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US20100064753A1 - Mandrel mill, operating method of the same and production method of seamless pipe - Google Patents

Mandrel mill, operating method of the same and production method of seamless pipe Download PDF

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Publication number
US20100064753A1
US20100064753A1 US12/312,423 US31242307A US2010064753A1 US 20100064753 A1 US20100064753 A1 US 20100064753A1 US 31242307 A US31242307 A US 31242307A US 2010064753 A1 US2010064753 A1 US 2010064753A1
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US
United States
Prior art keywords
roll
grooved
stand
groove bottom
hollow shell
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.)
Abandoned
Application number
US12/312,423
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English (en)
Inventor
Kenichi Sasaki
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.)
Nippon Steel Corp
Original Assignee
Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of US20100064753A1 publication Critical patent/US20100064753A1/en
Assigned to SUMITOMO METAL INDUSTRIES, LTD. reassignment SUMITOMO METAL INDUSTRIES, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SASAKI, KENICHI
Abandoned 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B27/00—Rolls, roll alloys or roll fabrication; Lubricating, cooling or heating rolls while in use
    • B21B27/02—Shape or construction of rolls
    • B21B27/03—Sleeved rolls
    • B21B27/035—Rolls for bars, rods, rounds, tubes, wire or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B2267/00—Roll parameters
    • B21B2267/02—Roll dimensions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B2267/00—Roll parameters
    • B21B2267/02—Roll dimensions
    • B21B2267/06—Roll diameter

Definitions

  • the present invention relates to a mandrel mill that does not generate holes, roll slip flaws, cornice flaws, and the like, an operating method of the same, and a production method of a seamless pipe.
  • a mandrel mill that has six to eight units of roll stands, each composed of a pair of upper and lower mill rolls, such that the groove bottom directions of the roll grooves of the anteroposterior stand across from one another at 90°.
  • a hollow shell is continuously elongated by arranging the mandrel bar in a roll groove array formed by the plurality of roll stands.
  • FIG. 3 is a schematic diagram showing an entire configuration of the mandrel mill.
  • the mandrel mill has grooved-roll stands 11 to 14 each composed of a pair of mill rolls 4 , and multiple units (four units in the figure) are provided consecutively so that each roll stand across from each other at 90°.
  • a seamless pipe is produced by inserting a mandrel bar 3 in a hollow shell 2 bored in advance with a piercer, and sequentially rolling and elongating this by the roll stands 11 to 14 .
  • the roll stands provided are called, in the order from mill entry side, a first stand ( 11 in the figure), a second stand ( 12 in the figure), a third stand ( 13 in the figure), and a fourth stand ( 14 in the figure).
  • the wall thickness is first reduced at the first stand.
  • Patent document 1 discloses an invention of a mandrel mill that includes a plurality of consecutively provided grooved-roll stands crossing with each other and rolls a hollow shell with a mandrel bar provided in a roll groove array formed by the grooved-roll stands, wherein the ellipticity of the groove of a first or/and second stand is in the range of 1.25 to 1.40. This prevents a generation of hole occurrence and pipe end cracking.
  • Patent document 2 discloses an invention of a mandrel mill that includes a plurality of grooved-roll stands and rolls a hollow shell with a mandrel bar provided in a roll groove array formed by the grooved-roll stands, wherein the circumferential length of the roll groove of a first stand is at least 1.12 times the hot-finished circumferential length of the pipe on the mill exit side.
  • Patent document 3 discloses an invention of a mandrel mill that includes a plurality of grooved-roll stands and rolls a hollow shell with a mandrel bar provided in a roll groove array formed by the grooved-roll stands, wherein the radius of groove bottom curvature of the roll groove of a first stand is 0.54 times or less the roll groove bottom interval.
  • Patent document 4 discloses an invention of a mandrel mill that includes a plurality of consecutively provided grooved-roll stands and elongates a hollow shell continuously with a mandrel bar provided in a roll groove array formed by the grooved-roll stands.
  • the radius R 1 of the groove bottom curvature of the roll groove of each stand and a displacement-offset-amount S between the groove bottom curvature center and the mill center have a ratio S/R 1 of at least 30, and the ellipticity of a second stand is 1.20 or less.
  • Patent document 1 Japanese Unexamined Patent Publication No. 2001-113306
  • Patent document 2 Japanese Patent Publication No. 2582705
  • Patent document 3 Japanese Examined Patent Publication Hei 7-102369
  • Patent document 4 Japanese Patent Publication No. 2985719
  • Patent document 1 describes that in order to prevent a hole generation on the elongated seamless pipe, it is effective to limit the ellipticity of the groove. However, even though the ellipticity is adjusted, a flaw may occur in some cases on the elongated seamless pipe depending on the offset amount.
  • Patent document 2 discloses a technique that limits the circumferential length of the roll groove of the first stand, or further the second stand of the mandrel mill, within a certain range relative to a hot-finished circumferential length of the pipe at the mill exit side, a suitable gap is secured between the mandrel bar and the inner surface of the hollow shell that is being elongated, thereby preventing missed stripping.
  • ellipticity nor offset, which could cause a flaw to occur on the elongated seamless pipe.
  • Patent document 3 describes that hole occurrence is suppressed. However, even if the offset is reduced, if the ellipticity is not adjusted in an appropriate range, a flaw may occur on the elongated seamless pipe.
  • Patent document 4 describes that in the mandrel mill, by limiting the ellipticity and offset as well within predetermined ranges, it is possible to suppress a generation of the necking phenomenon and reduce the hole occurrence. However, there is no indication of the relationship between the ellipticity and the offset.
  • the present inventors conducted an extensive study to solve the problems of the conventional art, and as a result, have found an effective ellipticity-offset balance for preventing flaw generation on an elongated seamless pipe, resulting in a completion of the present invention. It is an objective of the present invention to provide a mandrel mill with minimized flaw occurrence on an elongated seamless pipe.
  • the gist of the present invention is: a mandrel mill indicated as (1) below; an operating method of the mandrel mill indicated as (2) below; and a production method of a seamless pipe indicated as (3) below.
  • a mandrel mill comprising a plurality of consecutively provided grooved-roll stands and a mandrel bar provided in a roll groove array formed by the grooved-roll stands so as to continuously elongate a hollow shell, characterized in that roll grooves of at least a first stand and a second stand are arranged so as to satisfy conditions represented by the following formulas (1) to (4).
  • a is a ratio of S/R 1 between a groove bottom curvature radius R 1 of each grooved-roll and a displacement-offset-amount S between a groove bottom curvature center and a mill center
  • b is ellipticity
  • An operating method of a mandrel mill including a plurality of consecutively provided grooved-roll stands and a mandrel bar provided in a roll groove array formed by the grooved-roll stands, characterized in that a hollow shell is continuously elongated when a groove bottom curvature radius R 1 , a displacement-offset-amount S, and ellipticity of each of grooved-rolls satisfy conditions represented by the above formulas (1) to (4) in at least a first stand and a second stand, whereby a hole occurrence and flaw generation are prevented.
  • a production method of a seamless pipe using a mandrel mill including a plurality of consecutively provided grooved-roll stands and a mandrel bar provided in a roll groove array formed by the grooved-roll stands, characterized in that a hollow shell is continuously elongated when a groove bottom curvature radius R 1 , a displacement-offset-amount S, and ellipticity of each of grooved-rolls satisfy conditions represented by the above formulas (1) to (4) in at least a first stand and a second stand.
  • a hollow shell is rolled with a good balance between offset and ellipticity, thereby making it possible to suppress the hole occurrence and flaw generation on an elongated seamless pipe. Therefore, flaws such as necking can be suppressed even in the case of rolling a thin wall pipe and a high alloy steel pipe, which are easily subject to defects.
  • the mandrel mill of the present invention is a mandrel mill that includes a plurality of consecutively provided grooved-roll stands and also a mandrel bar provided in a roll groove array formed by the grooved-roll stands so as to continuously elongate a hollow shell.
  • multiple units (four units in the figure) of grooved-roll stands 1 each composed of a pair of mill rolls 4 are provided so as to cross each other at 90°.
  • a seamless pipe is produced by inserting a mandrel bar 3 in a hollow shell 2 bored in advance with a piercer, and sequentially elongating this on the roll stands 11 to 14 .
  • FIG. 4 is a schematic diagram showing a rolling state of a hollow shell in the mandrel mill.
  • (a) to (f) each shows a rolling state of the hollow shell at first to the sixth stands.
  • (b) to (f) each shows a figure with the grooved-rolls omitted.
  • FIG. 4 an example of a mandrel mill with six stands is shown, but the number of the stands is not limited.
  • the rolling is conducted by continuously passing a hollow shell 2 that a mandrel bar 3 is inserted through the pairs of grooved-rolls 4 .
  • the wall thickness and diameter reduce gradually through the stands.
  • a hollow shell 2 is elongated by the grooved-rolls 4 and the mandrel bar 3 .
  • a part of the hollow shell 2 located at a groove bottom portion of each grooved-roll 4 (a portion of contact between each grooved-roll 4 and the hollow shell 2 ) is rolled to reduce the wall thickness.
  • a part of the hollow shell 2 located at a flange part (a portion where each grooved-roll 4 and the hollow shell 2 do not make contact) is pulled and elongated in the hollow shell axis direction based on the deformation of the part of the hollow shell 2 located at the groove bottom portion in the hollow shell axis direction that results from rolling.
  • the part of the hollow shell 2 located at the flange part receives no internal surface pressure and substantially no external surface pressure, and thus close to uniaxial tension, receiving only tensile force in the hollow shell axis direction. Therefore, the part of the hollow shell 2 located at the flange part easily encounters what is called a necking phenomenon, which refers to a partial reduction in wall thickness. If this necking phenomenon occurs dramatically, a hollow shell that is being elongated will break into generate holes.
  • the roll grooves of at least the first stand and the second stand are arranged so as to satisfy the following formulas (1) to (4).
  • a is a ratio of S/R 1 between a groove bottom curvature radius R 1 of each grooved-roll and a displacement-offset-amount S between a groove bottom curvature center and a mill center
  • b is ellipticity.
  • the groove bottom curvature radius R 1 of each grooved-roll and the displacement-offset-amount S between the groove bottom curvature center and the mill center are shown in FIG. 1 .
  • the ellipticity is represented by C/(R 1 ⁇ S) using the curvature radius R 1 , the displacement-offset-amount S between the groove bottom curvature center and a mill center O, and a longer radius C of the hollow shell are shown in FIG. 1 .
  • FIG. 2 is a figure showing the relationship between: the ratio S/R 1 between the groove bottom curvature radius R 1 of the grooved-roll and the displacement-offset-amount S between the groove bottom curvature center and the mill center, and the ellipticity in the mandrel mill of the present invention. It is noted that the relationship shown in the figure is regarding the first stand.
  • the hollow shell that is being elongated turns into an under-filled state relative to the grooved-roll.
  • the term “under-filled” means such a state that the outer circumferential length of the hollow shell being elongated does not increase sufficiently and thus is excessively small relative to the groove circumferential length (outer circumferential length of a projected groove profile). In the under-filled state, drawing-out failure of the bar (striping failure) or hole occurrence due to necking arises even though the ellipticity is large.
  • the hollow shell that is being elongated turns into an over-filled state relative to the grooved-roll.
  • the term “over-filled” means such a state that the outer circumferential length of the hollow shell being elongated increases excessively, resulting in protrusion from the grooved flange. In the over-filled state, the hollow shell protrudes from the grooved flange and a burning flaw occurs on the surface of the hollow shell.
  • the grooved-rolls of only at least the first stand and the second stand may be arranged so as to satisfy the conditions represented by the foregoing formulas (1) to (4). This is because the rolling reduction rate in the first stand and the second stand is generally larger than that in the other stands during mandrel mill rolling, and the influence that the groove shapes of the first and second stands have on rolling is significantly larger than the influence of the groove shapes of the third and later stands.
  • the hollow shell is rolled with a good balance between offset and ellipticity, and thus it is possible to suppress hole occurrence and flaw generation in an elongated seamless pipe. Therefore, a flaw such as necking can be suppressed even in the case of rolling a thin wall pipe and a high alloy steel pipe, which are easily subject to flaws.
  • FIG. 1 is a schematic diagram showing a positional relationship between a grooved-roll, a hollow shell, and a mandrel bar in a mandrel mill of the present invention.
  • FIG. 2 is a figure showing a relationship between: the ratio S/R 1 between a groove bottom curvature radius R 1 of a grooved-roll and a displacement-offset-amount S between a groove bottom curvature center and the mill center, and ellipticity in the mandrel of the present invention.
  • FIG. 3 is a schematic diagram showing an entire configuration of the mandrel mill.
  • FIG. 4 is a schematic diagram showing a rolling state of a seamless pipe on the mandrel mill, with (a) to (f) respectively showing a rolling state of the seamless pipe at the first to sixth stands of the mandrel mill.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
US12/312,423 2006-11-09 2007-10-24 Mandrel mill, operating method of the same and production method of seamless pipe Abandoned US20100064753A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2006303776A JP2008119706A (ja) 2006-11-09 2006-11-09 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
JP2006303776 2006-11-09
PCT/JP2007/070732 WO2008056540A1 (en) 2006-11-09 2007-10-24 Mandrel mill, its operating method, and seamless pipe manufacturing method

Publications (1)

Publication Number Publication Date
US20100064753A1 true US20100064753A1 (en) 2010-03-18

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US12/312,423 Abandoned US20100064753A1 (en) 2006-11-09 2007-10-24 Mandrel mill, operating method of the same and production method of seamless pipe
US12/563,229 Abandoned US20100132425A1 (en) 2006-11-09 2009-09-21 Mandrel mill, operating method of the same and production method of seamless pipe

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US12/563,229 Abandoned US20100132425A1 (en) 2006-11-09 2009-09-21 Mandrel mill, operating method of the same and production method of seamless pipe

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US (2) US20100064753A1 (pt)
EP (1) EP2085158A4 (pt)
JP (1) JP2008119706A (pt)
CN (1) CN101534969A (pt)
BR (1) BRPI0718203A2 (pt)
WO (1) WO2008056540A1 (pt)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110167973A1 (en) * 2010-01-12 2011-07-14 Wadsworth Lewis W Apparatus and Method for Cutting Tubular Members
US20130333433A1 (en) * 2010-11-16 2013-12-19 V & M Deutschland Gmbh Method for producing seamless hot-rolled pipes in continuous pipe rolling mills
CN109909297A (zh) * 2019-02-28 2019-06-21 西安建筑科技大学 一种大尺寸高温合金棒材的反锥螺线辊超细晶轧制方法
US20220241889A1 (en) * 2020-01-23 2022-08-04 Gachon University Of Industry-Academic Cooperation Foundation Method for manufacturing multi-layered nuclear fuel cladding pipe

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006031564A1 (de) * 2006-07-07 2008-01-10 Gesenkschmiede Schneider Gmbh Verfahren zur Herstellung eines rotationssymmetrischen Teils, insbesondere Welle
WO2011039942A1 (ja) * 2009-09-29 2011-04-07 住友金属工業株式会社 多ロールマンドレルミルおよび継目無管の製造方法
JP4883431B1 (ja) * 2010-07-07 2012-02-22 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
CN102371362B (zh) * 2010-08-25 2013-08-28 中国有色（沈阳）冶金机械有限公司 一种重型空心辊道静动平衡的加工方法
CN104785525B (zh) * 2015-04-07 2017-03-01 浙江嘉翔精密机械技术有限公司 一种提高核电蒸汽发生器换热管性能的方法
DE102018207908A1 (de) * 2018-05-18 2019-11-21 Sms Group Gmbh Streckreduzierungswalzwerk mit verbesserter Durchmesser- und Wanddickentoleranz

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2582705B2 (ja) 1991-06-21 1997-02-19 川崎製鉄株式会社 マンドレルミル
JPH07102369B2 (ja) 1991-08-22 1995-11-08 川崎製鉄株式会社 マンドレルミル
JP2985719B2 (ja) * 1995-04-04 1999-12-06 住友金属工業株式会社 マンドレルミル
JP2001113306A (ja) 1999-10-18 2001-04-24 Sumitomo Metal Ind Ltd 高合金継目無鋼管の製造方法およびそれに用いる圧延用孔型

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110167973A1 (en) * 2010-01-12 2011-07-14 Wadsworth Lewis W Apparatus and Method for Cutting Tubular Members
US9016178B2 (en) * 2010-01-12 2015-04-28 Lewis W. Wadsworth Apparatus and method for cutting tubular members
US9950472B2 (en) 2010-01-12 2018-04-24 Lewis W. Wadsworth Apparatus and method for cutting tubular members
US20130333433A1 (en) * 2010-11-16 2013-12-19 V & M Deutschland Gmbh Method for producing seamless hot-rolled pipes in continuous pipe rolling mills
US9381554B2 (en) * 2010-11-16 2016-07-05 Vallourec Deutschland Gmbh Method for producing seamless hot-rolled pipes in continuous pipe rolling mills
CN109909297A (zh) * 2019-02-28 2019-06-21 西安建筑科技大学 一种大尺寸高温合金棒材的反锥螺线辊超细晶轧制方法
US20220241889A1 (en) * 2020-01-23 2022-08-04 Gachon University Of Industry-Academic Cooperation Foundation Method for manufacturing multi-layered nuclear fuel cladding pipe
US12068083B2 (en) * 2020-01-23 2024-08-20 Gachon University Of Industry—Academic Cooperation Foundation Method for manufacturing multi-layered nuclear fuel cladding pipe

Also Published As

Publication number Publication date
EP2085158A1 (en) 2009-08-05
US20100132425A1 (en) 2010-06-03
CN101534969A (zh) 2009-09-16
EP2085158A4 (en) 2012-08-01
BRPI0718203A2 (pt) 2015-09-22
WO2008056540A1 (en) 2008-05-15
JP2008119706A (ja) 2008-05-29

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Owner name: SUMITOMO METAL INDUSTRIES, LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SASAKI, KENICHI;REEL/FRAME:025158/0392

Effective date: 20090512

STCB Information on status: application discontinuation

Free format text: EXPRESSLY ABANDONED -- DURING EXAMINATION