JPH04313471A - Manufacture of forge welded steel tube - Google Patents

Manufacture of forge welded steel tube

Info

Publication number
JPH04313471A
JPH04313471A JP9637091A JP9637091A JPH04313471A JP H04313471 A JPH04313471 A JP H04313471A JP 9637091 A JP9637091 A JP 9637091A JP 9637091 A JP9637091 A JP 9637091A JP H04313471 A JPH04313471 A JP H04313471A
Authority
JP
Japan
Prior art keywords
edge
forge
skelp
cutting
welded steel
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.)
Pending
Application number
JP9637091A
Other languages
Japanese (ja)
Inventor
Mikio Odaka
小高 幹雄
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
Kawasaki Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kawasaki Steel Corp filed Critical Kawasaki Steel Corp
Priority to JP9637091A priority Critical patent/JPH04313471A/en
Publication of JPH04313471A publication Critical patent/JPH04313471A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE:To stably cut the skelp edge even immediately before forge welding, and to manufacture the forge welded steel tube having a weld zone being sound and having high strength. CONSTITUTION:An edge of a skelp S is subjected to roll forming into a prescribed shape, and thereafter, the skelp concerned S is preheated by a preheating furnace, and subsequently, the edge after roll forming is cut and formed, and thereafter, heated in a non-oxidizing atmosphere, the skelp S is formed to a tubular shape, and thereafter, the edge which is cut and formed is butted and forge welded, and a steel tube is manufactured.

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、鍛接鋼管の製造方法、
特に、鍛接前に熱間においてスケルプエッジを安定して
切削し、鍛接鋼管の鍛接強度を向上させることができる
鍛接鋼管の製造方法に関する。
[Industrial Application Field] The present invention relates to a method for manufacturing forge-welded steel pipes,
In particular, the present invention relates to a method for producing a forge-welded steel pipe that can stably cut the scalp edge in a hot state before forge-welding and improve the forge-weld strength of the forge-welded steel pipe.

【0002】0002

【従来の技術】鍛接鋼管は、スケルプを、例えば130
0℃くらいに加熱して管状に成形した後、その突合せ部
を鍛接ロールで加圧・溶接して製造される。
[Prior Art] Forge welded steel pipes have a skeleton of, for example, 130
It is manufactured by heating it to about 0°C and forming it into a tubular shape, and then pressurizing and welding the butted parts with a forge welding roll.

【0003】上記鍛接鋼管は、電縫鋼管に比較し、溶接
前の熱処理が長いため、表面が酸化されてスケールが発
生し易く、又、発生したスケールに対するアップセット
による排出効果がない等の理由により、その溶接(鍛接
)時にはスケールを巻込み易いために、鍛接鋼管の溶接
部には健全性・強度に大きなばらつきが生じていた。
[0003] Compared to electric resistance welded steel pipes, the forge welded steel pipes undergo a longer heat treatment before welding, so the surface is more likely to be oxidized and scale is generated, and there is no effect of upsetting the generated scale to remove it. As a result, it is easy to get scale involved during welding (forge welding), resulting in large variations in soundness and strength in the welded parts of forge welded steel pipes.

【0004】このように溶接部の健全性・強度のばらつ
きが生じることを防止するために、以下のような種々の
技術が提案されている。
[0004] In order to prevent such variations in the soundness and strength of welded parts, the following various techniques have been proposed.

【0005】(1)スケルプエッジの成形スケルプの突
合せエッジを成形ロールで所定形状に成形する技術が、
例えば、特公昭46−40762、特公昭49−332
59に提案されている。
(1) Forming of Skelp Edges There is a technique for forming the abutting edges of skelps into a predetermined shape using forming rolls.
For example, Special Publication No. 46-40762, Special Publication No. 49-332
59 has been proposed.

【0006】図4(A)に示すように、スケルプSのエ
ッジが未成形の場合には、図4(B)に示すように、ス
ケルプSの突合せ部にV字形状の隙間が生じるため、鍛
接後は、図4(C)に示すように、鍛接管Pの外側にV
字形の外面ノッチNが生じ、該ノッチNを基点にして割
れが発生し易いという欠点があった。しかし、上記エッ
ジ成形によれば、図5(A)に示すように、成形ロール
Rで所定傾斜角にスケルプの両エッジを成形するため、
管状に成形した場合には図5(B)に示すように突合せ
部を一致させることができるため、上記欠点が解消され
、しかも鍛接前に行う清浄化ブローによりスケールをパ
ージし易く、更に鍛接時には酸化物が拡散し易いため、
溶接強度を向上できるという利点がある。
[0006] As shown in FIG. 4(A), when the edge of the scalp S is not formed, a V-shaped gap is created at the abutting part of the scalp S, as shown in FIG. 4(B). After forge welding, as shown in Fig. 4(C), a V is formed on the outside of the forge welded pipe P.
There was a drawback that a letter-shaped outer surface notch N was formed, and cracks were likely to occur from the notch N as a starting point. However, according to the edge forming described above, as shown in FIG.
When formed into a tubular shape, the abutting parts can be aligned as shown in Figure 5(B), which eliminates the above disadvantages, and makes it easier to purge scale by cleaning blow before forge welding. Because oxides are easy to diffuse,
This has the advantage of improving welding strength.

【0007】(2)スケルプエッジの冷間切削このスケ
ルプエッジ冷間切削は、前記(1)のスケルプエッジの
成形に比べ、スリットエッジ面の不良部を切削除去する
ため、エッジ面を平滑化することができ、しかも切削す
るためにエッジを理想的な突合せ形状にすることができ
る利点がある。
(2) Cold cutting of the slit edge Compared to the above-mentioned (1) shaping of the slit edge, this cold cutting of the slit edge removes defective parts on the slit edge surface, making it possible to smooth the edge surface. Moreover, there is an advantage that the edges can be formed into an ideal butt shape for cutting.

【0008】(3)スケルプエッジの熱間切削このスケ
ルプエッジの熱間切削としては、特開昭61−1269
85に提案されている、鍛接直前に両エッジをバイト切
削する技術が知られている。
(3) Hot cutting of scalp edges This method of hot cutting of scalp edges is described in Japanese Patent Application Laid-Open No. 61-1269.
85, in which both edges are cut with a cutting tool immediately before forge welding is known.

【0009】上記公報記載の技術は、図6に示すように
、鍛接直前のスケルプSを、バイトBでエッジ切削を実
施するので、スリット不良、搬送中のエッジダメージ及
び加熱によるスケール等のエッジ不良を切削除去できる
。従って、鍛接後の溶接部の健全性をほぼ完全にするこ
とができ、しかも鍛接前のエッジを理想的な形状にする
ことができる利点もある。
[0009] As shown in FIG. 6, the technique described in the above publication performs edge cutting of the Skelp S immediately before forge welding with a bite B, so that edge defects such as slitting defects, edge damage during transportation, and scale due to heating are avoided. can be removed by cutting. Therefore, there is an advantage that the soundness of the welded part after forge welding can be almost perfected, and that the edge before forge welding can be made into an ideal shape.

【0010】(4)熱間ERW この熱間ERW(電縫管)は、鍛接管と電縫管の製法を
組合せた造管方法であり、図7に示すように、予熱室1
0で予熱したスケルプSを加熱室12で920℃の低温
(通常1300〜1450℃に加熱)に加熱した後、イ
ンダクションコイル14によるエッジ加熱を実施し、溶
接する。
(4) Hot ERW This hot ERW (ERW) is a pipe manufacturing method that combines the manufacturing methods of forge welded pipes and ERW pipes, and as shown in FIG.
After heating the Skelp S preheated at 0° C. to a low temperature of 920° C. (usually heated to 1300 to 1450° C.) in the heating chamber 12, edge heating is performed by the induction coil 14 and welding is performed.

【0011】その際、アップセットを大きくかけて、溶
接部の酸化物を排出させると共に、その際に形成される
排出ビードを切削する。
[0011] At this time, a large upset is applied to discharge the oxides from the welded portion, and at the same time, the discharge bead formed at that time is cut.

【0012】この熱間ERWは、電縫管と同様に酸化物
等の有害物を溶接時にアップセットにより内外ビードへ
排出させることができるため、前工程の影響を受け難く
、最終の溶接工程で溶接の健全性を図ることができる利
点がある。
Similar to electric resistance welding pipes, this hot ERW can discharge harmful substances such as oxides to the inner and outer beads by upsetting during welding, so it is less susceptible to the effects of the previous process and can be removed in the final welding process. This has the advantage of ensuring the soundness of welding.

【0013】[0013]

【発明が解決しようとする課題】従来の前記各技術には
、以下の問題点がある。
[Problems to be Solved by the Invention] Each of the above-mentioned conventional techniques has the following problems.

【0014】前記(1)のスケルプエッジの成形は、ス
リットエッジ面が図8(A)のダレDや、同図(B)の
ように、側方に突出したタングT等のように形状不良が
大きい場合は、その不良部を成形ロールで押込むことに
なるため、健全性や強度の改善効果はほとんどない。 又、上記不良部がない場合でも、エッジ成形は一般に冷
間で実施されているため、その後、スケルプを搬送する
際に発生するエッジダメージに対しては有効な対策とな
っていない。
[0014] The molding of the scalp edge described in (1) above prevents the slit edge surface from having shape defects such as the sagging D shown in FIG. If it is large, the defective part will be pressed in with a forming roll, and there will be little effect on improving the soundness or strength. Further, even if there is no defective portion, since edge forming is generally performed cold, there is no effective countermeasure against edge damage that occurs when the skelp is subsequently transported.

【0015】又、ロール成形を熱間で実施する場合は、
加工量が微小で且つ搬送速度が大きい(例えば、100
m /分以上)ので制御が困難であり、且つ、既に発生
したスケールをエッジに押込むことになり、逆効果とな
ることがある。
[0015] Furthermore, when roll forming is carried out hot,
The processing amount is small and the conveyance speed is high (for example, 100
m 2 /min or more), it is difficult to control, and the scale that has already occurred is forced into the edge, which may have the opposite effect.

【0016】更に、ロール成形では、必ずしも鍛接に都
合の良い形状にすることができるとは限らない。
Furthermore, roll forming does not necessarily make it possible to form a shape suitable for forge welding.

【0017】前記(2)スケルプエッジ冷間切削は、切
削量は微小で且つ、スリットエッジ面に応じて切削方向
を変化させなければならないが、スケルプの幅の変化や
曲り等に対する追従が困難であるため、切削制御が難し
く、人手によって制御しているのが実状である。
[0017] In (2) scalp edge cold cutting, the amount of cutting is minute and the cutting direction must be changed according to the slit edge surface, but it is difficult to follow changes in the width of the scalp, bends, etc. Therefore, cutting control is difficult, and the actual situation is that it is controlled manually.

【0018】又、スリットエッジ面の変化(例えば、後
述する図1(A)に示すようなバーアップ、バーダウン
)がある場合でも、切削形状を一定にするためには、切
削量を多く取らざるを得ず、そのため歩留りロスが大き
い。
Furthermore, even if there is a change in the slit edge surface (for example, bar-up or bar-down as shown in FIG. 1(A), which will be described later), in order to keep the cutting shape constant, the amount of cutting must be large. As a result, yield loss is large.

【0019】又、切削は冷間で実施するため、その後、
加熱等のためにスケルプを搬送する場合に発生するエッ
ジダメージに対しては有効な対策となっていない。
[0019] Furthermore, since the cutting is carried out cold,
There is no effective countermeasure against edge damage that occurs when skelp is transported for heating or the like.

【0020】更に、鍛接鋼管は、スケルプを長手方向に
つないで連続的に送って製造されるが、該スケルプの長
手方向の継ぎ部は切削負荷の変動が大きいため、切削バ
イトを保護する観点から該バイトを上記継ぎ部で逃がす
必要がある。そのため、上記継ぎ部前後に未切削部が残
ることになる。
Furthermore, forge-welded steel pipes are manufactured by connecting skelps in the longitudinal direction and feeding them continuously, but since the longitudinal joints of the skelps are subject to large fluctuations in cutting load, it is necessary to protect the cutting tool from the viewpoint of protecting the cutting tool. It is necessary to release the bite at the joint. Therefore, uncut portions remain before and after the joint portion.

【0021】前記(3)スケルプエッジの熱間切削は、
スケルプを丸めた後に、図6に示したように、狭いスペ
ースで且つ1200°以上の雰囲気の下で切削を行うた
め、設備設計が不可能に近く、仮にそれが可能であった
としても、熱間であるため安定した切削も困難であり、
設備寿命も極端に短い。
[0021] The above (3) hot cutting of the scalp edge is as follows:
As shown in Figure 6, after rounding the skelp, cutting is carried out in a narrow space and in an atmosphere of over 1200°, making it nearly impossible to design the equipment, and even if it were possible, the heat Stable cutting is also difficult due to the
Equipment life is also extremely short.

【0022】前記(4)熱間ERWは、内外面ビードを
切削する必要があるため、製造コストが高くなる。
[0022] In the hot ERW (4), since it is necessary to cut the inner and outer beads, the manufacturing cost becomes high.

【0023】又、低温加熱と言っても、冷間の電縫管に
比べて大量のスケールが存在する状況で溶接を実施して
いるので、図9に示すように、インダクションコイル1
4により発生し、エッジ部に優先的に流れる誘導電流i
 が、スケールSc が存在すると短絡するため、溶接
不良となる可能性が高い。それ故に、スポット的な溶接
不良部は逆に発生し易いと言える。
Furthermore, even though it is called low temperature heating, since welding is carried out in a situation where there is a large amount of scale compared to a cold electric resistance welded pipe, as shown in FIG. 9, the induction coil 1
The induced current i generated by 4 and flowing preferentially to the edge portion
However, if scale Sc exists, it will cause a short circuit, and there is a high possibility that welding will be defective. Therefore, it can be said that spot welding defects are more likely to occur.

【0024】以上詳述した従来の技術が抱える問題点を
要約すると、以下のようになる。
The problems faced by the conventional techniques detailed above can be summarized as follows.

【0025】スケルプの切削は、可能な限り鍛接を実施
する直前で行うことが、健全で高強度の溶接部を形成す
る上で最良の方法であるが、切削前のエッジ形状が一定
でなく、且つ熱間で行うために安定した切削が困難であ
る。
[0025] The best way to form a sound and high-strength weld is to cut the scalp immediately before forge welding as much as possible, but the shape of the edge before cutting is not constant, In addition, stable cutting is difficult because it is performed hot.

【0026】本発明は、前記従来の問題点を解決するべ
くなされたもので、鍛接直前でも、即ち熱間でもスケル
プエッジを安定して切削することを可能とし、健全で且
つ強度の高い溶接部を形成できる鍛接鋼管の製造方法を
提供することを課題とする。
The present invention has been made to solve the above-mentioned conventional problems, and makes it possible to stably cut a scalp edge even immediately before forge welding, that is, even during hot welding, and to produce a healthy and strong welded part. An object of the present invention is to provide a method for manufacturing a forge-welded steel pipe that can be formed.

【0027】[0027]

【課題を解決するための手段】本発明は、スケルプの両
エッジを熱間切削した後、該スケルプを管状に折曲し、
上記エッジを鍛接する鍛接鋼管の製造方法において、ス
ケルプの両エッジを所定形状に成形した後、該両エッジ
を熱間切削すること鍛接することにより、前記課題を達
成したものである。
[Means for Solving the Problems] The present invention hot-cuts both edges of a skelp and then bends the skelp into a tubular shape.
In the method for manufacturing a forge-welded steel pipe in which edges are forge-welded, the above-mentioned object is achieved by forming both edges of the skeleton into a predetermined shape, and then hot cutting and forge-welding both edges.

【0028】本発明は、又は、前記鍛接鋼管の製造方法
において、両エッジを成形したスケルプを予備加熱した
後、該両エッジを熱間切削し、次いで、該スケルプを無
酸化雰囲気炉で加熱することにより、同様に前記課題を
達成したものである。
[0028] Alternatively, in the method for manufacturing a forge-welded steel pipe, the present invention includes preheating the skelp with both edges formed, hot cutting the skelp, and then heating the skelp in a non-oxidizing atmosphere furnace. By doing so, the above-mentioned problem has been achieved as well.

【0029】[0029]

【作用】本発明においては、スケルプの両エッジを所定
形状に成形した後、該スケルプの両エッジを熱間切削す
るので、一定の切削量で所定のエッジ形状にすることが
可能となり、しかも鍛接直前でも切削可能であるので、
エッジ面にスケールのない状態で両エッジを鍛接するこ
とが可能となり、その結果、極めて健全で且つ高強度の
溶接部を有する鍛接鋼管を製造することが可能となる。
[Operation] In the present invention, both edges of the skelp are formed into a predetermined shape, and then both edges of the skelp are hot-cut, so it is possible to form a predetermined edge shape with a constant amount of cutting. Since it can be cut even just before cutting,
It becomes possible to forge-weld both edges without scale on the edge surfaces, and as a result, it becomes possible to manufacture a forge-welded steel pipe having an extremely sound and high-strength welded part.

【0030】又、エッジを成形したスケルプを予備加熱
した後、スケルプエッジを熱間切削し、次いで、該スケ
ルプを無酸化雰囲気炉で加熱するので、切削後に本加熱
を行う場合でも切削後のスケルプエッジにスケールを生
じさせることなく、該スケルプエッジを鍛接することが
できるので、健全で且つ高強度の溶接部を更に確実に形
成することができる。
[0030] Furthermore, after preheating the skelp on which the edge has been formed, the skelp edge is hot-cut, and then the skelp is heated in a non-oxidizing atmosphere furnace. Since the scalp edges can be forged-welded without producing scale, a sound and high-strength weld can be more reliably formed.

【0031】[0031]

【実施例】以下、図面を参照して、本発明の実施例を詳
細に説明する。
Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

【0032】図1は、本発明に係る一実施例の鍛接鋼管
の製造方法における工程の概略を示す説明図、図2は、
本実施例に適用する鍛接鋼管の製造装置を示す概略構成
図である。なお、図1(D)には、スケルプを同図(A
)〜(C)に比較して縮少し且つ全体を示してある。
FIG. 1 is an explanatory diagram showing an outline of the steps in a method for manufacturing a forge-welded steel pipe according to an embodiment of the present invention, and FIG.
1 is a schematic configuration diagram showing a forge-welded steel pipe manufacturing apparatus applied to this example. In addition, in Figure 1 (D), the Skelp is shown in the same figure (A
) to (C) and are shown in their entirety.

【0033】上記製造装置は、スケルプSを冷間でエッ
ジ成形するための成形ロール20と、該スケルプSを予
備加熱するための予熱炉22と、エッジ成形後のスケル
プのエッジを熱間切削する切削装置24と、エッジ切削
後のスケルプSを加熱する無酸化加熱炉26と、加熱後
のスケルプSのエッジを更に加熱するエッジヒータ28
と、エッジ加熱後のスケルプSを鍛接して鋼管Pを形成
する鍛接ロール30とを備えている。
The above manufacturing device includes a forming roll 20 for cold edge forming of the skelp S, a preheating furnace 22 for preheating the skelp S, and a hot cutting of the edge of the skelp after edge forming. A cutting device 24, a non-oxidizing heating furnace 26 that heats the Skelp S after edge cutting, and an edge heater 28 that further heats the edge of the Skelp S after heating.
and a forge welding roll 30 that forms a steel pipe P by forge welding the scalp S after edge heating.

【0034】上記無酸化加熱炉26では、バーナ32で
上記スケルプSを加熱するが、その際のバーナ32によ
る燃焼は、燃料に比べ酸素を不足した状態で行わせ、還
元性雰囲気になるようにしてあり、該加熱炉26の不完
全燃焼ガスは、前記予熱炉22へ供給され、該予熱炉2
2において完全燃焼するようになされている。
In the non-oxidizing heating furnace 26, the above-mentioned squelp S is heated by the burner 32, but the combustion by the burner 32 at this time is performed in a state in which oxygen is insufficient compared to the fuel, so that a reducing atmosphere is created. The incomplete combustion gas in the heating furnace 26 is supplied to the preheating furnace 22 and
2, complete combustion is achieved.

【0035】本実施例では、上記製造装置により、図1
(A)〜(D)に示す段階を経て鍛接鋼管を製造する。
In this example, the above-mentioned manufacturing apparatus was used to produce the image shown in FIG.
A forge-welded steel pipe is manufactured through the steps shown in (A) to (D).

【0036】まず、予熱炉22の前段に設置した成形ロ
ール20により、搬送されてくるスケルプSのエッジを
成形する。このエッジ成形は、図1(B)に示すように
、エッジ面が第1面(成管後外側になる面)S1に方線
に対して外側方向に−1〜7°、好ましくは0〜5°の
傾斜面となるように行われる。
First, the edge of the transported Skelp S is formed by the forming roll 20 installed at the front stage of the preheating furnace 22. In this edge forming, as shown in FIG. 1(B), the edge surface is directed outward from the normal to the first surface S1 (the surface that becomes the outside after tube formation) by -1 to 7 degrees, preferably 0 to 7 degrees. This is done so that the surface is inclined at 5°.

【0037】上記エッジ形成により、図1(A)に示す
ように、スケルプSが、ダレDが下にくるバーダウンで
も、又は上にくるバーアップでも、更には、タング等の
他のエッジ不良を有している場合でも、常に一定のエッ
ジ形状を形成できる。
As a result of the edge formation described above, as shown in FIG. A constant edge shape can always be formed even when the

【0038】次いで、エッジ形成を行ったスケルプSを
、予熱炉22で予備加熱した後、無酸化加熱炉26の全
段に設置した切削装置24により、図1(B)に示す成
形後のエッジを、熱間切削して同図(C)に示すように
斜線部分を切削除去し、切削エッジを形成する。このエ
ッジの熱間切削では、例えば700℃に加熱されたスケ
ルプSについて、切削エッジ面が第1面S1 の方線に
対して内側方向に、例えば7°の傾斜を有するように切
削する。なお、この傾斜角は、鋼管Pの径に応じて適宜
変更可能である。
Next, the edge-formed Skelp S is preheated in a preheating furnace 22, and then cut into edges after forming as shown in FIG. is hot cut to remove the diagonally shaded portion as shown in FIG. 5C to form a cutting edge. In this edge hot cutting, the scalp S heated to, for example, 700° C. is cut so that the cutting edge surface has an inclination of, for example, 7° inward with respect to the normal to the first surface S1. Note that this inclination angle can be changed as appropriate depending on the diameter of the steel pipe P.

【0039】この熱間切削の際には、前記エッジ成形に
よりスケルプSのエッジが一定の形状になっているため
、熱間でも安定した切削が可能となり、一定の切削量で
所定の形状に切削形成することができ、しかも最小の切
削量で適切な突合せ形状を形成することもできる。
[0039] During this hot cutting, since the edge of the Skelp S has a constant shape due to the edge forming, stable cutting is possible even during hot cutting, and the specified shape can be cut with a constant cutting amount. Moreover, an appropriate butt shape can be formed with a minimum amount of cutting.

【0040】上記熱間エッジ切削を行った後、スケルプ
Sは無酸化加熱炉26で、例えば1200℃に加熱され
、所定の管形状に成形され、次いで、更にエッジヒータ
28により切削形成された上記エッジが加熱され、その
後、鍛接ロール30により鍛接され、鋼管Pが形成され
る。
After the hot edge cutting described above, the Skelp S is heated to, for example, 1200° C. in a non-oxidizing heating furnace 26 and formed into a predetermined tube shape. The edges are heated and then forge welded by a forge welding roll 30 to form the steel pipe P.

【0041】上記無酸化加熱炉26による加熱では、無
酸化(還元)雰囲気で行われるてめ、切削形成されたエ
ッジ面にスケールが発生することが防止される。
Since heating in the non-oxidizing heating furnace 26 is performed in a non-oxidizing (reducing) atmosphere, it is possible to prevent scale from forming on the cut edge surface.

【0042】従って、本実施例によれば、清浄なエッジ
面で突合せ部を形成し、該突合せ部を鍛接することがで
きるため、健全で且つ高強度の溶接部を確実に形成する
ことができる。
Therefore, according to this embodiment, it is possible to form an abutting part with a clean edge surface and forge welding the abutting part, so that a sound and high-strength welded part can be reliably formed. .

【0043】又、スケルプSのエッジをロール形成した
後、熱間でエッジ切削を行うので、スケルプを長手方向
に連接している継ぎ部を切削する際でも切削負荷の変動
が小さいため、該継ぎ部前後でバイトを逃がして切削を
避ける必要がない。従って、未切削部を生じさせること
がないので、常に安定した品質の鍛接鋼管を製造できる
[0043] Furthermore, since the edges of the Skelp S are hot-cut after being rolled, the variation in cutting load is small even when cutting the joints connecting the Skelps in the longitudinal direction. There is no need to release the bite before and after the part to avoid cutting. Therefore, since no uncut portions are produced, forge-welded steel pipes of consistently stable quality can be manufactured.

【0044】又、予熱炉22は燃料を完全燃焼させるた
め酸化雰囲気であるため、上記熱間切削は該予熱炉22
の後段で行うことが合理的である。
Furthermore, since the preheating furnace 22 is in an oxidizing atmosphere to completely burn the fuel, the hot cutting is performed in the preheating furnace 22.
It is reasonable to do this at a later stage.

【0045】ここで、本実施例を適用して、SGP20
A及びSGP80Aの2種類の鍛接鋼管(本発明)を実
際に製造し、それを従来の方法によって製造した鍛接鋼
管(エッジ処理無、エッジ成形のみ)と、90°偏平値
及びET(渦電流探傷)不良発生率を求め、その結果を
下記表1及び表2に示した。
[0045] Here, by applying this embodiment, SGP20
Two types of forge welded steel pipes (the present invention), A and SGP80A, were actually produced, and then the forge welded steel pipes produced by the conventional method (no edge treatment, only edge forming), 90° flatness value and ET (eddy current testing) were produced. ) The defective incidence rate was determined and the results are shown in Tables 1 and 2 below.

【0046】[0046]

【表1】[Table 1]

【0047】[0047]

【表2】[Table 2]

【0048】ここで、90°偏平値とは、図3に示すよ
うに、溶接部Wを90°位置に配した状態で鋼管Pを上
下方向に同一の荷重で押圧した場合にシーム部にワレが
生ずるまでの上下方向の変形量で表わしたものである。 なお、各鍛接鋼管のサンプル数は100であり、90°
偏平地はその平均値である。又、σは標準偏差である。
Here, the 90° flattening value means, as shown in FIG. 3, when the steel pipe P is pressed vertically with the same load with the weld W placed at the 90° position, the seam cracks. It is expressed as the amount of vertical deformation until . The number of samples of each forge welded steel pipe was 100, and the angle was 90°.
Flat land is the average value. Moreover, σ is the standard deviation.

【0049】上記表1及び表2から、本実施例によれば
、極めて高い強度を有する溶接部を形成でき、本実施例
方法は極めて優れた鍛接鋼管の製造方法であることが分
かる。
From Tables 1 and 2 above, it can be seen that according to this example, a welded part with extremely high strength can be formed, and the method of this example is an extremely excellent method for manufacturing forge-welded steel pipes.

【0050】以上、本発明を具体的に説明したが、本発
明は、前記実施例に示したものに限られるものでなく、
その要旨を逸脱しない範囲で種々変更可能である。
Although the present invention has been specifically explained above, the present invention is not limited to what is shown in the above embodiments.
Various changes can be made without departing from the gist of the invention.

【0051】例えば、スケルプエッジのロール成形は、
実施例の冷間成形に限らず、熱間で行ってもよい。
For example, the roll forming of the scalp edge is
The cold forming is not limited to the embodiment, but hot forming may also be performed.

【0052】又、スケルプエッジの熱間切削は、無酸化
加熱炉の直前で行う場合に限らず、例えば鍛接直前で行
ってもよい。この場合は、スケルプの加熱を酸化雰囲気
炉で行う場合でも同様に高品質の鍛接鋼管を製造するこ
とができる。
Further, the hot cutting of the scalp edge is not limited to the case where it is performed immediately before the non-oxidizing heating furnace, but may be performed, for example, immediately before forge welding. In this case, even when the skelp is heated in an oxidizing atmosphere furnace, high-quality forge-welded steel pipes can be similarly produced.

【0053】[0053]

【発明の効果】以上説明した通り、本発明によれば、鍛
接直前でも、スケルプエッジを安定して熱間切削するこ
とができるので、健全で且つ強度の高い溶接部を有する
鍛接鋼管を製造することができる。
[Effects of the Invention] As explained above, according to the present invention, the scalp edges can be stably hot-cut even immediately before forge welding, so it is possible to manufacture forge welded steel pipes having sound and strong welded parts. Can be done.

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

【図1】図1は、本発明に係る一実施例の鍛接鋼管の製
造方法における工程の概略を示す説明図である。
FIG. 1 is an explanatory diagram showing an outline of steps in a method for manufacturing a forge-welded steel pipe according to an embodiment of the present invention.

【図2】図2は、本実施例に適用する鍛接鋼管の製造装
置を示す概略構成図である。
FIG. 2 is a schematic configuration diagram showing a forge-welded steel pipe manufacturing apparatus applied to this embodiment.

【図3】図3は、実施例における試験方法を示す概略説
明図である。
FIG. 3 is a schematic explanatory diagram showing a test method in an example.

【図4】図4は、従来の問題点を示す概略説明図である
FIG. 4 is a schematic explanatory diagram showing conventional problems.

【図5】図5は、スケルプエッジのロール成形を示す概
略説明図である。
FIG. 5 is a schematic explanatory diagram showing roll forming of a scalp edge.

【図6】図6は、従来のスケルプエッジの熱間切削の問
題点を示す概略説明図である。
FIG. 6 is a schematic explanatory diagram showing problems in conventional hot cutting of a scalp edge.

【図7】図7は、熱間ERWの製造装置を示す概略構成
図である。
FIG. 7 is a schematic configuration diagram showing a hot ERW manufacturing apparatus.

【図8】図8は、スケルプエッジの形状不良を示す概略
説明図である。
FIG. 8 is a schematic explanatory diagram showing a defective shape of a scalp edge.

【図9】図9は、熱間ERWの問題点を示す概略説明図
である。
FIG. 9 is a schematic explanatory diagram showing problems with hot ERW.

【符号の説明】[Explanation of symbols]

S…スケルプ、 20…成形ロール、 22…予熱炉、 24…切削装置、 26…無酸化加熱炉、 28…エッジヒータ、 30…鍛接ロール。 S...Skelp, 20...forming roll, 22... Preheating furnace, 24...Cutting device, 26...Non-oxidation heating furnace, 28...edge heater, 30...Forge welding roll.

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】スケルプの両エッジを熱間切削した後、該
スケルプを管状に折曲し、上記エッジを鍛接する鍛接鋼
管の製造方法において、スケルプの両エッジを所定形状
に成形した後、該両エッジを熱間切削することを特徴と
する鍛接鋼管の製造方法。
1. A method for manufacturing a forge-welded steel pipe, in which both edges of a skelp are hot-cut, the skelp is bent into a tubular shape, and the edges are forge-welded. A method for manufacturing a forge-welded steel pipe, characterized by hot cutting both edges.
【請求項2】請求項1において、両エッジを成形したス
ケルプを予備加熱した後、該両エッジを熱間切削し、次
いで、該スケルプを無酸化雰囲気炉で加熱することを特
徴とする鍛接鋼管の製造方法。
2. The forged welded steel pipe according to claim 1, wherein the skelp with both edges formed is preheated, then both edges are hot cut, and then the skelp is heated in a non-oxidizing atmosphere furnace. manufacturing method.
JP9637091A 1991-04-02 1991-04-02 Manufacture of forge welded steel tube Pending JPH04313471A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9637091A JPH04313471A (en) 1991-04-02 1991-04-02 Manufacture of forge welded steel tube

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9637091A JPH04313471A (en) 1991-04-02 1991-04-02 Manufacture of forge welded steel tube

Publications (1)

Publication Number Publication Date
JPH04313471A true JPH04313471A (en) 1992-11-05

Family

ID=14163086

Family Applications (1)

Application Number Title Priority Date Filing Date
JP9637091A Pending JPH04313471A (en) 1991-04-02 1991-04-02 Manufacture of forge welded steel tube

Country Status (1)

Country Link
JP (1) JPH04313471A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008161940A (en) * 2005-11-11 2008-07-17 Nippon Steel Corp Forge-welded steel pipe excellent in workability, method of manufacturing it and manufacturing equipment train

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008161940A (en) * 2005-11-11 2008-07-17 Nippon Steel Corp Forge-welded steel pipe excellent in workability, method of manufacturing it and manufacturing equipment train

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