JPH10258312A - Manufacture of welded tube excellent in roundness - Google Patents

Manufacture of welded tube excellent in roundness

Info

Publication number
JPH10258312A
JPH10258312A JP6276297A JP6276297A JPH10258312A JP H10258312 A JPH10258312 A JP H10258312A JP 6276297 A JP6276297 A JP 6276297A JP 6276297 A JP6276297 A JP 6276297A JP H10258312 A JPH10258312 A JP H10258312A
Authority
JP
Japan
Prior art keywords
pipe
roll
welded
roundness
diameter
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
Application number
JP6276297A
Other languages
Japanese (ja)
Other versions
JP3990761B2 (en
Inventor
Takefumi Nakako
武文 仲子
Shoji Inoue
正二 井上
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 Nisshin Co Ltd
Original Assignee
Nisshin Steel Co 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
Application filed by Nisshin Steel Co Ltd filed Critical Nisshin Steel Co Ltd
Priority to JP06276297A priority Critical patent/JP3990761B2/en
Publication of JPH10258312A publication Critical patent/JPH10258312A/en
Application granted granted Critical
Publication of JP3990761B2 publication Critical patent/JP3990761B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

PROBLEM TO BE SOLVED: To obtain the welded tube of product having high roundness in all of the tip, rear end and the middle. SOLUTION: After bending a metallic strip 2 in the width direction and executing butt welding 7 of both end parts in the width direction in a state where the cross section is held in an approximately round shape, the welded tube stock 8 is flatly worked with over-bend rolls 9 so that the distance from the weld zone to the tube-bottom part becomes smaller than the targeted outside diameter of product and, next, the welded tube stock is formed into an approximately round shape with straightening rolls 11. In flattening work, it is preferable to flatten the welded tube stock so that the distance from the weld zone to the tube-bottom part is 3-10% smaller than the targeted outside diameter of product. When the out-of-roundness in the middle part of the tube is degraded by the flattening work, the rolling reduction with the straightening rolls 11 is adjusted in accordance with the amount of flattening with the over-bend rolls 9. Then, because residual stress is removed by the flattening work and straightening, the roundness of the welded tube of product which is obtained by cutting the welded tube stock 8 into standard length is not degraded even at the tube ends.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【産業上の利用分野】本発明は、管端部を含め全長にわ
たって真円度に優れた溶接管を製造する方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a welded pipe having excellent roundness over its entire length including the pipe end.

【0002】[0002]

【従来の技術】溶接管をロール成形法で製造する場合、
所定幅にスリットされた金属帯が管素材として使用され
る。金属帯は、多段配置された各成形スタンドで幅方向
に順次曲げ加工され、最終的には幅方向両端部を突き合
せた円筒形状に成形される。次いで、幅方向両端部を突
合せ溶接し、素管を得る。この素管をサイジング工程に
通し、複数段の成形ロールで管の直径を絞り寸法精度及
び真円度を向上させている。その後、定寸切断され、製
品管となる。ロール成形法では、成形スタンドの多段配
置が必要とされる。しかも、製造しようとする管の直径
が異なると、それに応じて各スタンドの成形ロールを組
み替えることが要求される。成形ロールの組替えや各ス
タンド間の調整は、非常に面倒な作業であり、生産性を
向上させる上でのネックとなる。そこで、本発明者等
は、金属帯に曲げ・曲げ戻し歪みを付与するとき金属帯
が板幅方向にカールする性質を利用し、多数の成形ロー
ルを必要としないロールレスフォーミング法を開発した
(特公平6−77773号公報)。この方法では、板幅
方向と平行な小径の曲げロールによって、管内面となる
面を内側にして金属帯を連続的に曲げ・曲げ戻し加工
し、曲げ・曲げ戻しによる板幅方向の曲がりを利用して
金属帯を円筒形状に成形する。
2. Description of the Related Art When a welded pipe is manufactured by a roll forming method,
A metal strip slit to a predetermined width is used as a tube material. The metal strip is sequentially bent in the width direction at each of the forming stands arranged in multiple stages, and is finally formed into a cylindrical shape in which both ends in the width direction are abutted. Next, the both ends in the width direction are butt-welded to obtain a raw tube. This raw tube is passed through a sizing process, and the diameter of the tube is reduced by a plurality of forming rolls to improve dimensional accuracy and roundness. Then, it is cut to a fixed size to form a product tube. In the roll forming method, a multi-stage arrangement of forming stands is required. Moreover, if the diameter of the tube to be manufactured is different, it is required to change the forming rolls of each stand accordingly. Changing the forming rolls and adjusting between the stands is a very troublesome operation, and is a bottleneck in improving productivity. Therefore, the present inventors have developed a rollless forming method that does not require a large number of forming rolls by utilizing the property that the metal band curls in the plate width direction when bending and bending-back distortion is applied to the metal band ( Japanese Patent Publication No. 6-77773. In this method, a metal strip is continuously bent and bent back with the inner surface of the pipe inside using a small-diameter bending roll parallel to the sheet width direction, and the bending in the sheet width direction due to bending and bending back is used. To form a metal strip into a cylindrical shape.

【0003】[0003]

【発明が解決しようとする課題】ロール成形法による造
管では、ロール表面が接触する管の周方向位置に応じて
ロール表面の曲率が異なる。そのため、管の周方向位置
に応じて、成形ロールによって受ける加工の形態や歪み
量等が異なる。このような成型工程を経た溶接管には管
周方向に沿ってバラツキのある応力分布が内在してお
り、管を切断した際に切断端面の断面形状が残留応力に
よって変化し、結果として管端部の真円度を低下させ
る。特に製造しようとする溶接管が肉厚比(肉厚/管外
径)の小さい薄肉管や高強度材料からなる管である場
合、真円度が低下する傾向が顕著になる。ロールレスフ
ォーミング法で造管した場合にも、ロール成形法ほどで
はないが、依然として管端部における真円度の低下がみ
られる。本発明は、このような問題を解消すべく案出さ
れたものであり、溶接後の扁平加工によって残留応力を
開放し、管端部でも残留応力に起因した変形を抑え、真
円度の高い溶接管を製造することを目的とする。
In the pipe forming by the roll forming method, the curvature of the roll surface varies depending on the circumferential position of the pipe in contact with the roll surface. Therefore, depending on the circumferential position of the tube, the form of processing and the amount of distortion received by the forming rolls are different. The welded pipe that has undergone such a forming process has an inherent stress distribution that varies along the pipe circumferential direction, and when the pipe is cut, the cross-sectional shape of the cut end surface changes due to residual stress. Lowers the roundness of the part. In particular, when the welded pipe to be manufactured is a thin-walled pipe having a small thickness ratio (wall thickness / outer diameter of the pipe) or a pipe made of a high-strength material, the roundness tends to be reduced. Even when the pipe is formed by the rollless forming method, the roundness at the pipe end is still reduced, though not as much as the roll forming method. The present invention has been devised to solve such a problem, and releases residual stress by flattening after welding, suppresses deformation caused by residual stress even at the pipe end, and has a high roundness. The purpose is to manufacture welded tubes.

【0004】[0004]

【課題を解決するための手段】本発明の溶接管製造方法
は、その目的を達成するため、金属帯を板幅方向に曲げ
加工し、断面をほぼ真円形状に保持した状態で板幅方向
両端部を突合せ溶接した後、溶接部から管底部までの距
離が目標製品外径よりも小さくなるように溶接素管をオ
ーバベンドロールで扁平加工し、次いで溶接素管をほぼ
真円形状に矯正ロールで成形することを特徴とする。扁
平加工では、溶接部から管底部までの距離が目標製品外
径よりも3〜10%小さくなるように溶接素管を扁平加
工することが好ましい。扁平加工によって管端の真円度
が確保されるが、管中央部の真円度が低下する場合があ
る。このような場合には、式(1)で与えられる数値が
5〜11の範囲になるように、オーバベンドロールによ
る扁平率に応じて矯正ロールによる直径絞り率を調整す
ることが好ましい。 扁平率(%)+10×直径絞り率(%)・・・・(1)
In order to achieve the object, a method for manufacturing a welded pipe according to the present invention is such that a metal strip is bent in the sheet width direction and the cross section is maintained in a substantially circular shape in the sheet width direction. After butt-welding the ends, the welded tube is flattened with an overbend roll so that the distance from the welded portion to the tube bottom is smaller than the target product outer diameter, and then the welded tube is straightened into a substantially circular shape It is characterized by being formed by a roll. In the flattening, it is preferable to flatten the welded tube so that the distance from the welded portion to the tube bottom is smaller than the target product outer diameter by 3 to 10%. The roundness of the pipe end is ensured by the flattening, but the roundness of the central part of the pipe may be reduced. In such a case, it is preferable to adjust the diameter reduction ratio by the straightening roll according to the flatness by the overbend roll so that the numerical value given by Expression (1) is in the range of 5 to 11. Flatness rate (%) + 10 × diameter drawing rate (%) ... (1)

【0005】[0005]

【実施の形態】ロール成形法による造管では、金属帯が
各成形スタンドで板幅方向に順次曲げられ、円筒状に成
形される。また、図1に示すロールレスフォーミング法
では、アンコイラ1から巻き出された金属帯2は、小径
ロール3により曲げ・曲げ戻し加工される。金属帯2
は、曲げ・曲げ戻し加工で生じた板幅方向の曲がりによ
って、サイドロール4に至る過程で板幅方向にカール
し、円筒形状に変形する。円筒状に成形された金属帯2
は、シームガイドロール5で板幅方向両端部を案内され
ながらスクイズロール6に送り込まれ、板幅方向両端部
が溶接装置7で突合せ溶接される。溶接素管8は、オー
バベンドロール9で扁平加工された後、引抜き装置10
を経て矯正ロール11で真円形状に加工される。次い
で、切断装置12により定寸切断され、製品溶接管とな
る。
DESCRIPTION OF THE PREFERRED EMBODIMENTS In a tube forming by a roll forming method, a metal band is sequentially bent in a sheet width direction at each forming stand and formed into a cylindrical shape. In the rollless forming method shown in FIG. 1, the metal band 2 unwound from the uncoiler 1 is bent / unbent by a small-diameter roll 3. Metal strip 2
Is curled in the plate width direction in the process of reaching the side rolls 4 due to the bending in the plate width direction generated by the bending / unbending process, and is deformed into a cylindrical shape. Metal strip 2 formed into a cylindrical shape
Is fed to the squeeze roll 6 while being guided at both ends in the sheet width direction by the seam guide rolls 5, and both ends in the sheet width direction are butt-welded by the welding device 7. After the welding pipe 8 is flattened by the overbend roll 9, the drawing device 10 is used.
After that, it is processed into a perfect circular shape by the straightening roll 11. Next, it is cut to a fixed size by the cutting device 12 to form a product welded pipe.

【0006】ロール成形法及びロールレスフォーミング
法の何れにおいても、程度の差はあれ、金属帯1を筒状
に成形する過程で発生する歪みの形態や大きさが金属帯
1の板幅方向に関して異なる。また、溶接素管8の断面
形状を矯正ロール11で調整する際にも、矯正ロール1
1から受ける歪みは、溶接素管8の円周方向に関して一
様でない。このように、複雑な変形経路を経た溶接素管
8には円周方向に沿って不均一な残留応力が分布してお
り、また残留応力の分布状態を予め把握することはでき
ない。残留応力は、管端部から離れた箇所では釣り合っ
た状態にある。そのため、矯正ロール11による矯正条
件を適正に選定するとき、溶接素管8の真円度を確保で
きる。しかし、溶接素管8が切断されると、切断端面近
傍における残留応力の釣合い状態が崩れ、管端が変形し
た状態で再び残留応力が釣り合う。そのため、溶接素管
8の真円度が良好となるように矯正条件を選定しても、
溶接素管8を切断して得た製品溶接管では管端部近傍の
真円度が悪化する。
[0006] In both the roll forming method and the rollless forming method, the shape and magnitude of the distortion generated in the process of forming the metal band 1 into a cylindrical shape vary with respect to the width direction of the metal band 1. different. Also, when adjusting the cross-sectional shape of the welding pipe 8 with the straightening roll 11, the straightening roll 1
The distortion from 1 is not uniform in the circumferential direction of the welding pipe 8. As described above, the non-uniform residual stress is distributed along the circumferential direction in the weld pipe 8 having passed through the complicated deformation path, and the distribution state of the residual stress cannot be grasped in advance. The residual stress is in a state of being balanced at a position away from the pipe end. Therefore, when the straightening condition by the straightening roll 11 is properly selected, the roundness of the welding pipe 8 can be ensured. However, when the weld pipe 8 is cut, the balance of the residual stress in the vicinity of the cut end face is broken, and the residual stress is balanced again with the pipe end deformed. Therefore, even if the straightening condition is selected so that the roundness of the welding pipe 8 becomes good,
In a product weld pipe obtained by cutting the weld pipe 8, roundness near the pipe end deteriorates.

【0007】本発明においては、このような残留応力の
釣り合い状態が崩れた結果である変形を防止するため、
スクイズロール6でほぼ真円状に保持した状態で金属帯
1を溶接した後、溶接部から管底部までの距離を目標製
品外径よりも小さくなるようにオーバベンドロール9で
扁平化している。オーバベンドロール9としては、ロー
ル最小径部を含む部分に目標製品半径×1.1〜1.4
程度の半径をもつカリバーを付けたロールが好ましい。
このようなオーバベンドロール9により、目標製品外径
を基準として3〜10%の扁平量で溶接素管8が扁平加
工される。カリバー形状については、目標製品半径に等
しい半径のカリバーでは全く扁平化することが困難であ
るため、目標製品半径よりも大きな半径をもつカリバー
にすることが必要である。具体的には、目標製品半径の
1〜1.4倍程度の半径をもつカリバーで所望の扁平変
形を実施することが可能である。扁平化に引き続いて実
施される矯正ロールによる直径絞り加工と併用して良好
な管の真円度を確保するためには、表1に示すように溶
接管直径の3〜10%の範囲に扁平率を調整し、更に式
(1)で与えられる数値を5〜11の範囲に規制する必
要がある。 扁平率(%)+10×直径絞り率 ・・・・(1)
In the present invention, in order to prevent deformation as a result of such a state in which the residual stress is out of balance,
After the metal strip 1 is welded while being held in a substantially perfect shape by the squeeze roll 6, the overbend roll 9 flattens the distance from the welded portion to the pipe bottom so as to be smaller than the target product outer diameter. As the overbend roll 9, a target product radius × 1.1 to 1.4 is added to a portion including the roll minimum diameter portion.
Rolls with calibers of a moderate radius are preferred.
By such an overbend roll 9, the welding blank 8 is flattened with a flattening amount of 3 to 10% based on the target product outer diameter. Regarding the caliber shape, it is difficult to flatten the caliber with a radius equal to the target product radius at all, so it is necessary to make the caliber a radius larger than the target product radius. Specifically, it is possible to perform a desired flat deformation with a caliber having a radius of about 1 to 1.4 times the target product radius. As shown in Table 1, in order to secure good roundness of the pipe in combination with diameter drawing by a straightening roll performed following flattening, the flattened pipe is flattened within a range of 3 to 10% of the diameter of the welded pipe. It is necessary to adjust the rate and further restrict the numerical value given by the equation (1) to a range of 5 to 11. Flatness rate (%) + 10 x diameter drawing rate ... (1)

【0008】 [0008]

【0009】扁平率が溶接管直径の3〜10%の範囲を
外れ、或いは式(1)で与えられる数値が5〜11の範
囲を外れると、図2に示すように真円度が悪化する。ま
た、溶接直後の管の断面は、溶接部が高温のため他の部
分よりも強度が低いことから残留応力によって溶接部が
屋根状に変形したいわゆるルーフィングと呼ばれる減少
が生じ、溶接部を上側にした場合に縦長の断面形状にな
る。そのため、扁平方向としては溶接後の管を上下から
圧下して横長形状とし、管断面全体及び溶接部近傍の形
状を改善することが必要である。溶接素管8を扁平加工
すると、新たな残留応力が発生する。この残留応力は、
それまでの加工履歴によって発生していた残留応力の影
響をほぼ除去する。扁平加工で発生した残留応力は、溶
接素管8を矯正ロール11で真円形状に成形するときに
発生する逆方向の残留応力で相殺される。そのため、矯
正ロール11を通過した溶接素管8は、成形後に溶接し
たままの状態に比較して残留応力が大幅に少なくなって
いる。したがって、溶接素管8を定寸切断しても、切断
端面に口開き,口閉じ等の変形が発生することがなくな
る。扁平加工が真円度の向上に及ぼす影響は、製品溶接
管の中央,先端,後端で異なる傾向を示す。すなわち、
扁平量の増大に従って管端では必要な真円度が維持され
るものの、管中央では過度に扁平化される虞れがある。
このような場合、矯正ロール11で溶接素管8の直径を
絞る加工を施し、その圧下量を調節することにより管中
央の真円度も確保される。
If the flatness is out of the range of 3 to 10% of the diameter of the welded pipe, or if the numerical value given by the equation (1) is out of the range of 5 to 11, the roundness deteriorates as shown in FIG. . In addition, the cross section of the pipe immediately after welding has a so-called roofing in which the weld is deformed into a roof shape due to residual stress because the weld is hot and has lower strength than the other parts. In this case, a vertically long cross-sectional shape is obtained. Therefore, it is necessary to improve the shape of the entire cross section of the pipe and the vicinity of the welded portion by pressing down the pipe after welding from above and below to make the pipe flat in the flat direction. When the welding pipe 8 is flattened, new residual stress is generated. This residual stress is
The effect of the residual stress generated by the processing history up to that point is almost eliminated. The residual stress generated in the flattening is offset by the residual stress in the opposite direction generated when the welding pipe 8 is formed into a perfect circular shape by the straightening roll 11. Therefore, the residual stress of the welding pipe 8 that has passed through the straightening roll 11 is significantly reduced as compared to the state where the pipe 8 remains welded after forming. Therefore, even when the welding tube 8 is cut to a fixed size, deformation such as opening and closing of the mouth does not occur on the cut end surface. The effect of flattening on the improvement of roundness shows a different tendency at the center, tip and rear end of the product welded pipe. That is,
The required roundness is maintained at the pipe end as the flattening amount increases, but the pipe may be excessively flattened at the center.
In such a case, the roundness of the center of the pipe is secured by performing a process of reducing the diameter of the welding pipe 8 with the straightening roll 11 and adjusting the amount of reduction.

【0010】[0010]

【実施例】管素材として、C:0.065重量%,S
i:0.50重量%,Mn:0.30重量%,P:0.
025重量%,S:0.001重量%,Ni:2.00
重量%,Cr:16.30重量%,N:0.010重量
%の組成をもち、板厚0.35mm,0.2%耐力93
5MPa,引張強さ1170MPa,伸び9.0%,ビ
ッカース硬さHV380の高強度ステンレス鋼帯を使用
した。このステンレス鋼帯を幅79.3mmにスリット
加工し、図1に示すように鋼帯2の板幅方向と平行に配
置された直径8mmの小径曲げロール3で鋼帯2の長手
方向に連続的に曲げ・曲げ戻し加工を施した。曲げ・曲
げ戻し加工で発生した板幅方向の反りを利用して鋼帯2
を円筒状に成形し、スクイズロール6で断面をほぼ真円
状に保持した状態で、鋼帯2の板幅方向両端部を溶接速
度10m/分で突合せTIG溶接した。スクイズロール
6としては、図3に示すように直径ds=25.4mm
のギャップを形成するロール対を使用した。
EXAMPLE As a pipe material, C: 0.065% by weight, S
i: 0.50% by weight, Mn: 0.30% by weight, P: 0.
025% by weight, S: 0.001% by weight, Ni: 2.00
%, Cr: 16.30% by weight, N: 0.010% by weight, thickness 0.35 mm, 0.2% proof stress 93
A high-strength stainless steel strip of 5 MPa, tensile strength of 1170 MPa, elongation of 9.0%, and Vickers hardness HV380 was used. This stainless steel strip is slit into a width of 79.3 mm, and is continuously cut in the longitudinal direction of the steel strip 2 by a small-diameter bending roll 3 having a diameter of 8 mm arranged in parallel with the width direction of the steel strip 2 as shown in FIG. Was subjected to bending and bending back processing. Steel strip 2 utilizing the warpage in the sheet width direction generated by bending and unbending
Was formed into a cylindrical shape, and both ends of the steel strip 2 in the sheet width direction were butt-welded at a welding speed of 10 m / min with the squeeze roll 6 holding the cross section in a substantially circular shape. As shown in FIG. 3, the squeeze roll 6 has a diameter d s = 25.4 mm.
Roll pairs forming a gap of.

【0011】引き続き、溶接部から管底部までの距離が
目標製品外径25.4mmよりも小さくなるように、オ
ーバベンドロール9により溶接素管8を扁平加工した。
オーバベンドロール9には、図4に示すカリバー半径R
B =15.5mm,ロール底径D1 =60mm,ロール
胴径D2 =82mmのロール対を使用した。また、適正
扁平量に対応したカリバーをもつオーバベンドロール9
として、図5に示すようにカリバーの長半径RB1=1
6.04mm,短半径RB2=11.03mm,ロール底
径D1 =60mm,ロール胴径D2 =82.4mmのロ
ール対を使用した。なお、図4のロールは、ロール合せ
部で管と接触しない領域が生じる。図5のロールでは、
総型でほぼ円周方向全体にわたって管表面に接触する。
この点、図5のロールの法がロールわせ部での局部的な
折れ変形が生じないことから、図5のロールの方が好ま
しい。扁平加工後の溶接素管8を引抜き装置10で引き
抜いた後、直径方向の絞り加工を加えない状態で矯正ロ
ール11により溶接素管8をほぼ真円形状に成形した。
矯正ロール11としては、図6に示すように直径dc
25.4mmのギャップを形成する底径D3 =60mm
のロール対を使用した。成形後の溶接素管8を定寸切断
し、直径25.4mmの製品溶接管を得た。
Subsequently, the welding blank 8 was flattened by the overbend roll 9 such that the distance from the welded portion to the bottom of the tube was smaller than the target product outer diameter of 25.4 mm.
The overbend roll 9 has a caliber radius R shown in FIG.
A roll pair having B = 15.5 mm, roll bottom diameter D 1 = 60 mm, and roll body diameter D 2 = 82 mm was used. Also, an overbend roll 9 having a caliber corresponding to an appropriate flattening amount.
As shown in FIG. 5, the major radius of the caliber R B1 = 1
6.04Mm, short radius R B2 = 11.03mm, roll bottom diameter D 1 = 60 mm, it was used roll pairs of the roll barrel diameter D 2 = 82.4mm. The roll of FIG. 4 has a region where the roll does not come into contact with the pipe at the roll joining portion. In the roll of FIG.
It contacts the pipe surface almost entirely in the circumferential direction.
In this respect, the roll method shown in FIG. 5 is preferable because the roll method shown in FIG. 5 does not cause local bending deformation at the rolled portion. After the flattened welding tube 8 was pulled out by the drawing device 10, the welding tube 8 was formed into a substantially perfect shape by the straightening roll 11 without drawing in the diameter direction.
As shown in FIG. 6, the straightening roll 11 has a diameter d c =
Bottom diameter D 3 = 60 mm forming a gap of 25.4 mm
Roll pairs were used. The formed weld pipe 8 was cut to a fixed size to obtain a product weld pipe having a diameter of 25.4 mm.

【0012】扁平加工に際し、扁平量を0mmから3m
mまで変化させ、定寸切断された製品溶接管の先端,中
央及び後端における真円度(縦径−横径)を測定した。
図7の測定結果にみられるように、扁平加工を施さない
製品溶接管では、真円度が管外径の4%を超える値とな
っていた。扁平量0の条件は、表1のNo.1と異なり、
扁平ロールの圧下を0としたものであるので、溶接部の
ルーフィング形状がそのまま残留し、管中央が極端な縦
長となったものである。通常、中央の真円度がある程度
確保された場合は、管端の形状が崩れる場合が多い。し
かし、このような極端な条件の場合では、残留応力のバ
ランスにより管端が依然として縦長ではあるものの、極
端に縦長な中央に対しては縦長の程度が減少する方向に
変形したものと推察される。他方、扁平加工した製品溶
接管では、何れの位置においても扁平量の増大に伴って
管断面が縦長から横長となる傾向がみられた。なかで
も、扁平量がおおよそ1.5〜2mmの範囲で扁平加工
すると、先端,中央及び後端の何れにおいても真円度が
管外径の1%程度以内の良好な形状をもつ製品溶接管が
得られた。1.5〜2mmの扁平量は、目標製品外径の
5.9〜7.9%に相当する。
In flattening, the flattening amount is from 0 mm to 3 m
m, and the roundness (longitudinal diameter-horizontal diameter) at the front end, the center, and the rear end of the product welded pipe cut to the fixed size was measured.
As can be seen from the measurement results of FIG. 7, the roundness of the product welded pipe not subjected to flattening was a value exceeding 4% of the pipe outer diameter. The condition of flatness 0 is different from No. 1 in Table 1,
Since the reduction of the flat roll was set to 0, the roofing shape of the welded portion remained as it was, and the center of the pipe became extremely elongated vertically. Normally, when a certain degree of roundness at the center is secured, the shape of the pipe end often collapses. However, in the case of such extreme conditions, although the pipe end is still vertically elongated due to the balance of the residual stress, it is presumed that the extremely vertically elongated center is deformed in a direction in which the degree of the elongated shape is reduced. . On the other hand, in the flat product welded pipe, the pipe section tended to change from vertical to horizontal with increasing flatness at any position. In particular, when the flattening is performed with the flattening amount in the range of about 1.5 to 2 mm, the product welded pipe has a good shape with roundness of about 1% or less of the outer diameter of the pipe at any of the front, center, and rear ends. was gotten. The flatness of 1.5 to 2 mm corresponds to 5.9 to 7.9% of the target product outer diameter.

【0013】扁平量の増大に従って縦長から横長に変化
する割合は、図8に示されているように、先端及び後端
に比較して管中央で大きい。そのため、先端及び後端に
おける真円度を確保するように扁平量を設定すると、管
中央では過度に扁平化された横長になる虞れがある。そ
こで、扁平量を2mmに固定して矯正ロール11を最大
0.15mmまで圧下することにより、溶接素管8の直
径を絞る加工を施した。この場合、図8に示すように圧
下量の増大に伴って製品溶接管の中央が横長から縦長に
なり、先端及び後端では縦長から横長になる傾向がみら
れた。この結果から、扁平加工によるとき管中央部分及
び管端部の断面形状が同時に所望の範囲に納まらない場
合でも、矯正ロール11による圧下量調整を扁平加工に
組み合わせることにより、長手方向に関してほぼ同じ断
面形状をもつ製品溶接管が得られることが判る。扁平量
と矯正ロール11の圧下量との適正な関係は、各ロール
の直径,ロールスタンドの配置,直径,板厚等の管の寸
法,材料特性等の要因によって残留応力自体の大きさが
変化することから一概に定めることができない。そのた
め、両者の関係を実験的に求めることが必要であるが、
実施した条件下では扁平量については管外径の3〜10
%程度,矯正ロール11の圧下による管直径の絞り量に
ついては管外周長の0〜0.5%程度であった。
As shown in FIG. 8, the ratio of change from the vertical to the horizontal as the flattening amount increases is larger at the center of the tube than at the front and rear ends. Therefore, if the flatness is set so as to secure the roundness at the front end and the rear end, there is a possibility that the center of the pipe may become excessively flattened horizontally. Therefore, the flattening amount was fixed to 2 mm, and the straightening roll 11 was pressed down to a maximum of 0.15 mm, thereby performing a process of reducing the diameter of the welding pipe 8. In this case, as shown in FIG. 8, there was a tendency that the center of the product welded pipe was changed from the horizontal to the vertical, and the front and rear ends were changed from the vertical to the horizontal as the reduction amount was increased. From this result, even when the cross-sectional shapes of the tube central portion and the tube end do not fall within the desired ranges at the same time when flattening is performed, the adjustment of the amount of reduction by the straightening roll 11 is combined with the flattening to obtain substantially the same cross section in the longitudinal direction. It can be seen that a product welded tube having a shape can be obtained. The appropriate relationship between the flattening amount and the amount of reduction of the straightening roll 11 is that the magnitude of the residual stress itself varies depending on factors such as the diameter of each roll, the arrangement of the roll stand, the dimensions of the pipe such as the diameter and plate thickness, and the material characteristics. Can not be determined in a straightforward manner. Therefore, it is necessary to experimentally determine the relationship between the two,
Under the conditions used, the flatness was 3 to 10 times the outer diameter of the tube.
%, And the amount of reduction of the pipe diameter due to the reduction of the straightening roll 11 was about 0 to 0.5% of the outer circumference of the pipe.

【0014】[0014]

【発明の効果】以上に説明したように、本発明において
は、溶接素管を扁平加工した後で矯正ロールにより真円
形状に成形することにより、造管時の残留応力が除去さ
れ、溶接素管を切断して製品溶接管とした場合に管端に
おいても真円度が低下することがない。そのため、残留
応力除去焼鈍を必要とせず、全長にわたって良好な断面
形状をもつ溶接管が安価に製造される。
As described above, in the present invention, by flattening a welded pipe and then forming it into a perfect circular shape by using a straightening roll, residual stress at the time of pipe making is removed, and When the pipe is cut into a product weld pipe, the roundness does not decrease even at the pipe end. Therefore, a welded pipe having a good cross-sectional shape over the entire length is manufactured at low cost without the need for annealing for removing residual stress.

【図面の簡単な説明】[Brief description of the drawings]

【図1】 本発明実施例で採用したロールレスフォーミ
ング法による造管ライン
FIG. 1 is a pipe production line by a rollless forming method employed in an embodiment of the present invention.

【図2】 成形条件が真円度に及ぼす影響Fig. 2 Effect of molding conditions on roundness

【図3】 図1の造管ラインにおけるスクイズロールの
プロフィール
FIG. 3 is a profile of a squeeze roll in the pipe making line of FIG.

【図4】 同造管ラインにおけるオーバベンドロールの
プロフィール
Fig. 4 Profile of overbend roll in the same pipe production line

【図5】 同造管ラインにおける他のオーバベンドロー
ルのプロフィール
FIG. 5 Profiles of other overbend rolls in the pipe production line

【図6】 同造管ラインにおける矯正ロールのプロフィ
ール
Fig. 6 Profile of straightening roll in the same tube making line

【図7】 扁平量が製品溶接管の真円度に及ぼす影響Fig. 7 Effect of flatness on roundness of product welded pipe

【図8】 矯正ロールの圧下量が製品溶接管の真円度に
及ぼす影響
FIG. 8: Effect of reduction amount of straightening roll on roundness of product welded pipe

【符号の説明】[Explanation of symbols]

1:アンコイラ 2:金属帯(鋼帯) 3:小径ロ
ール 4:サイドロール 5:シームガイドロール
6:スクイズロール 7:溶接装置 8:溶接素管 9:オーバベンドロール 10:引
抜き装置 11:矯正ロール 12:切断装置 ds :スクイズロールのクラウン直径 RB ,RB1,RB2:オーバベンドロールのカリバー半径 D1 :オーバベンドロールの底径 D2 :オーバ
ベンドロールの胴径 dc :矯正ロールのクラウン直径 D3 :矯正ロ
ールの底径
1: Uncoiler 2: Metal strip (steel strip) 3: Small-diameter roll 4: Side roll 5: Seam guide roll 6: Squeeze roll 7: Welding device 8: Welding tube 9: Overbend roll 10: Pulling device 11: Straightening roll 12: cutting device d s: crown diameter R B of squeeze rolls, R B1, R B2: over caliber of the bend roll radius D 1: over bend roll of the bottom diameter D 2: over-bend the roll body diameter d c: straightening rolls Diameter D 3 : Bottom diameter of straightening roll

Claims (3)

【特許請求の範囲】[Claims] 【請求項1】 金属帯を板幅方向に曲げ加工し、断面を
ほぼ真円形状に保持した状態で板幅方向両端部を突合せ
溶接した後、溶接部から管底部までの距離が目標製品外
径よりも小さくなるように溶接素管をオーバベンドロー
ルで扁平加工し、次いで溶接素管をほぼ真円形状に矯正
ロールで成形することを特徴とする真円度の優れた溶接
管の製造方法。
1. A metal strip is bent in a sheet width direction, and both ends in a sheet width direction are butt-welded in a state where a cross section is maintained in a substantially circular shape, and then a distance from a welded portion to a pipe bottom is out of a target product. A method of manufacturing a welded pipe having excellent roundness, wherein the welded pipe is flattened with an overbend roll so as to have a diameter smaller than the diameter, and then the welded pipe is formed into a substantially circular shape with a straightening roll. .
【請求項2】 溶接部から管底部までの距離が目標製品
外径よりも3〜10%小さくなるようにオーバベンドロ
ールで溶接素管を扁平加工する請求項1記載の真円度の
優れた溶接管の製造方法。
2. The roundness of the welded pipe according to claim 1, wherein the welded pipe is flattened by an overbend roll so that the distance from the welded portion to the pipe bottom is smaller than the target product outer diameter by 3 to 10%. Manufacturing method of welded pipe.
【請求項3】 オーバベンドロールによる扁平率に応じ
て、式(1)で与えられる数値が5〜11の範囲になる
ように、矯正ロールによる直径絞り率を調整する請求項
1記載の真円度の優れた溶接管の製造方法。 扁平率(%)+10×直径絞り率(%)・・・・(1)
3. The perfect circle according to claim 1, wherein the reduction ratio of the diameter by the straightening roll is adjusted so that the numerical value given by the expression (1) is in the range of 5 to 11 according to the flatness by the overbend roll. Manufacturing method of welded pipe with excellent degree. Flatness rate (%) + 10 × diameter drawing rate (%) ... (1)
JP06276297A 1997-03-17 1997-03-17 Manufacturing method of welded pipe with excellent roundness Expired - Fee Related JP3990761B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP06276297A JP3990761B2 (en) 1997-03-17 1997-03-17 Manufacturing method of welded pipe with excellent roundness

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP06276297A JP3990761B2 (en) 1997-03-17 1997-03-17 Manufacturing method of welded pipe with excellent roundness

Publications (2)

Publication Number Publication Date
JPH10258312A true JPH10258312A (en) 1998-09-29
JP3990761B2 JP3990761B2 (en) 2007-10-17

Family

ID=13209734

Family Applications (1)

Application Number Title Priority Date Filing Date
JP06276297A Expired - Fee Related JP3990761B2 (en) 1997-03-17 1997-03-17 Manufacturing method of welded pipe with excellent roundness

Country Status (1)

Country Link
JP (1) JP3990761B2 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100956830B1 (en) 2008-08-05 2010-05-07 주식회사 금강티더블유피 Metal pipe forming device
KR101313805B1 (en) * 2011-04-07 2013-10-01 오형동 Manufacturing method and apparatus for aluminum tube
CN108188202A (en) * 2017-12-29 2018-06-22 合肥实华管件有限责任公司 A kind of shaping device of plate welded tube and concetrated pipe
CN114273447A (en) * 2021-11-23 2022-04-05 杰森能源技术有限公司 Method for manufacturing metal pipe

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100956830B1 (en) 2008-08-05 2010-05-07 주식회사 금강티더블유피 Metal pipe forming device
KR101313805B1 (en) * 2011-04-07 2013-10-01 오형동 Manufacturing method and apparatus for aluminum tube
CN108188202A (en) * 2017-12-29 2018-06-22 合肥实华管件有限责任公司 A kind of shaping device of plate welded tube and concetrated pipe
CN114273447A (en) * 2021-11-23 2022-04-05 杰森能源技术有限公司 Method for manufacturing metal pipe

Also Published As

Publication number Publication date
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