US3874211A - Method of controlling the wall thickness within a tube elongater by utilizing a screw down control - Google Patents

Method of controlling the wall thickness within a tube elongater by utilizing a screw down control Download PDF

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Publication number
US3874211A
US3874211A US435509A US43550974A US3874211A US 3874211 A US3874211 A US 3874211A US 435509 A US435509 A US 435509A US 43550974 A US43550974 A US 43550974A US 3874211 A US3874211 A US 3874211A
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US
United States
Prior art keywords
tube
screw down
elongater
mill
wall thickness
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.)
Expired - Lifetime
Application number
US435509A
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English (en)
Inventor
Chihiro Hayashi
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
Sumitomo Metal Industries Ltd
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
Priority to JP48025427A priority Critical patent/JPS5143825B2/ja
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Priority to US435509A priority patent/US3874211A/en
Priority to BE140091A priority patent/BE810061A/fr
Priority to FR7404635A priority patent/FR2219808B1/fr
Priority to GB744674A priority patent/GB1442492A/en
Priority to DE2409870A priority patent/DE2409870A1/de
Application granted granted Critical
Publication of US3874211A publication Critical patent/US3874211A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/16—Control of thickness, width, diameter or other transverse dimensions
    • B21B37/24—Automatic variation of thickness according to a predetermined programme
    • 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
    • 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
    • B21B17/12—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 in a discontinuous process, e.g. plug-rolling 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

Definitions

  • ABSTRACT This invention relates to a method of controlling the 52 us. 01 72/208 72/19 72/240 Wall thickness of tubes- A Special depressing mecha- 7203i nism is provided on the specific stands of a tube elon- 51 1111. c1 B2lb 17/04, B2l b 37/14 gater a Step Prior to a reducing that, by [58] Field of Search U 72/240 234 8 19 208 opening and tightening control. of this mechanism, the 72/209 54 reduction of the yield by the phenomenon of the ends thickening of a tube in the reducing mill may be pre- [56] References Cited vented.
  • the response to the depression may be quick and thus the efficiency of the production may be re- UNITED STATES PATENTS markably improved 2,209,968 8/1940 Gould et al. 72/209 X 2,767,603 10/1956 Rendcl 72/15 x 4 Claims, 9 Drawing Figures HTENTED W75 3.874.211
  • This invention relates to a continuous elongation method in the case of producing seamless tubes and more particularly to a method of wall thickness control in a tube elongater to provide a uniform wall thickness distribution in the lengthwise direction of a finished product through both the tube elongator and the reducing mill following it.
  • a piercing mill Mannesman piercer
  • tube elongater mandrel mill
  • reducing mill shtretch reducer
  • a round billet having come out ofa heating furnace is first bored with the piercing mill, the thus rolled hollow piece is short and thick, therefore it is reduced in wall thickness and extended in length with the next tube elongater so as to be shaped into a mother tube to be reduced.
  • a reducing mill is used to determine its outside diameter or to reduce the outside diameter to a smaller size.
  • This invention is to control the screw down of the rolls in the intermediate elongating step in order to obtain a uniform wall thickness distribution in the lengthwise direction of the finished tube in the final reducing step among the above mentioned tube making steps.
  • Such a mill is formed usually of 8 to 24 stands' and greatly reduces the outside diameter of the mother tube to make a small diameter tube.
  • the wall thickness increases at a rate corresponding to about one half the outside diameter reduction rate. Therefore, a considerably large tension (reaching about 85 percent of the resistance to deformation in the extreme case) is given between the respective stands during the rolling so that the wall thickness may be reduced
  • the rolls of each stand are controlled individually with a single DC. motor or one electric motor together with a differential gear and hydraulic motor called a Thoma axial piston type pump in each stand.
  • the object of this invention is to provide a controlling method of cancelling the phenomenon of the ends 5 thickening of a tube in a reducing mill by tapering and reducing the wall thickness near each end of the tube in advance in an elongation step prior to a reducing step in order to prevent such phenomenon of the ends thickening of the tube and to greatly improve the yield.
  • this invention relates to a method of thinning the ends of a tube in a tube elongater in order to cancel the phenomenon of the ends thickening of a tube in a reducing mill.
  • a mandrel mill as an example of the tube elongater
  • this invention shall be explained more particularly with reference to a continuous rolling step of a Mannesman piercer (piercing mill), mandrel mill (tube elongater) and stretch reducing mill (reducing mill).
  • the mandrel mill is a rolling mill for elongation of a hollow piece pierced with the Mannesman piercer as inserted with a mandrel bar and is an X-mill formed usually of eight stands inclined by 45 to the horizontal and alternately varied by in the arrangement.
  • the rolls of each stand are driven independently by a DC. motor.
  • the tube is brought into close contact with the mandrel bar with the first one or two stands, is reduced in the wall thickness with the next five stands and is made truly circular in the cross-section with the final stand and, at the same time, a uniform clearance is made between the tube and mandrel bar so that the bar may be easy to strip out.
  • the reduction of the crosssection finishes mostly between the first stand and the sixth stand. The reduction can not be given even with the seventh stand but the seventh stand should be understood to be a sizing stand for making an oval and it is required to make the tube truly circular in crosssection with the eighth stand.
  • FIG. 1 A-E is a schematic view showing an example of steps of seamless tube making
  • FIG. 2 is a view showing the wall thickness distribution in the lengthwise direction of a finished product produced in ordinary tube making steps
  • FIG. 3 is an'explanatory View showing the essential point of the control of this invention with a depressed area reduction rate
  • FIG. 4 is an exemplary view showing the wall thickness distribution in the lengthwise direction of a finished product produced by the method of the wall thickness control of this invention
  • FIG. 5 is a view showing an apparatus of this invention.
  • A is a rotary bed type heating furnace
  • B is a Mannesman piercer
  • C is a mandrel mill
  • D is a walking beam type reheating furnace
  • E is a stretch reducing mill.
  • I is a round billet.
  • 2 is a hollow piece
  • 3 is a mandrel bar
  • 4 is a mother tube to be reduced.
  • FIG. 2 An example of the wall thickness distribution in the lengthwise direction of a tube to be produced in the above tube making steps is shown in FIG. 2.
  • the mother tube entering the reducing mill E in this case is of an outside diameter of 108mm, wall thickness of 5.5mm. and length of 15,700mm. and the finished product tube is of an outside diameter of 27.2mm, wall thickness of 4.5mm. and elongated length of 85,800mm.
  • the tube becomes so remarkably thicker than in the middle part that it can not be used at all as a product and therefore part of the ends of the tube are cut off to remarkably reduce the yield of production.
  • this invention is to control the wall thickness to make thinner the tube ends in the mandrel mill C in the step prior to the reducing mill E to prevent the remarkable reduction of the yield caused by such phenomenon of the thickening.
  • the screw down as the tube enters and leaves the mill is controlled by using the specific fifth stand and sixth stand. That is to say, the roll gaps of the fifth stand and sixth stand are closed inadvance by a fixed screw down.
  • the depressing screws of the fifth stand and sixth stand are elevated at a rising velocity given a fixed acceleration until a fixed roll gap is reached to open the clearance.
  • the depressing screws of the fifth stand and sixth stand are lowered and tightened at a lowering velocity having an acceleration until a fixed roll gap is made to close the clearance.
  • the wall thickness control to make the tube ends thinner is by the screw down control.
  • the control of the roll r.p.m. of the fifth and sixth stands can be simultaneously added. For this purpose, it is easy to particularly add the control of the roll r.p.m. of all the stands as the tube enters and leaves the mill.
  • FIG. 4 An example of the wall thickness distribution in the lengthwise direction after the reducing step ofa mother tube having had the wall thickness thus controlled at both entering of the front end and leaving of the rear end of the tube in the step of the mandrel mill C is shown in FIG. 4.
  • the dimensions of the mother tube entering the reducing mill E are the same as in the case of FIG. 2 and the dimensions of the product are also exactly the same except that the elongated length is slightly different.
  • the phenomenon of the tube ends thickening in the reducing mill E is substantially perfectly cancelled with the ends thinning control ofthe tube thereby providing uniform wall thickness distribution in the lengthwise direction.
  • the sixth and seventh stands may be made screw down controlling stands, or the screw down may be made with only one specific stand.
  • the roll gaps of the fifth stand and sixth stand is closed in advance by a fixed screw down and, when a fixed time has passed from the time when the front end of the tube enters the fourth stand, the roll gaps of the fifth stand and sixth stand is opened with a fixed acceleration until a fixed roll gap is reached and, when a fixed time has passed from the time when the rear end of the tube leaves the fourth stand, the roll gaps of the fifth stand and sixth stand is closed with a fixed acceleration until a fixed roll gaps is reached.
  • the control of the wall thickness to make the tube ends thinner is made by controlling the screw down.
  • a hollow piece pierced with a Mannesman piercer as inserted with a mandrel bar of a perfect rigid body is elongated and rolled with caliber rolls consisting of about eight stands. Therefore, the pass line must always coincide with the center axis of the mandrel bar. Not only in the stead state in which the tube is engaged in all the stands but also in the transient state in which the tube is entering or leaving them at the rear ends, the rolling must proceed with the pass line unchanged.
  • FIG. 5 An example of hydraulic screw down controlling mechanism relating to this invention is shown in FIG. 5. It shall be explained in the following. This example is an improved development of the hydraulic screw down mill system of I company developed as a strip thickness controlling system of a strip mill. However, a system of H Company or a system developed jointly by the applicant of this invention and M Company may be also used. The principle mechanism of the hydraulic screw down in not to be claimed here.
  • FIG. 5 illustrating a housing 5 for one side ofa roll I stand of the mandrel mill
  • 6 is an upper roll
  • 6" is a lower roll
  • 7' and 7" are roll chocks which are incorporated in the housing so as to be able to control the roll gap as opposed to each other above and below the pass line as a center. That is to say, the upper surface of the roll chock 7' and the lower surface of the roll chock 7" bearing respectively the rotated and driven roll 6 and 6" are connected respectively with the heads of hydraulically operated cylinder 8 and 8" so as to be slidable up and down within the housing.
  • a main load cell 12 is fitted between the upper roll chock 7 and its hydraulic push-up cylinder 8'.
  • the compression bars 11' and 11 are fitted with bar load cells 13' and 13" for the respective adjusting bars.
  • the output signals of these load cells are made inputs respectively of an upper calculation controlling device and lower calculation controlling device 15" through a calculator 14' for the cells 12 and 13' and a summing amplifier 14" for the cells 12 and 13".
  • roll controlling servo valves 16' and 16" operate respectively the upper cylinder 8' and lower cylinder 8" connected with an oil pressure generating device 17 by the instructions of calculation controlling devices 15' and 15" and control the screw down of the upper roll 6 and lower roll 6" as set symmetrically above and below the pass line.
  • the calculation controlling device controls the loads P and P by comparing the outputs of the main load cell 12 and bar load cell 13" and varies the push-up forces of the oil pressure cylinders 8' and 8" by actuating the servo valves 16 and 16 so as to keep the ratio at a predetermined fixed ratio.
  • the housing on one side is shown in FIG. 5.
  • the housing on the other side is provided also with the same devices. As described later, these controlling devices are connected through an electric circuit so as to operate exactly the same on the right and left hous ings.
  • the calculating devices 15' and 15" will work so that the push-up force P, that is, the roll position may be automatically corrected until the balance is obtained.
  • the roll gap will become constant irrespective of the rolling load, the rolled thickness and outside diameter will be constant irrespective of the rolling conditions and the roll gap will be as set.
  • the thickness adjustment in this type of hydraulic screw down mill can be made by the following two methods.
  • the first of them is to move the compression bars 11' and 11" up and down with the screws 9' and 9" and adjust the lengths projecting out of the roll chocks 7 and 7" oftheir tips 10' and 10".
  • the second method is to give an electric voltage signal K X proportional to a screw down adjusting amount X to the calculator.
  • the screw down by the first method is used only for the ordinary setting.
  • the ends thinning control of the tube during the rolling is made by the second method. In the latter, the mechanical movement within the rolling mill is only to let in and out the oil pressure oil, all the others are to send out and receive electric signals and therefore a very high speed screw down response is obtained.
  • K is a spring constant of the adjusting bar.
  • a method for controlling the wall thickness of a tube in a tube elongater with the utilization of a hydraulilc screw down control mechanism comprising the steps of: passing the tube through a tube elongator after the tube has passed through a piercing mill and prior to the tube passing through a reducing mill; passing the tube through the hydraulic screw down control mechanism arranged within the elongator, such mechanism including upper and lower caliber rolls which may be screwed down and opened symmetrically about a pass line as the tube enters and leaves the elongater; controlling the movement of the upper and lower caliber rolls as the tube passes through the mechanism such that the caliber rolls are temporarily screwed down as the ends of the tube pass through the mechanism and are open when the middle of the tube passes through the mechanism, whereby the ends of the tubes are made thinner within the elongater prior to the tube entering the reducing mill.
  • a method according to claim 1, wherein the step of thinning the ends of the tube is accomplished by moving compression bars positioned above the upper and lower caliber rolls within the hydraulic screw down mechanism in an up and down direction with the utilization of screws provided in the housing of the tube elongater so as to adjust the portions of the rolls projecting out of their respective roll chocks about the pass line.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Metal Rolling (AREA)
US435509A 1973-03-02 1974-01-22 Method of controlling the wall thickness within a tube elongater by utilizing a screw down control Expired - Lifetime US3874211A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
JP48025427A JPS5143825B2 (fr) 1973-03-02 1973-03-02
US435509A US3874211A (en) 1973-03-02 1974-01-22 Method of controlling the wall thickness within a tube elongater by utilizing a screw down control
BE140091A BE810061A (fr) 1973-03-02 1974-01-23 Procede pour regler l'epaisseur de paroi dans un laminoir elongatrur pour tubes
FR7404635A FR2219808B1 (fr) 1973-03-02 1974-02-12
GB744674A GB1442492A (en) 1973-03-02 1974-02-19 Method of and apparatus for the production of seamless tubes of uniform wall thickness
DE2409870A DE2409870A1 (de) 1973-03-02 1974-03-01 Verfahren zur dickensteuerung beim rohrwalzen

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP48025427A JPS5143825B2 (fr) 1973-03-02 1973-03-02
US435509A US3874211A (en) 1973-03-02 1974-01-22 Method of controlling the wall thickness within a tube elongater by utilizing a screw down control

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Publication Number Publication Date
US3874211A true US3874211A (en) 1975-04-01

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US435509A Expired - Lifetime US3874211A (en) 1973-03-02 1974-01-22 Method of controlling the wall thickness within a tube elongater by utilizing a screw down control

Country Status (6)

Country Link
US (1) US3874211A (fr)
JP (1) JPS5143825B2 (fr)
BE (1) BE810061A (fr)
DE (1) DE2409870A1 (fr)
FR (1) FR2219808B1 (fr)
GB (1) GB1442492A (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2425283A1 (fr) * 1978-05-10 1979-12-07 Mannesmann Ag Procede et laminoir a tubes pour la fabrication de tubes par poussee en partant d'une ebauche tubulaire
US4323971A (en) * 1979-11-23 1982-04-06 Kocks Technik Gmbh & Co. Adjustment means for stretch reduction rolling mills
US6006789A (en) * 1995-08-25 1999-12-28 Kawasaki Steel Corporation Method of preparing a steel pipe, an apparatus thereof and a steel pipe
US20090308125A1 (en) * 2006-10-16 2009-12-17 Akihito Yamane Mandrel mill and process for manufacturing a seamless pipe
CN102303051A (zh) * 2011-06-15 2012-01-04 天津商业大学 使用七机架连轧机轧制无缝钢管的管形控制方法
US20130205858A1 (en) * 2011-09-12 2013-08-15 Holger Schulz Device for undulating a pipe consisting of metal
US20150121982A1 (en) * 2012-07-24 2015-05-07 Nippon Steel & Sumitomo Metal Corporation Manufacturing method of seamless metal pipe, mandrel mill, and auxiliary tool

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005044777A1 (de) * 2005-09-20 2007-03-29 Sms Meer Gmbh Verfahren und Walzwerk zur Herstellung eines nahtlosen Rohres

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2209968A (en) * 1938-05-02 1940-08-06 Nat Tube Co Manufacture of bessemer steel seamless tubes
US2767603A (en) * 1952-08-06 1956-10-23 United States Steel Corp Semiautomatic screw-down control for rolling mills
US2780118A (en) * 1953-02-05 1957-02-05 United States Steel Corp Apparatus for rolling tubes
US3369383A (en) * 1965-07-16 1968-02-20 Gen Dynamics Corp Rolling mill system
US3490256A (en) * 1966-02-10 1970-01-20 United Eng Foundry Co Control for obtaining constant gauge in a rolling mill
US3645121A (en) * 1968-07-05 1972-02-29 Mannesmann Roehren Werke Ag Method for rolling tubular material stock in a stretch reducing mill

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3492845A (en) * 1966-12-30 1970-02-03 Shibaura Kyodo Kogyo Kk Rolling mill control system
FR1515654A (fr) * 1967-03-21 1968-03-01 Kocks Gmbh Friedrich Procédé de réduction de tubes

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2209968A (en) * 1938-05-02 1940-08-06 Nat Tube Co Manufacture of bessemer steel seamless tubes
US2767603A (en) * 1952-08-06 1956-10-23 United States Steel Corp Semiautomatic screw-down control for rolling mills
US2780118A (en) * 1953-02-05 1957-02-05 United States Steel Corp Apparatus for rolling tubes
US3369383A (en) * 1965-07-16 1968-02-20 Gen Dynamics Corp Rolling mill system
US3490256A (en) * 1966-02-10 1970-01-20 United Eng Foundry Co Control for obtaining constant gauge in a rolling mill
US3645121A (en) * 1968-07-05 1972-02-29 Mannesmann Roehren Werke Ag Method for rolling tubular material stock in a stretch reducing mill

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2425283A1 (fr) * 1978-05-10 1979-12-07 Mannesmann Ag Procede et laminoir a tubes pour la fabrication de tubes par poussee en partant d'une ebauche tubulaire
US4275578A (en) * 1978-05-10 1981-06-30 Wean United, Inc. Apparatus for manufacturing tubes by continuous hot rolling
US4323971A (en) * 1979-11-23 1982-04-06 Kocks Technik Gmbh & Co. Adjustment means for stretch reduction rolling mills
US6006789A (en) * 1995-08-25 1999-12-28 Kawasaki Steel Corporation Method of preparing a steel pipe, an apparatus thereof and a steel pipe
US20090308125A1 (en) * 2006-10-16 2009-12-17 Akihito Yamane Mandrel mill and process for manufacturing a seamless pipe
US8122749B2 (en) * 2006-10-16 2012-02-28 Sumitomo Metal Industries, Ltd. Mandrel mill and process for manufacturing a seamless pipe
CN102303051A (zh) * 2011-06-15 2012-01-04 天津商业大学 使用七机架连轧机轧制无缝钢管的管形控制方法
CN102303051B (zh) * 2011-06-15 2013-04-03 天津商业大学 使用七机架连轧机轧制无缝钢管的管形控制方法
US20130205858A1 (en) * 2011-09-12 2013-08-15 Holger Schulz Device for undulating a pipe consisting of metal
US9283607B2 (en) * 2011-09-12 2016-03-15 Nexans Device for corrugating a pipe consisting of metal
US20150121982A1 (en) * 2012-07-24 2015-05-07 Nippon Steel & Sumitomo Metal Corporation Manufacturing method of seamless metal pipe, mandrel mill, and auxiliary tool
US9884355B2 (en) * 2012-07-24 2018-02-06 Nippon Steel & Sumitomo Metal Corporation Manufacturing method of seamless metal pipe, mandrel mill, and auxiliary tool

Also Published As

Publication number Publication date
GB1442492A (en) 1976-07-14
JPS49113752A (fr) 1974-10-30
JPS5143825B2 (fr) 1976-11-25
BE810061A (fr) 1974-05-16
FR2219808A1 (fr) 1974-09-27
DE2409870A1 (de) 1974-09-12
FR2219808B1 (fr) 1977-09-30

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