls of the adjacent roll stands, and a mandrel bar disposed in the roll groove configured by the roll stands wherein the ratio between the radius of curvature of groove bottom and a distance between the groove bottom of the roll groove of the first stand ranges from 0.46 to 0.54, and that of the second stand ranges from 0.48 to 0.52.
  • FIG. 1 is a cross sectional view of a roll groove defined by a pair of forming rolls according to the present invention.
  • FIG. 2 illustrates a rolling reduction which becomes smaller at the bottom center of a groove and larger at both sides of the center in the third stand of a mandrel mill.
  • FIG. 3 illustrates the relation between a ratio of the groove bottom radius of curvature and a distance of the groove bottom of a pair of rolls and a ratio of defect occurrence.
  • FIG. 4 is a schematic drawing of a mandrel mill.
  • FIG. 5 is a diagram illustrating hot working characteristics.
  • FIG. 2 illustrates an embodiment of the present invention in which the rolling reduction of both sides of the bottom center groove portion is greater than that of the center groove.
  • reference numerals 2,2′ indicate a roll groove defined by a pair of rolls
  • reference numeral 3 indicates a mandrel bar
  • reference numeral 4 indicates a blank tube (a portion filled by slant bars in the FIG. 2).
  • Reference numeral 4a indicates the thinnest portion of the blank tube wall thickness, which is also a roll bottom center groove portion in the first stand (the first stand refers to stand No.1 in FIG. 2).
  • Reference numeral 4b indicates both sides of the bottom center groove portion 4a.
  • Reference numerals 11, 12, and 13 indicate roll grooves of the first, the second, and the third stands, respectively.
  • the shape of the roll groove 11 of the first stand is normally elliptical and the mandrel bar 3 substantially round.
  • the wall thickness of the tube 4 in the circumferential direction at the exit area of the first stand becomes thinnest in the roll bottom center groove portion 4a, and becomes thicker as you move away from the bottom center groove.
  • FIG. 2(b) in the rolling process at the second stand, the wall-thickness distribution of the thinnest tube wall of the bottom center portion 4a and both sides 4b from the center portion rolled by the first stand can be maintained even after the tube passes the second stand because the thinner portion 4a and thicker portions 4b do not suffer reduction from the roll groove 12 of the second stand.
  • the roll groove 13 is substantially round so as to provide a uniform distribution of the tube-wall-thickness in the circumferential direction.
  • the distribution of the wall thickness at the exit area of the first stand shows that the bottom center groove 4a is thinner and both sides 4b, from the center groove, are thicker.
  • the roll reductions of both sides 4b are greater than that of the center portion 4a in the third stand.
  • the wall thickness in the circumferential direction is thinnest in the tube bottom groove area and as the area goes away from the bottom center groove, the thickness increases in the second stand.
  • the groove bottom portion rolled by the second stand does not suffer reduction in the third stand, in which the wall-thickness distribution of these portion can be maintained after the tube passes the third stand.
  • the roll groove is substantially round to provide a uniform distribution of the tube-wall-thickness in the circumferential direction.
  • the distribution of wall thickness at the exit area of the second stand shows that the wall thickness of the groove bottom is thinner and that of both sides from the groove bottom is thicker.
  • the rolling reduction of both sides from the groove bottom center portion is greater than that of the groove bottom portion, which causes the "hole defect" due to the same reason as described above.
  • the roll groove in the finishing stands of the mandrel mill is designed such that the groove bottom portion is substantially round.
  • the above described finishing stands are disposed between the fourth stand and the sixth or eighth stands.
  • the rolling reduction of both sides from the groove bottom center portion has to be greater than that of the groove bottom portion to unify the wall thickness distribution in either one of the succeeding stands located after the above described stand having the elliptical-shaped roll groove.
  • the present invention has proposed a mandrel mill having a roll groove in which, as is shown in the representing illustration of FIG. 1, the groove bottom radius of curvature R1 in the first stand ranges from 0.46 to 0.54 of the groove bottom distance B of the pair of rolls, and the groove bottom radius of curvature R1 in the second stand ranges from 0.48 to 0.52 of the groove bottom distance B of the pair of rolls.
  • the rolling reduction in the circumferential direction of the groove bottom in the third stand can be unified by designing the groove bottom radius of curvature of the roll groove in the first stand to range from 0.46 to 0.54 of the distance between the groove bottom of the pair of rolls in the first stand.
  • the groove bottom radius of curvature of the roll groove in the first stand can range from 0.46 to 0.54 of the distance between the groove bottom of the pair of rolls in the first stand.
  • the rolling reduction in the circumferential direction of the groove bottom in the fourth stand can be unified by designing the groove bottom radius of curvature of the roll groove in the second stand to range from 0.48 to 0.52 of the distance between the groove bottom of the pair of rolls in the second stand.
  • the occurrence of a "hole defect" can be practically eliminated.
  • the ratios of the groove bottom radius of curvature R1 and the distance B between the groove bottom of the pair of rolls are determined as ranging from 0.46 to 0.54 in the first stand and from 0.48 to 0.52 in the second stand.
  • Rolling conditions and results of a mandrel mill using a tube material of a plain carbon steel according to the present invention are exhibited in Tables 1 and 2 respectively.
  • the ratios between the groove bottom radius of curvature of the roll groove and the distance between the groove bottom formed by the pair of rolls in the first and second stands are set as 0.54 and 0.52 respectively.
  • the ratios between the groove bottom radius of curvature of the roll groove and the distance between the groove bottom formed by the pair of rolls in the first and second stands are set as 0.6 and 0.55 respectively.
  • plain carbon steel with dimension of the outer diameter of 180 mm and wall thickness of 4 mm at the exit of the mandrel mill can be manufactured without "hole defect.”
  • Rolling conditions and results of a mandrel mill using a tube material of 13 % Cr-steel according to the present invention are exhibited in Tables 3 and 4, respectively.
  • the ratios between the groove bottom radius of curvature of the roll groove and the distance between the groove bottom formed by the pair of rolls in the first and second stands are set as 0.54 and 0.52, respectively.
  • the ratios between the groove bottom radius of curvature of the roll groove and the distance between the groove bottom formed by the pair of rolls in the first and second stands are set as 0.6 and 0.55, respectively.
  • a "hole defect" which conventionally has occurred at the groove bottom center portion in a roll groove, can be successfully prevented by designing the groove bottom radius of curvature of the roll groove at the first and second stands in the mandrel mill.
  • a remarkable effect is obtained for preventing a "hole defect" in mandrel mill rolling especially for tubes with thin wall-thickness and for a high alloy steel having an inferior deformability.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
  • Control Of Metal Rolling (AREA)
EP19920307612 1991-08-22 1992-08-20 Mandrel mill for seamless steel tubes Withdrawn EP0529943A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP3233835A JPH07102369B2 (ja) 1991-08-22 1991-08-22 マンドレルミル
JP233835/91 1991-08-22

Publications (2)

Publication Number Publication Date
EP0529943A2 true EP0529943A2 (fr) 1993-03-03
EP0529943A3 EP0529943A3 (en) 1993-06-30

Family

ID=16961316

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920307612 Withdrawn EP0529943A3 (en) 1991-08-22 1992-08-20 Mandrel mill for seamless steel tubes

Country Status (3)

Country Link
EP (1) EP0529943A3 (fr)
JP (1) JPH07102369B2 (fr)
CA (1) CA2076402C (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114309076A (zh) * 2020-09-30 2022-04-12 宝武特种冶金有限公司 一种用于无缝钢管冷轧机环孔型的精度修整方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008119706A (ja) 2006-11-09 2008-05-29 Sumitomo Metal Ind Ltd マンドレルミルおよびその操業方法ならびに継目無管の製造方法
JP5062522B2 (ja) * 2007-05-31 2012-10-31 住友金属工業株式会社 マンドレルミル及び継目無管の製造方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58224155A (ja) * 1982-06-19 1983-12-26 Kawasaki Steel Corp ２相ステンレス継目無鋼管およびその製造方法
JPS60106603A (ja) * 1983-11-15 1985-06-12 Kawasaki Steel Corp 継目無鋼管の製造方法
JPS6384720A (ja) * 1986-09-30 1988-04-15 Kawasaki Steel Corp マンドレルミルによる継目無管製造方法
JPH01186205A (ja) * 1988-01-22 1989-07-25 Nippon Steel Corp シームレス鋼管製造用マンドレルミル
JPH01284411A (ja) * 1988-05-09 1989-11-15 Nkk Corp マンドレルミル用のカリバーロール

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58224155A (ja) * 1982-06-19 1983-12-26 Kawasaki Steel Corp ２相ステンレス継目無鋼管およびその製造方法
JPS60106603A (ja) * 1983-11-15 1985-06-12 Kawasaki Steel Corp 継目無鋼管の製造方法
JPS6384720A (ja) * 1986-09-30 1988-04-15 Kawasaki Steel Corp マンドレルミルによる継目無管製造方法
JPH01186205A (ja) * 1988-01-22 1989-07-25 Nippon Steel Corp シームレス鋼管製造用マンドレルミル
JPH01284411A (ja) * 1988-05-09 1989-11-15 Nkk Corp マンドレルミル用のカリバーロール

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
DATABASE WPIL Section Ch, Week 8406, Derwent Publications Ltd., London, GB; Class M27, AN 84-033970 (06) & JP-A-58 224 155 (KAWASAKI STEEL) 26 December 1983 *
H.NEUMANN ET AL.: 'Stahlrohrherstellung' 1970 , 3RD ED., DEUTSCHER VERLAG FÜR GRUNDSTOFFINDUSTRIE , LEIPZIG, DD *
PATENT ABSTRACTS OF JAPAN vol. 12, no. 311 (M-734)24 August 1988 & JP-A-63 084 720 ( KAWASAKI STEEL ) 15 April 1988 *
PATENT ABSTRACTS OF JAPAN vol. 13, no. 473 (M-884)26 October 1989 & JP-A-01 186 205 ( NIPPON STEEL ) 25 July 1989 *
PATENT ABSTRACTS OF JAPAN vol. 14, no. 58 (M-930)2 February 1990 & JP-A-01 284 411 ( NKK ) 15 November 1989 *
PATENT ABSTRACTS OF JAPAN vol. 9, no. 256 (M-421)15 October 1985 & JP-A-60 106 603 ( KAWASAKI SEITETSU ) 12 June 1985 *
W.T.LANKFORD ET AL.: 'The Making, Shaping and Treating of Steel' 1985 , 10TH ED., AISE , PITTSBURGH, PA, US *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114309076A (zh) * 2020-09-30 2022-04-12 宝武特种冶金有限公司 一种用于无缝钢管冷轧机环孔型的精度修整方法
CN114309076B (zh) * 2020-09-30 2023-05-16 宝武特种冶金有限公司 一种用于无缝钢管冷轧机环孔型的精度修整方法

Also Published As

Publication number Publication date
CA2076402A1 (fr) 1993-02-23
CA2076402C (fr) 1996-03-05
JPH0550115A (ja) 1993-03-02
EP0529943A3 (en) 1993-06-30
JPH07102369B2 (ja) 1995-11-08

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