JPH0924408A - Method for controlling elongation rolling of steel tube - Google Patents
Method for controlling elongation rolling of steel tubeInfo
- Publication number
- JPH0924408A JPH0924408A JP7173479A JP17347995A JPH0924408A JP H0924408 A JPH0924408 A JP H0924408A JP 7173479 A JP7173479 A JP 7173479A JP 17347995 A JP17347995 A JP 17347995A JP H0924408 A JPH0924408 A JP H0924408A
- Authority
- JP
- Japan
- Prior art keywords
- rolling
- pipe
- roll
- mill
- tube
- 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.)
- Granted
Links
Landscapes
- Control Of Metal Rolling (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、中空素管から延伸
圧延機及び絞り圧延機を経て継目無し鋼管を製造する際
に、延伸圧延機での管先後端部での素管形状不良を防止
すると共に、絞り圧延機における先後端厚肉化を抑制す
る鋼管の延伸圧延制御方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when producing a seamless steel pipe from a hollow shell through a drawing and rolling machine and a drawing and rolling machine, prevents a defective shape of the tube at the tip and rear ends of the drawing and rolling machine. In addition, the present invention relates to a method for controlling the stretching and rolling of a steel pipe that suppresses the thickening of the front and rear ends in a drawing rolling mill.
【0002】[0002]
【従来の技術】一般に、継目無し鋼管の製造には、マン
ドレルミル方式、プラグミル方式の圧延方法、あるい
は、ユージンセジュルネ方式、エアハルトプッシュベン
チ方式等の熱間押出方法が用いられているが、比較的小
径サイズでは、生産性、寸法精度のより優れたマンドレ
ルミル圧延方式が多い。2. Description of the Related Art Generally, a mandrel mill method, a plug mill method, or a Eugene Sejournet method, an Erhart push bench method, or another hot extrusion method is used to manufacture a seamless steel pipe. For small diameter size, there are many mandrel mill rolling methods that are more excellent in productivity and dimensional accuracy.
【0003】まず、図4を参照してマンドレルミル圧延
方式による一般的な継目無し鋼管製造工程を説明する。First, a general seamless steel pipe manufacturing process by the mandrel mill rolling method will be described with reference to FIG.
【0004】製造設備は、加熱炉1、穿孔圧延機(マン
ネスマンピアサー)2、延伸圧延機(マンドレルミル)
3、再加熱炉4及び絞り圧延機(ストレッチレデュー
サ)5から構成されている。加熱炉1、穿孔圧延機2の
代わりに中空管製造用連続鋳造機6が用いられることも
ある。The manufacturing equipment includes a heating furnace 1, a piercing and rolling mill (Mannesmann piercer) 2, and a drawing and rolling mill (mandrel mill).
3, a reheating furnace 4 and a reduction rolling machine (stretch reducer) 5. A continuous casting machine 6 for hollow tube production may be used instead of the heating furnace 1 and the piercing and rolling machine 2.
【0005】加熱炉1において、所定温度(一般に11
00℃〜1300℃)に加熱された素材ビレット7は、
穿孔圧延機2のピアサーロール8の間でプラグ9により
穿孔圧延され中空素管7Aとなる。In the heating furnace 1, a predetermined temperature (generally 11
The material billet 7 heated to 00 ° C to 1300 ° C is
A hollow shell 7A is obtained by piercing and rolling with a plug 9 between the piercer rolls 8 of the piercing and rolling machine 2.
【0006】次に、中空素管7Aは、延伸圧延機3にお
いて表面に熱間圧延用潤滑剤を塗布したマンドレルバー
10を挿入した状態で、複数段のマンドレルミルロール
(孔型ロール)11の間で減肉圧延され、肉厚が低減さ
れると共に、その長さが延ばされて、レデューサ素管1
2とされる。Next, in the hollow shell 7A, a mandrel bar 10 having a surface coated with a lubricant for hot rolling is inserted in the drawing and rolling mill 3, and a plurality of mandrel mill rolls (hole type rolls) 11 are provided. The thickness of the reducer element pipe 1
It is set to 2.
【0007】このレデューサ素管12は再加熱炉4にお
いて再加熱された後に、絞り圧延機5において絞り圧延
することによって、その外径を定め、又は外径を絞って
小径とする。The reducer element tube 12 is reheated in the reheating furnace 4 and then subjected to drawing rolling in the drawing rolling mill 5 to determine its outer diameter or to reduce the outer diameter to a small diameter.
【0008】この最後の絞り圧延機5においては、スタ
ンド間張力を付加して長手方向へのメタルフローを制御
するものであるが、レデューサ素管12の先後端部はス
タンド間張力を付加できないので非定常な圧延となり、
該先後端部の肉厚は、例えば図5に示されるように、ス
タンド間張力が付加される定常部(中間部)に比較して
厚くなってしまう。In this final drawing rolling mill 5, tension between stands is applied to control the metal flow in the longitudinal direction, but tension between stands cannot be applied to the front and rear ends of the reducer element tube 12. Unsteady rolling,
For example, as shown in FIG. 5, the wall thickness of the front and rear end portions becomes thicker than that of a steady portion (intermediate portion) to which tension between stands is applied.
【0009】この先後端部の肉厚が、製品に対して要求
される肉厚公差を外れる場合は、クロップとして切断さ
れ、これが製品の歩留りを低下させる大きな原因となっ
ていた。If the wall thickness at the front and rear ends is out of the wall thickness tolerance required for the product, it is cut as a crop, which is a major cause of lowering the product yield.
【0010】この対策としては、絞り圧延前の延伸圧延
機で、図6に示されるように、レデューサ素管12の先
後端部の肉厚が、定常部に比較して薄く減肉されるよう
な圧延方法が提案されている。As a measure against this, in the drawing rolling machine before the reduction rolling, as shown in FIG. 6, the wall thickness of the front and rear end portions of the reducer element tube 12 is thinned as compared with the steady portion. Various rolling methods have been proposed.
【0011】例えば特公昭51−43825号公報に開
示されるマンドレルミルにおける油圧圧下制御方法にお
いては、マンドレルミルの特定の2スタンドにおいて、
従来のモータによるロール圧下装置に比較して応答の速
い油圧圧下機構を設け、管先後端の肉厚が、次工程の絞
り圧延機で生じる厚肉化を相殺する如く油圧圧下機構で
圧下制御して薄肉にするようにしている。[0011] For example, in the hydraulic pressure reduction control method for a mandrel mill disclosed in Japanese Patent Publication No. 51-43825, in two specific stands of the mandrel mill,
A hydraulic pressure reduction mechanism, which has a quick response compared to the conventional roll reduction device using a motor, is installed, and the hydraulic pressure reduction mechanism controls the thickness of the pipe tip rear end so as to offset the thickening that occurs in the drawing and rolling mill in the next process. I try to make it thin.
【0012】しかしながら、上記特公昭51−4382
5号公報の油圧圧下制御方法では、延伸圧延機における
中空素管先後端での孔型ロールの圧下に伴い、孔型ロー
ルフランジ部間のギャップへのバルジングと称される材
料の噛み出しが大きくなり、レデューサ素管の形状不良
を招くという問題点がある。このバルジング部分が大き
くなると、絞り圧延機でのロール面圧が増加して、材料
が焼き付いて表面疵の要因を発生させたり、メタルフロ
ー欠陥を発生させるという問題点がある。However, the above Japanese Examined Patent Publication No. 51-4382.
In the hydraulic reduction control method disclosed in Japanese Patent Laid-Open No. 5 publication, the material called out bulging into the gap between the flanges of the hole-shaped rolls is largely caused by the reduction of the hole-shaped rolls at the front and rear ends of the hollow shell in the drawing rolling mill. Therefore, there is a problem in that the reducer element tube is defective in shape. When this bulging portion becomes large, there is a problem that the roll surface pressure in the drawing rolling machine increases, causing the material to seize, causing a surface flaw, or causing a metal flow defect.
【0013】これに対して、例えば特公平3−7700
3号公報には、中空素管の両端部圧延時に孔型ロールの
間隙を減じると共に該中空素管に長手方向に付加的張力
を加えるようにロール回転数を制御して、バルジング変
形を抑制する管の連続延伸圧延方法が開示されている。On the other hand, for example, Japanese Patent Publication No. 3-7700
In Japanese Patent Publication No. 3, the bulging deformation is suppressed by reducing the gap between the hole-shaped rolls at the time of rolling both ends of the hollow shell and controlling the roll rotation speed so as to apply additional tension to the hollow shell in the longitudinal direction. A method for continuous drawing and rolling of tubes is disclosed.
【0014】[0014]
【発明が解決しようとする課題】しかしながら、上記特
公平3−77003号公報に開示された管の連続延伸圧
延方法では、孔型ロールを回転させるモータの応答性が
遅い場合、特に、ロール間隙を小さくして減肉量を大き
くすると、ロール回転数を制御するモータの応答遅れに
よって、中空素管の端部に、所望の長手方向の付加的張
力を加えることが不可能となる。However, in the tube continuous drawing and rolling method disclosed in the above Japanese Patent Publication No. 3-77003, when the responsiveness of the motor for rotating the hole-type roll is slow, especially the roll gap is reduced. When the wall thickness reduction amount is made small, the response delay of the motor controlling the roll rotation speed makes it impossible to apply a desired additional tension in the longitudinal direction to the end of the hollow shell.
【0015】このため、中空素管両端の薄肉化圧延部の
バルジング変形を完全に防止することができず、管の内
外表面疵、メタルフロー欠陥等の品質欠陥が生じてしま
うという問題点がある。Therefore, it is impossible to completely prevent the bulging deformation of the thinned and rolled portions at both ends of the hollow shell, and there arises a problem that quality defects such as inner and outer surface flaws of the pipe and metal flow defects occur. .
【0016】これに対して、モータの応答遅れを考慮し
て、予め過度の長手方向負荷的張力を加えるような圧下
制御をすると、管両端のバルジング変形は防止すること
ができるものの、管の内周長が過小になり、管がマンド
レルバーと密着して、圧延後に仕上圧延用素管(レデュ
ーサ素管)からマンドレルバーを引き抜くことができな
くなるストリッピングミスを発生させてしまうという問
題点が生じる。On the other hand, in consideration of the response delay of the motor, if the rolling-down control is performed in advance so as to apply an excessive load tension in the longitudinal direction, the bulging deformation at both ends of the pipe can be prevented, but the inside of the pipe can be prevented. There is a problem that the circumference becomes too small, the tube comes into close contact with the mandrel bar, and stripping error occurs that makes it impossible to pull out the mandrel bar from the finishing rolling stock tube (reducer stock tube) after rolling. .
【0017】この発明は上記問題点に鑑みてなされたも
のであって、延伸圧延の際の鋼管の先後端部を減肉する
薄肉化圧延を実施する場合において、ロール回転数を制
御するモータの応答性が遅い場合においても、被圧延素
管の管端部のバルジング変形及び被圧延素管とマンドレ
ルバーとの密着を防止し、管の内外表面疵、メタルフロ
ー欠陥等の品質欠陥、更にはストリッピングミスを低減
させ、歩留りを向上させることができる鋼管の延伸圧延
制御方法を提供することを目的とする。The present invention has been made in view of the above problems, and in the case of carrying out thinning rolling for thinning the front and rear ends of the steel pipe at the time of stretch rolling, a motor for controlling the rotation speed of the roll is used. Even when the response is slow, it prevents bulging deformation of the pipe end of the rolled stock pipe and close contact between the rolled stock pipe and the mandrel bar, and quality defects such as inner and outer surface flaws of the pipe, metal flow defects, etc. An object of the present invention is to provide a method for controlling the stretching and rolling of a steel pipe, which can reduce stripping mistakes and improve the yield.
【0018】[0018]
【課題を解決するための手段】この発明は、本発明者
が、研究を重ねた結果、孔型ロールのフランジ部での間
隙と、ロール孔型の溝からフランジ部に至る逃げ部の曲
率と、ロール孔型深さとの関係を一定条件にすることに
よって、被圧延素管の両管端部におけるバルジング変形
及び被圧延素管とマンドレルバーとの密着を防止できる
ことを見出したことによるものである。As a result of repeated studies by the inventor of the present invention, the present invention has revealed a gap in a flange portion of a hole-type roll and a curvature of a clearance portion from a roll-hole-type groove to a flange portion. The reason for this is that it is possible to prevent bulging deformation at both tube ends of the raw material pipe to be rolled and close contact between the raw material pipe to be rolled and the mandrel bar by keeping the relationship with the roll hole depth constant. .
【0019】本発明者は、まず、薄肉化圧延を行う被圧
延素管先後端部でバルジング変形及び被圧延素管とマン
ドレルバーとの密着を防止するための条件を見出した
が、この条件の圧延では薄肉化圧延を行わない被圧延素
管の長手方向中間部においてバルジング変形及びマンド
レルバーとの密着が発生する場合があることが判明し
た。The inventor first found a condition for preventing bulging deformation and adhesion between the rolled raw pipe and the mandrel bar at the front and rear ends of the rolled raw pipe to be thinned and rolled. It was found that in rolling, bulging deformation and close contact with the mandrel bar may occur in the longitudinal middle portion of the material tube to be rolled that is not subjected to thinning rolling.
【0020】そこで更に研究を重ねた結果、次のよう
な、被圧延素管の全長にわたってバルジング変形及びマ
ンドレルバーとの密着を防止することができる条件を見
出した。As a result of further studies, the following conditions have been found that can prevent bulging deformation and close contact with the mandrel bar over the entire length of the material tube to be rolled.
【0021】即ち、マンドレルバーを挿入した中空素管
を、孔型ロールをそれぞれに備えた複数のスタンドによ
って構成される連続延伸圧延機により延伸圧延を行う際
に、後工程の絞り圧延機における管先後端部の厚肉化を
抑制するために前記延伸圧延機で予め管の先後端部の肉
厚を減肉するように圧下位置を制御する管の延伸圧延制
御方法において、前記圧下位置制御を実施する延伸圧延
機のスタンドにおける孔型ロールの溝からフランジ部に
至る逃げ部の曲率をR3、溝底部からフランジ部までの
溝底深さをDKとしたとき、前記フランジ部のロール間
隙Gを、圧延先端から圧延後端の全長にかけて、 −0.67G/DK+0.4≦R3/DK≦−G/DK
+0.8 の範囲に制御することを特徴とする鋼管の延伸圧延制御
方法である。That is, when a hollow shell having a mandrel bar inserted therein is stretch-rolled by a continuous stretch-rolling machine composed of a plurality of stands each having a hole-type roll, the tube in a draw-rolling machine in a subsequent step is used. In the method for controlling the stretching and rolling of the pipe, which controls the rolling position to reduce the wall thickness of the front and rear ends of the pipe in advance in the stretching rolling machine in order to suppress the thickening of the front and rear ends, the rolling position control is performed. When the curvature of the relief portion from the groove of the hole-type roll in the stand of the stretch rolling mill to be performed to the flange portion is R3 and the groove bottom depth from the groove bottom portion to the flange portion is DK, the roll gap G of the flange portion is , -0.67G / DK + 0.4≤R3 / DK≤-G / DK from the rolling tip to the rolling trailing edge
This is a method for controlling the stretching and rolling of a steel pipe, which is characterized by controlling the range within +0.8.
【0022】即ち、図1に示されるように、バルジング
発生域とストリッピングミス発生域との間にそのどちら
もが発生しない最適範囲で鋼管の延伸圧延を行うので、
圧延後のマンドレルバーの引き抜き不良、バルジング疵
の発生等を解消することができる。That is, as shown in FIG. 1, since the steel pipe is stretch-rolled in the optimum range in which neither of the bulging occurrence region and the stripping error occurrence region occurs,
It is possible to eliminate defective drawing of the mandrel bar after rolling, occurrence of bulging defects, and the like.
【0023】[0023]
【発明の実施の形態】以下、図面に基づいて、本発明の
より具体的な実施の形態の例を詳細に説明する。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of a more specific embodiment of the present invention will be described in detail with reference to the drawings.
【0024】この実施の形態の例は、図2に示されるよ
うに、第1〜8スタンド20A〜20Hの複数段の孔型
ロールから構成される延伸圧延機20で、中空素管22
にマンドレルバー24を挿入して延伸圧延するとき、前
記第5スタンド20E及び第6スタンド20Fで中空素
管22の先後端の減肉を行う際に、次のような条件で、
制御装置30により孔型ロール26の圧下位置制御をす
るものである。As shown in FIG. 2, the example of this embodiment is a draw rolling machine 20 composed of a plurality of stages of hole type rolls of first to eighth stands 20A to 20H, and a hollow shell 22
When the mandrel bar 24 is inserted into and stretch-rolled, when thinning the front and rear ends of the hollow shell 22 with the fifth stand 20E and the sixth stand 20F, under the following conditions,
The control device 30 controls the rolling position of the hole type roll 26.
【0025】延伸圧延は、図3に示されるように、孔型
ロール26における孔型の溝26Aからフランジ部26
Bに至る逃げ部26Cの曲率R3、溝底部26Dからフ
ランジ部26Bまでの溝底深さDKとしたとき、フラン
ジ部26Bでのロール間隙Gを圧延先端から圧延後端の
全長にかけて、 −0.67G/DK+0.4≦R3DK≦−G/DK+0.8 …(1) なる条件の範囲に制御する。As shown in FIG. 3, the stretching rolling is carried out from the groove 26A of the groove in the hole roll 26 to the flange portion 26.
When the curvature R3 of the relief portion 26C reaching the B and the groove bottom depth DK from the groove bottom portion 26D to the flange portion 26B are set to be −0. 67 G / DK + 0.4 ≦ R3DK ≦ −G / DK + 0.8 (1) Control is performed within the range of the condition.
【0026】図3の符号R1は溝底部26Dの曲率半
径、R2は肩部26Eの曲率半径、B0 は包み角をそれ
ぞれ示す。Reference numeral R1 in FIG. 3 indicates the radius of curvature of the groove bottom portion 26D, R2 indicates the radius of curvature of the shoulder portion 26E, and B0 indicates the wrapping angle.
【0027】前記、第5及び第6スタンド20E、20
Fの出側にはバルジ幅測定装置32E、32Fをそれぞ
れ設け、該バルジ幅測定装置32E、32Fによりバル
ジ幅を測定するようにした。前記バルジ幅測定装置32
E、32Fは高温の材料を非接触で幅測定できる光学式
測定装置が望ましい。但し、バルジ幅測定装置は本発明
の延伸圧延制御の結果を確認するためのものであって、
本発明実施の必須要件ではないので、必ずしも設けなく
てよもよい。The fifth and sixth stands 20E, 20
Bulge width measuring devices 32E and 32F are provided on the output side of F, and the bulge width is measured by the bulge width measuring devices 32E and 32F. The bulge width measuring device 32
E and 32F are preferably optical measuring devices capable of non-contact width measurement of high temperature materials. However, the bulge width measuring device is for confirming the result of the stretching and rolling control of the present invention,
Since it is not an essential requirement for implementing the present invention, it is not always necessary to provide it.
【0028】前記第5及び第3スタンド20E、20F
では、それぞれ圧下位置制御に対する応答性に優れた油
圧圧下装置を用いて次のように圧延制御を実施する。The fifth and third stands 20E, 20F
Then, the rolling control is carried out as follows by using the hydraulic pressure reducing devices each having excellent responsiveness to the rolling position control.
【0029】ストレッチレデューサで仕上圧延された
仕上管の先後端部に形成される厚肉化の程度を予測又は
経験的に把握し、その厚肉部を相殺するような仕上圧
延用素管の先後端部の長手方向肉厚分布を理論的、又は
経験的に求め、この肉厚分布を目標値として、仕上圧
延用素管の長手方向中央部に比較して先後端部が薄肉と
なるように、孔型ロール26の圧下位置を制御する。Predicting or empirically grasping the degree of thickening formed at the front and rear ends of the finish pipe finish-rolled by the stretch reducer, and before and after the finish-rolling raw pipe that cancels the thick-walled portion. Calculate the wall thickness distribution in the longitudinal direction theoretically or empirically, and use this wall thickness distribution as a target value so that the front and rear ends are thinner than the central portion in the longitudinal direction of the finishing rolling pipe. The position of reduction of the hole type roll 26 is controlled.
【0030】更に具体的には、当初、第5及び第6スタ
ンド20E、20Fのロール間隔Gは、仕上圧延用素管
の最先端部に対応する目標肉厚が得られるように設定し
ておき、中空素管22の先端が第5スタンド20Eに噛
み込んでから、該第5スタンド20Eのロール間隔Gを
先端部に対して予め定められているロール間隔のパター
ンに沿うよう拡開を開始する。More specifically, initially, the roll gap G of the fifth and sixth stands 20E, 20F is set so as to obtain a target wall thickness corresponding to the most distal end of the finish rolling stock pipe. , The tip of the hollow shell 22 is bitten into the fifth stand 20E, and then the roll gap G of the fifth stand 20E is expanded so as to follow the pattern of the roll gap predetermined with respect to the tip portion. .
【0031】中空素管22が進行して先端の減肉予定部
分が第5スタンド20Eを通過し終わると同時に、その
ロール間隙Gは素管長手方向中央部のロール間隙とす
る。第6スタンド20Fについても同様である。At the same time as the hollow shell 22 advances and the portion where the wall thickness is to be thinned passes through the fifth stand 20E, at the same time, the roll gap G becomes the roll gap at the central portion in the longitudinal direction of the shell. The same applies to the sixth stand 20F.
【0032】次に、仕上圧延用素管の後端部の圧下開始
部に相当する部分が第5スタンド20Eに到達すると同
時に、該第5スタンド20Eのロール間隙Gはそれまで
の素管長手方向中央部に対するロール間隙から中空素管
22の後端部に対して定められているロール間隙のパタ
ーンに沿うように閉じ始める。Next, at the same time that the portion corresponding to the rolling start portion of the rear end of the finish rolling stock pipe reaches the fifth stand 20E, at the same time, the roll gap G of the fifth stand 20E changes the longitudinal direction of the stock pipe up to that point. From the roll gap with respect to the central portion, it starts to close along the pattern of roll gaps defined for the rear end of the hollow shell 22.
【0033】中空素管22の後端部が第5スタンド20
Eを尻抜けするときには、該第5スタンド20Eのロー
ル間隙Gは素管の最後端部に対応する目標肉厚が得られ
るロール間隙とされる。第6スタンド20Fについても
同様である。The rear end of the hollow shell 22 is the fifth stand 20.
When trailing through E, the roll gap G of the fifth stand 20E is set to a roll gap that achieves the target wall thickness corresponding to the rearmost end of the tube. The same applies to the sixth stand 20F.
【0034】なお、以上のようなロール間隙の制御パタ
ーンは使用する孔型ロール26の孔型形状、中空素管2
2の寸法、圧延速度等を考慮して決定される。The control pattern of the roll gap as described above has the hole shape of the hole roll 26 to be used and the hollow shell 2
2 dimensions, rolling speed, etc. are taken into consideration.
【0035】上記圧延制御を前記(1)式の条件の範囲
で行うと、被圧延素管の全長にわたって圧延後のマンド
レルバーの引き抜き不良及びバルジング疵の発生を回避
することができる。When the above rolling control is performed within the range of the condition of the above formula (1), it is possible to avoid the pulling-out failure of the mandrel bar and the occurrence of bulging defects over the entire length of the material pipe to be rolled.
【0036】本発明者の実験によれば、上記のようなロ
ール配列と制御パターンを持つマンドレルミルによっ
て、表1に示すそれぞれの寸法の孔型ロールを前記第
5、第6スタンド20E、20Fに組み込んで、外径1
00〜120mm、肉厚13.5mmの炭素鋼中空素管
を、直径64〜85mmのマンドレルバーを用いて、外
径80〜100mm、長手方向中央部の肉厚6.0m
m、最先後端部の肉厚3.0〜5.0mm、最先後端部
から1mの位置で素管長手方向中央部の肉厚と等しくな
るように最先後端部から直線上に肉厚を変化させるよう
に仕上圧延用素管を圧延した結果、表1のバジル幅の欄
に示されるように、図1に示される最適範囲の上側領域
でバルジングが発生し、且つ下側領域でストリッピング
ミスが発生することが確認された。According to an experiment conducted by the present inventor, the mandrel mill having the roll arrangement and the control pattern as described above was used to transfer the hole type rolls having the respective sizes shown in Table 1 to the fifth and sixth stands 20E and 20F. Built-in, outer diameter 1
A carbon steel hollow shell having a wall thickness of 0 to 120 mm and a wall thickness of 13.5 mm is used, using a mandrel bar having a diameter of 64 to 85 mm, an outer diameter of 80 to 100 mm, and a wall thickness of 6.0 m at the center in the longitudinal direction.
m, the thickness of the front and rear end part is 3.0 to 5.0 mm, and the thickness is straight from the front and rear end part to be equal to the thickness of the central part in the longitudinal direction of the raw pipe at a position 1 m from the front and rear end part. As a result of rolling the finishing rolling pipe so as to change the value, as shown in the column of basil width in Table 1, bulging occurs in the upper region of the optimum range shown in FIG. 1 and strike occurs in the lower region. It was confirmed that ripping mistakes occurred.
【0037】即ち、バルジ幅測定装置32E、32Fに
より測定されたバルジ幅が下限値を下回ると、被圧延素
管の内周長が過小となりストリッピングミスを発生さ
せ、バルジ幅が上限値を上回ると、被圧延素管が孔型ロ
ールフランジ部よりはみ出し、バルジング疵を発生させ
ることが確認された。That is, when the bulge width measured by the bulge width measuring devices 32E and 32F is less than the lower limit value, the inner peripheral length of the material tube to be rolled becomes too small and stripping error occurs, and the bulge width exceeds the upper limit value. It was confirmed that the material pipe to be rolled out protruded from the hole type roll flange portion to generate bulging defects.
【0038】[0038]
【表1】 [Table 1]
【0039】[0039]
【発明の効果】本発明は上記のように構成したので、マ
ンドレルバーを装入した中空素管を延伸圧延機により延
伸圧延を行う際に、中空素管の両管端部薄肉化圧延を実
施する場合において、圧延後のマンドレルバーの引き抜
き不良、及び、バルジング疵の発生を解消することがで
きる。EFFECTS OF THE INVENTION Since the present invention is configured as described above, when the hollow shell containing the mandrel bar is stretch-rolled by the stretch-rolling machine, both ends of the hollow shell are thinned and rolled. In this case, it is possible to prevent the pulling-out failure of the mandrel bar after rolling and the occurrence of bulging defects.
【図1】本発明による条件によって鋼管を延伸圧延した
結果と条件外の延伸圧延の結果とを比較して示す線図FIG. 1 is a diagram showing a result of drawing and rolling a steel pipe under the conditions according to the present invention and a result of drawing and rolling under other conditions.
【図2】本発明方法を実施するための延伸圧延機を示す
略示平面図FIG. 2 is a schematic plan view showing a drawing and rolling mill for carrying out the method of the present invention.
【図3】本発明方法を実施するための延伸圧延機におけ
る孔型ロールを示す断面図FIG. 3 is a sectional view showing a hole-type roll in a drawing and rolling mill for carrying out the method of the present invention.
【図4】継目無鋼管の製造過程を示す工程図FIG. 4 is a process diagram showing a manufacturing process of a seamless steel pipe.
【図5】仕上圧延用素管の先後端部の肉厚分布を示す線
図FIG. 5 is a diagram showing the wall thickness distribution at the front and rear ends of the finish rolling stock pipe.
【図6】先後端部薄肉化制御を実施した仕上圧延用素管
を示す略示断面図FIG. 6 is a schematic cross-sectional view showing a raw tube for finish rolling in which front and rear end thinning control is performed.
20…延伸圧延機 20E…第5スタンド 20F…第6スタンド 22…中空素管 24…マンドレルバー 26…孔型ロール 26A…溝 26B…フランジ部 26C…逃げ部 26D…溝底部 30…制御装置 32E、32F…バルジ幅測定装置 G…ロール間隙 20 ... Stretching and rolling mill 20E ... Fifth stand 20F ... Sixth stand 22 ... Hollow shell 24 ... Mandrel bar 26 ... Hole roll 26A ... Groove 26B ... Flange portion 26C ... Escape portion 26D ... Groove bottom portion 30 ... Control device 32E, 32F ... Bulge width measuring device G ... Roll gap
Claims (1)
型ロールをそれぞれに備えた複数のスタンドによって構
成される連続延伸圧延機により延伸圧延を行う際に、後
工程の絞り圧延機における管先後端部の厚肉化を抑制す
るために前記延伸圧延機で予め管の先後端部の肉厚を減
肉するように圧下位置を制御する管の延伸圧延制御方法
において、前記圧下位置制御を実施する延伸圧延機のス
タンドにおける孔型ロールの溝からフランジ部に至る逃
げ部の曲率をR3、溝底部からフランジ部までの溝底深
さをDKとしたとき、前記フランジ部のロール間隙G
を、圧延先端から圧延後端の全長にかけて、 −0.67G/DK+0.4≦R3/DK≦−G/DK
+0.8 の範囲に制御することを特徴とする鋼管の延伸圧延制御
方法。1. A pipe in a draw-rolling machine in a post-process when a hollow shell having a mandrel bar inserted therein is stretch-rolled by a continuous stretch-rolling machine composed of a plurality of stands each having a hole-type roll. In the method for controlling the stretching and rolling of the pipe, which controls the rolling position to reduce the wall thickness of the front and rear ends of the pipe in advance in the stretching rolling machine in order to suppress the thickening of the front and rear ends, the rolling position control is performed. When the curvature of the clearance portion from the groove of the hole-type roll to the flange portion in the stand of the stretch rolling mill to be carried out is R3 and the groove bottom depth from the groove bottom portion to the flange portion is DK, the roll gap G of the flange portion is
Is −0.67 G / DK + 0.4 ≦ R3 / DK ≦ −G / DK from the rolling front end to the rolling rear end.
A method for controlling the stretching and rolling of a steel pipe, which is characterized by controlling within a range of +0.8.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP17347995A JP3624235B2 (en) | 1995-07-10 | 1995-07-10 | Method for controlling the drawing and rolling of steel pipes |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP17347995A JP3624235B2 (en) | 1995-07-10 | 1995-07-10 | Method for controlling the drawing and rolling of steel pipes |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0924408A true JPH0924408A (en) | 1997-01-28 |
JP3624235B2 JP3624235B2 (en) | 2005-03-02 |
Family
ID=15961264
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP17347995A Expired - Fee Related JP3624235B2 (en) | 1995-07-10 | 1995-07-10 | Method for controlling the drawing and rolling of steel pipes |
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Country | Link |
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JP (1) | JP3624235B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113231478A (en) * | 2021-05-17 | 2021-08-10 | 莱芜钢铁集团电子有限公司 | Device for accurately positioning bar rolling line and control method |
-
1995
- 1995-07-10 JP JP17347995A patent/JP3624235B2/en not_active Expired - Fee Related
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113231478A (en) * | 2021-05-17 | 2021-08-10 | 莱芜钢铁集团电子有限公司 | Device for accurately positioning bar rolling line and control method |
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---|---|
JP3624235B2 (en) | 2005-03-02 |
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