JPH105856A - Manufacture of steel tube - Google Patents
Manufacture of steel tubeInfo
- Publication number
- JPH105856A JPH105856A JP16876396A JP16876396A JPH105856A JP H105856 A JPH105856 A JP H105856A JP 16876396 A JP16876396 A JP 16876396A JP 16876396 A JP16876396 A JP 16876396A JP H105856 A JPH105856 A JP H105856A
- Authority
- JP
- Japan
- Prior art keywords
- edge
- heating
- pipe
- preheating
- 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.)
- Granted
Links
Landscapes
- General Induction Heating (AREA)
- Pressure Welding/Diffusion-Bonding (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、鋼管の製造方法に
関し、とくに、固相圧接による鋼管の製造方法に関す
る。The present invention relates to a method for manufacturing a steel pipe, and more particularly, to a method for manufacturing a steel pipe by solid-state pressure welding.
【0002】[0002]
【従来の技術】溶接鋼管は、鋼板または鋼帯を管状に成
形しその継目を溶接したもので、小径から大径まで各種
の製造法によりつくられているが、主な製造法として、
電気抵抗溶接(電縫)、鍛接、電弧溶接によるものが挙
げられる。小径〜中径鋼管用としては、高周波誘導加熱
を利用した電気抵抗溶接法(電気抵抗溶接鋼管、電縫
管)が主として利用されている。この方法は、連続的に
帯鋼を供給し、成形ロールで管状に成形してオープン管
とし、続いて高周波誘導加熱によりオープン管の両エッ
ジ部端面を鋼の融点以上に加熱した後、スクイズロール
で両エッジ部端面を衝合溶接して鋼管を製造する方法で
ある(例えば、第3版鉄鋼便覧第III 巻(2)1056〜10
92頁)。2. Description of the Related Art Welded steel pipes are formed by forming a steel plate or a steel strip into a tube and welding the seams thereof, and are made by various manufacturing methods from a small diameter to a large diameter.
Examples include electric resistance welding (electric resistance welding), forge welding, and electric arc welding. For small to medium diameter steel pipes, an electric resistance welding method (electric resistance welded steel pipe, electric resistance welded pipe) utilizing high frequency induction heating is mainly used. In this method, a steel strip is continuously supplied, formed into a tubular shape with a forming roll to form an open pipe, and then the end faces of both edges of the open pipe are heated by high-frequency induction heating to a temperature equal to or higher than the melting point of the steel. (See, for example, the third edition of the Iron and Steel Handbook, Vol. III (2), 1056-10).
92).
【0003】上記した高周波誘導加熱を利用した電縫管
の製造方法では、オープン管の両エッジ部端面を鋼の融
点以上に加熱するため、電磁力の影響により溶鋼が流動
し、生成された酸化物が衝合溶接部に噛み込まれペネト
レータ等の溶接欠陥あるいは、溶鋼飛散(フラッシュ)
が発生しやすいという問題があった。この問題に対し、
例えば、特開平2-299782号公報には、2つの加熱装置を
有する電縫鋼管の製造法が提案されている。第1の加熱
装置でオープン管の両側エッジ部の温度をキュリー点以
上に加熱し、第2の加熱装置で更に融点以上に加熱し、
スクイズロールで両エッジ部を衝合溶接して鋼管を製造
する。また、特開平2-299783号公報には、第1の加熱装
置で周波数45〜250kHzの電流を流し、両側エッジ部を予
熱し、第2の加熱装置で更に融点以上に加熱し、スクイ
ズロールで両エッジ部を衝合溶接して鋼管を製造する電
縫管製造装置が提案されている。In the above-described method of manufacturing an electric resistance welded tube utilizing high frequency induction heating, since the end surfaces of both edges of the open tube are heated to the melting point of the steel or higher, the molten steel flows under the influence of electromagnetic force, and the generated oxidation occurs. An object is caught in the abutment weld and welding defects such as penetrators or molten steel scatter (flash)
There is a problem that is easy to occur. For this issue,
For example, Japanese Patent Application Laid-Open No. 2-299782 proposes a method for manufacturing an electric resistance welded steel pipe having two heating devices. The first heating device heats the temperature of both side edges of the open tube to the Curie point or higher, and the second heating device further heats to the melting point or higher.
A steel pipe is manufactured by butt welding both edges with a squeeze roll. Also, in Japanese Patent Application Laid-Open No. 2-299832, a current having a frequency of 45 to 250 kHz is passed by a first heating device to preheat both side edges, and further heated to a melting point or higher by a second heating device and squeezed by a squeeze roll. There has been proposed an electric resistance welded pipe manufacturing apparatus which manufactures a steel pipe by abutting both edges.
【0004】しかしながら、これらの電縫管製造技術で
は、エッジ部を均一に加熱することは示唆しているもの
の、両エッジ部を鋼の融点以上に加熱するため、衝合溶
接時に、溶融した鋼が管の内外面に排出されビード(余
盛)が形成される。そのため、衝合溶接後に管内外面の
溶接ビードの除去が必要であり、ほとんどがビード切削
用バイトにより切削されて除去されている。[0004] However, although these electric resistance welded pipe manufacturing techniques suggest that the edges are uniformly heated, since both edges are heated to the melting point of the steel or higher, the molten steel is hardened at the time of impact welding. Is discharged to the inner and outer surfaces of the tube to form a bead. Therefore, it is necessary to remove the weld bead on the inner and outer surfaces of the pipe after the impact welding, and most of the bead is removed by cutting with a bead cutting tool.
【0005】このようなことから、この方法では、 ビード切削用バイトの切削量の調整で、材料と時間の
ロスが発生する。 ビード切削用バイトは消耗品であるため、造管速度に
よって異なるが、3000〜4000mのビード切削長毎にバイ
トを交換する必要があり、そのため、1時間程度ごとに
3〜5分間のバイト交換のためのラインの停止を余儀な
くされる。[0005] For this reason, in this method, loss of material and time occurs due to adjustment of the cutting amount of the bead cutting tool. Since the bead cutting tool is a consumable, it needs to be changed every 3000-4000m bead cutting length, depending on the pipe forming speed. Therefore, it is necessary to change the bite for 3-5 minutes every hour. Forced to stop the line.
【0006】特に造管速度が100 m/min を超える高
速造管では、ビード切削用バイトの寿命が短く、交換頻
度が高い。など、ビード切削がネックとなり、高速造管
ができないため生産性が低いという問題があった。一
方、比較的小径鋼管用として極めて高い生産性を有する
鍛接鋼管製造方法がある。この方法は、連続的に供給し
た帯鋼を加熱炉で1300℃程度に加熱した後、成形ロール
で管状に成形してオープン管とし、続いてオープン管の
両エッジ部に高圧空気を吹き付けて端面のスケールオフ
を行った後、ウェルディングホーンにより端面に酸素を
吹き付け、その酸化熱で端面を1400℃程度に昇温させて
から、鍛接ロールで両エッジ部端面を衝合させ固相接合
して鋼管を製造する方法である(例えば、第3版鉄鋼便
覧第III 巻(2)1056〜1092頁)。In particular, in high-speed pipe forming in which the pipe forming speed exceeds 100 m / min, the life of the bead cutting tool is short and the frequency of replacement is high. There was a problem that bead cutting became a bottleneck and high-speed pipe making was not possible, resulting in low productivity. On the other hand, there is a method for producing a forged steel pipe having extremely high productivity for a relatively small diameter steel pipe. In this method, a continuously supplied steel strip is heated to about 1300 ° C in a heating furnace, and then formed into a tubular shape with a forming roll to form an open pipe. After performing the scale-off, oxygen is blown to the end face by the welding horn, and the end face is heated to about 1400 ° C. by the heat of oxidation, and then the end faces of both edges are abutted by a forging roll to perform solid-state joining. This is a method for producing a steel pipe (for example, Third Edition Iron and Steel Handbook, Vol. III (2), pp. 1056-1092).
【0007】しかし、この鍛接鋼管製造方法では、 端面のスケールオフが完全ではないので、鍛接衝合部
へのスケール噛込みが発生し、シーム部の強度が母材部
に比べてかなり劣る。このため、偏平試験で、電縫鋼管
なら偏平高さ比h/D=2t/D(t:板厚)を達成で
きるのに対し、鍛接鋼管では偏平高さ比h/Dが0.5 程
度に劣るものとなる。However, in this method for producing a forged steel pipe, the scale-off of the end face is not perfect, so that the scale is caught in the forged joint portion, and the strength of the seam portion is considerably inferior to that of the base material portion. For this reason, in the flattening test, the flattened height ratio h / D = 2t / D (t: plate thickness) can be achieved with an ERW steel pipe, while the flattened height ratio h / D is inferior to about 0.5 with a forged steel pipe. It will be.
【0008】帯鋼を高温に加熱するため、管表面にス
ケールが生成し表面肌が悪い。など、造管速度が300m/
min 以上と速く生産性は高いが、シーム品質及び表面肌
が悪く、JISのSTK等の強度信頼性や表面品質を要
求されるものは製造できないという問題があった。[0008] Since the steel strip is heated to a high temperature, scale is formed on the pipe surface, and the surface skin is poor. The pipe making speed is 300m /
Although the productivity is high as short as min or more, the seam quality and the surface skin are poor, and there is a problem that products requiring strength reliability and surface quality such as JIS STK cannot be manufactured.
【0009】[0009]
【発明が解決しようとする課題】本発明は、上記問題を
有利に解決し、優れたシーム品質及び表面肌を有する鋼
管を高い生産性で製造することができる、誘導加熱方式
による鋼管の製造方法を提案することを目的とする。DISCLOSURE OF THE INVENTION The present invention advantageously solves the above-mentioned problems, and enables a steel pipe having excellent seam quality and surface skin to be manufactured with high productivity. The purpose is to propose.
【0010】[0010]
【課題を解決するための手段】本発明は、帯鋼を成形ロ
ールにより連続的に成形してオープン管とし、該オープ
ン管の両エッジ部を加熱し、スクイズロールで衝合接合
する鋼管の製造方法において、両エッジ部の加熱に先立
って、前記オープン管、または前記帯鋼およびオープン
管を予熱し、これに続き前記オープン管の両エッジ部
に、誘導加熱によりキュリー点以上の温度に加熱するエ
ッジ予熱を施したのち、さらに、誘導加熱により1300℃
以上、融点未満の温度域に加熱するエッジ加熱を施し、
該スクイズロールで圧接することを特徴とするシーム品
質および表面肌の優れた鋼管の製造方法であり、前記エ
ッジ予熱は、キュリー点以上1300℃未満の温度に加熱す
るのが好ましく、また、前記オープン管の予熱、前記帯
鋼および前記オープン管の予熱は800 ℃以下の温度で行
うのが好ましい。また、前記エッジ予熱、前記エッジ加
熱および前記圧接は、大気より低い酸素濃度雰囲気中あ
るいは、露点が−10℃以下の雰囲気中で行うのが好まし
い。前記圧接後、接合部が1300℃以上に保持される時間
tk (sec )が、0.03sec 以上または次式(1) tk ≧a・exp{−b・〔O2 〕c } …… (1) (ここに、O2 :雰囲気中の酸素濃度(vol %)、a=
0.079 、b=1.5 、c=-0.14 )を満足するのが好適で
ある。SUMMARY OF THE INVENTION According to the present invention, a steel pipe is manufactured by continuously forming a strip from a forming roll into an open pipe, heating both edges of the open pipe, and abutting and joining with a squeeze roll. In the method, prior to heating both edges, the open pipe, or the strip and the open pipe, are preheated, and then both edges of the open pipe are heated to a temperature above the Curie point by induction heating. After edge preheating, 1300 ° C by induction heating
Above, subjected to edge heating to heat the temperature range below the melting point,
A method for producing a steel pipe having excellent seam quality and surface texture characterized by being pressed against the squeeze roll, wherein the edge preheating is preferably performed by heating to a temperature equal to or higher than the Curie point and lower than 1300 ° C. Preferably, the preheating of the pipe, the preheating of the strip and the open pipe is carried out at a temperature below 800 ° C. The edge preheating, the edge heating, and the pressure welding are preferably performed in an oxygen concentration atmosphere lower than the atmosphere or in an atmosphere having a dew point of −10 ° C. or less. After the pressure contact, the time t k which joint is held above 1300 ° C. (sec) is, 0.03sec more or the following formula (1) t k ≧ a · exp {-b · [O 2] c} ...... ( 1) (where, O 2 : oxygen concentration in the atmosphere (vol%), a =
0.079, b = 1.5, c = -0.14).
【0011】また、本発明では、前記圧接時に、管内外
からシーム部管材を拘束し、シーム部増肉を抑制しても
よい。また、本発明では、前記圧接後、圧接シーム部近
傍を圧延してもよい。また、本発明では、前記圧接後、
圧接シーム部外面の微小凹形状部を除去して外面を平滑
化してもよい。Further, in the present invention, at the time of the pressing, the seam portion pipe may be restrained from inside and outside of the tube to suppress the increase in the thickness of the seam portion. Further, in the present invention, after the pressing, the vicinity of the pressing seam portion may be rolled. Further, in the present invention, after the pressing,
The outer surface may be smoothed by removing a minute concave portion on the outer surface of the press-seam portion.
【0012】また、前記帯鋼は、エッジ部端面を平坦化
し、該エッジ部端面と該帯鋼表面とのなす角度が所定の
角度とするエッジ処理を施されたものが好ましい。さら
に、前記帯鋼端面のエッジ処理は成形ロールによる成形
前または成形後行ってもよい。It is preferable that the strip steel has been subjected to an edge treatment in which an end face of the edge portion is flattened and an angle formed between the end face of the edge portion and the surface of the strip steel is a predetermined angle. Further, the edge treatment of the end face of the steel strip may be performed before or after forming by a forming roll.
【0013】[0013]
【発明の実施の形態】帯鋼は、成形ロールにより連続的
に成形されオープン管となる。成形は通常公知の成形ロ
ールによる方法が好適に適用できる。本発明では、成形
後のオープン管を予熱する。また、帯鋼の成形に先立っ
て帯鋼を予熱しさらに成形後のオープン管を予熱しても
よい。BEST MODE FOR CARRYING OUT THE INVENTION A strip is continuously formed by a forming roll into an open pipe. For molding, a known method using a molding roll can be suitably applied. In the present invention, the open pipe after molding is preheated. Further, the strip may be preheated before the strip is formed, and the open pipe after the forming may be preheated.
【0014】予熱は、後に行うエッジ加熱時にエッジ部
とその近傍の母管との温度差を小さくし、固相圧接段階
において、エッジ部の温度および温度分布を固相圧接可
能温度域に容易に維持できるようにするために行う。予
熱は、加熱炉を用いる方法、誘導コイルを用いる誘導加
熱方法、通電による抵抗加熱方法いずれも好適に適用で
きる。In the preheating, the temperature difference between the edge portion and the mother pipe near the edge portion is reduced during edge heating performed later, and the temperature and temperature distribution of the edge portion are easily adjusted to a temperature range where solid phase pressure welding is possible in the solid phase pressure welding stage. Do it so you can maintain it. As the preheating, any of a method using a heating furnace, an induction heating method using an induction coil, and a resistance heating method using current can be suitably applied.
【0015】予熱温度は、帯鋼の場合もオープン管の場
合も、800 ℃以下の温度範囲とする。帯鋼およびオープ
ン管を予熱する場合には、帯鋼の予熱を成形装置への熱
負荷が低くかつ成形加工に適した温度にし、オープン管
の予熱をさらに高い温度とする2段階予熱が好ましい。
800 ℃を超える予熱は、接合すべきエッジ部を含む管体
全面に多量のスケールが生成し、鋼管のシーム品質およ
び表面肌がともに劣化するため、800 ℃を予熱温度の上
限とした。なお、予熱温度が400 ℃未満では、エッジ加
熱時に、エッジ部から母管側への熱拡散が多いため、圧
接時のエッジ部温度及び温度分布を固相圧接可能温度域
に維持できにくく、また、予熱温度が 650℃を超える
と、オープン管表面のスケールが生成しやすくなり、こ
のため、予熱温度は、400 〜 650℃の温度範囲とするの
が好適である。The preheating temperature is set to a temperature range of 800 ° C. or less for both the steel strip and the open pipe. When preheating the steel strip and the open pipe, two-stage preheating is preferably performed in which the preheating of the steel strip is performed at a temperature at which the heat load on the forming apparatus is low and suitable for forming, and the preheating of the open pipe is further increased.
If the preheating exceeds 800 ° C., a large amount of scale is formed on the entire surface of the pipe including the edges to be joined, and the seam quality and surface skin of the steel pipe are deteriorated. Therefore, the upper limit of the preheating temperature is set to 800 ° C. If the preheating temperature is less than 400 ° C., the edge temperature and the temperature distribution during pressure welding cannot be maintained in the temperature range where solid-state pressure welding is possible, since there is much heat diffusion from the edge to the mother pipe side during edge heating. If the preheating temperature exceeds 650 ° C., scale on the surface of the open tube is easily generated, and therefore, the preheating temperature is preferably set to a temperature range of 400 to 650 ° C.
【0016】ついで、オープン管の両エッジ部をエッジ
予熱する。エッジ予熱は、誘導加熱方式とする。このエ
ッジ予熱によりエッジ部の温度を、キュリー点以上、好
ましくは1300℃未満とする。図7に示す鋼の比透磁率の
温度依存性から、鋼をキュリー点以上に加熱すると鋼は
強磁性体から常磁性体へ磁気変態し、比透磁率(対真空
比)が1に近い値となる。一方、誘導電流の浸透深さS
は、次式(2)で与えられる。Next, both edges of the open tube are edge preheated. Edge preheating is performed by an induction heating method. By this edge preheating, the temperature of the edge portion is set to the Curie point or higher, preferably lower than 1300 ° C. From the temperature dependence of the relative magnetic permeability of the steel shown in FIG. 7, when the steel is heated above the Curie point, the steel undergoes magnetic transformation from a ferromagnetic material to a paramagnetic material, and the relative magnetic permeability (vs. vacuum ratio) is close to 1. Becomes On the other hand, the induced current penetration depth S
Is given by the following equation (2).
【0017】 S=α{ρ/(μr f)}1/2 ……(2) ここに、S:浸透深さ(m)、ρ:抵抗率(Ω・m)、
μr :比透磁率、f:周波数(kHz )、α:定数であ
る。したがって、エッジ部をキュリー点以上に加熱する
ことにより、浸透深さSが大きくなり、被圧接面内の温
度分布が均一化する方向に向かう。そこで、キュリー点
以上の温度域にエッジ部を予熱するのである。加熱エネ
ルギー効率の観点からは、キュリー点以上1300℃未満の
温度で行うのが好ましいが、1300℃以上としても何ら不
都合はない。しかし、この段階で一気に昇温すると、角
部のみが融点以上になり、接合時にビード(余盛)が発
生するため、高速造管ができなくなる場合があり、エッ
ジ予熱は、キュリー点以上1300℃未満の温度域で行うの
が好ましい。S = α {ρ / (μ rf )} 1/2 (2) where, S: penetration depth (m), ρ: resistivity (Ω · m),
μ r: relative permeability, f: Frequency (kHz), α: a constant. Therefore, by heating the edge portion to a temperature higher than the Curie point, the penetration depth S is increased, and the temperature distribution in the pressure contact surface is directed to be uniform. Therefore, the edge portion is preheated to a temperature range higher than the Curie point. From the viewpoint of heating energy efficiency, the heating is preferably performed at a temperature equal to or higher than the Curie point and lower than 1300 ° C., but there is no inconvenience even if the temperature is higher than 1300 ° C. However, if the temperature rises at this stage, only the corners become higher than the melting point, and beads (surplus) are generated at the time of joining, so that high-speed pipe forming may not be possible. It is preferable to carry out in a temperature range of less than.
【0018】エッジ予熱は、大気中あるいは、大気中よ
り酸素濃度を低減された雰囲気中(シールド雰囲気中)
いずれでもよいが、シーム品質の点からはシールド雰囲
気中が好ましい。また、エッジ予熱は、露点が−10℃以
下の雰囲気中で行うのが好ましい。エッジ予熱を施され
たオープン管の両エッジ部は、さらに、1300℃以上、融
点未満の温度域に加熱するエッジ加熱が施される。The edge preheating is performed in the atmosphere or in an atmosphere in which the oxygen concentration is lower than that in the atmosphere (in a shield atmosphere).
Either one may be used, but from the point of seam quality, it is preferable to be in a shield atmosphere. The edge preheating is preferably performed in an atmosphere having a dew point of −10 ° C. or less. Both edge portions of the open tube subjected to the edge preheating are further subjected to edge heating for heating to a temperature range of 1300 ° C. or higher and lower than the melting point.
【0019】エッジ加熱の加熱方式は、エネルギー効率
の観点から、誘導コイルによる誘導加熱方式とする。エ
ッジ加熱は、加熱効率の観点からオープン管内に適当な
大きさのインピーダを配設するのが好ましいが、インピ
ーダの大きさを小さくした場合あるいはインピーダを配
置しない場合でもエッジ加熱は可能である。この場合
は、エッジ部以外の管体も加熱されやすくなる。The heating method of the edge heating is an induction heating method using an induction coil from the viewpoint of energy efficiency. For the edge heating, it is preferable to dispose an appropriate size of the impeder in the open tube from the viewpoint of the heating efficiency, but the edge heating can be performed even when the size of the impeder is reduced or the impeder is not arranged. In this case, the tube body other than the edge portion is also easily heated.
【0020】オープン管の両エッジ部端面の温度は、誘
導加熱コイルの出力の調整により制御する。エッジ加熱
の温度が1300℃未満では、エッジ部端面の接合が不十分
となりシーム品質が劣化する。また、エッジ部端面の温
度が管材の融点を超えると、溶融した鋼が衝合接合時に
管内外にビード(余盛)を形成するため、ビード切削を
必要とする。このことからエッジ加熱は1300℃以上、融
点未満の固相圧接可能温度域とする。なお、好ましくは
1350℃以上融点未満、より好ましくは1400℃以上融点未
満である。The temperature at the end surfaces of both edges of the open tube is controlled by adjusting the output of the induction heating coil. If the temperature of the edge heating is lower than 1300 ° C., the joining of the end face of the edge portion becomes insufficient and the seam quality is deteriorated. Further, if the temperature of the end face of the edge portion exceeds the melting point of the pipe material, the molten steel forms beads (extra-bulb) inside and outside the pipe at the time of abutment joining, so that bead cutting is required. For this reason, the edge heating is performed in a temperature range of 1300 ° C. or higher and lower than the melting point where solid-state pressure welding can be performed. Preferably,
It is 1350 ° C. or higher and lower than the melting point, more preferably 1400 ° C. or higher and lower than the melting point.
【0021】本発明でいう固相圧接とは、ビード(余
盛)の盛り上がりを抑え、ビード切削を必要としない圧
接を意味する。本発明では、ビード(余盛)の盛り上が
り量を抑制するため、エッジ加熱温度は固相域の温度が
好ましいが、若干の液相が存在する融点未満の固液2相
域でも何ら不都合はない。The solid-phase pressure welding referred to in the present invention means a pressure welding in which bead (surplus) swelling is suppressed and bead cutting is not required. In the present invention, the edge heating temperature is preferably the temperature in the solid phase region in order to suppress the amount of bead (surplus) swelling, but there is no inconvenience even in the solid-liquid two-phase region below the melting point where some liquid phase exists. .
【0022】誘導加熱時のエッジ部の温度分布を均一に
するために、本発明では、好ましくは、帯鋼のエッジだ
れを精整し、エッジ部端面を平坦化し、エッジ部端面と
帯鋼表面のなす角度が所定の角度とするのがよい。所定
の角度は60〜120 度が好ましい。このエッジだれの精整
は、コイルをペイオフする前あるいは、コイルをペイオ
フし成形ロールでオープン管に成形する前、あるいは成
形した後いずれで行ってもよい。エッジ処理は、エッジ
ミラーによる切削、グラインダによる研磨、またはエッ
ジャーロールによる圧延加工等により行うのが好まし
い。In order to make the temperature distribution of the edge portion at the time of induction heating uniform, in the present invention, preferably, the edge of the steel strip is refined, the edge face is flattened, and the edge face and the steel strip surface are preferably flattened. Is preferably a predetermined angle. The predetermined angle is preferably 60 to 120 degrees. The edge shaping may be performed before the coil is paid off, before the coil is paid off and formed into an open pipe by a forming roll, or after the coil is formed. The edge treatment is preferably performed by cutting with an edge mirror, polishing with a grinder, rolling with an edger roll, or the like.
【0023】両エッジ部を上記固相圧接可能温度域に加
熱されたオープン管は、スクイズロールで両エッジ部を
衝合され、固相圧接される。圧接は、図3(a)に示す
ように、スクイズロールを圧接接合部管外面に当接する
位置に設置して行う方法と、図3(b)に示すように、
スクイズロールを圧接接合部管外面に当接しない位置に
設置して行う方法および図3(c)に示すように、外面
側はスクイズロール、内面側はロール等を圧接接合部に
当接する位置に設置して行う方法があるが、いずれの場
合でも何ら不都合は生じない。The open pipe whose both edge portions are heated to the above-mentioned solid-state pressure-contactable temperature range is abutted on both edge portions by a squeeze roll and solid-phase pressed. As shown in FIG. 3 (a), the pressure welding is performed by setting a squeeze roll at a position where the squeeze roll is in contact with the outer surface of the pressure-welded joint pipe, and as shown in FIG. 3 (b),
As shown in FIG. 3 (c), a method in which a squeeze roll is installed at a position where the squeeze roll does not abut against the outer surface of the press-joined portion and the outer surface side is at a position where the squeeze roll is in contact with the press-joined portion. There is a method of installing and performing, but in any case, no inconvenience occurs.
【0024】エッジ加熱および固相圧接は、大気中ある
いは、大気中より酸素濃度を低減された雰囲気中(シー
ルド雰囲気中)いずれでもよいが、シーム品質の点から
はシールド雰囲気中が好ましい。また、エッジ加熱およ
び固相圧接は、シーム品質の点から、露点が−10℃以下
の雰囲気中で行うのが好ましい。本発明者らは、圧接
後、接合部が1300℃以上に保持される時間tk により、
鋼管のシーム品質が変化することを見いだした。シーム
品質(偏平高さ比h/D)に及ぼすtk と、酸素濃度の
関係を図2に示す。図2から、tk が長くなるにしたが
い、シーム品質が向上していることがわかる。また、雰
囲気中の酸素濃度が低減するにしたがい、同一シーム品
質を得るためにはtk は短くしてもよいことがわかる。The edge heating and the solid-state pressure welding may be performed in the air or in an atmosphere in which the oxygen concentration is lower than that in the air (in a shield atmosphere), but preferably in a shield atmosphere from the viewpoint of seam quality. Further, it is preferable that the edge heating and the solid-phase pressure welding are performed in an atmosphere having a dew point of −10 ° C. or less from the viewpoint of seam quality. The present inventors have found that after pressing, the time t k at which the joint is maintained at 1300 ° C. or higher is determined by
It was found that the seam quality of steel pipes changed. And t k on the seam quality (flat height ratio h / D), the relationship between the oxygen concentration shown in Fig. From Figure 2, t k in accordance becomes longer, it can be seen that the seam quality is improved. Further, in accordance with the oxygen concentration in the atmosphere is reduced, in order to obtain the same seam quality t k it is understood that it may be shortened.
【0025】この時間tk (sec )は、エッジ予熱、エ
ッジ加熱、固相圧接が大気中で行われた場合には、0.03
sec 以上とすることが好ましい。一方、エッジ予熱、エ
ッジ加熱、固相圧接が大気中より酸素濃度が低い雰囲気
(シールド雰囲気中)で行われた場合は、tk は、次式
(1)を満足する時間とすることが好ましい。 tk ≧a・exp{−b・〔O2 〕c } …… (1) ここに、O2 :雰囲気中の酸素濃度(vol %)、a、
b、c:定数で、低炭素鋼の場合a=0.079 、b=1.5
、c=-0.14 である。より好ましくは、a=0.23、b
=1.4 、c=-0.17 である。This time t k (sec) is 0.03 when the edge preheating, the edge heating, and the solid phase pressure welding are performed in the atmosphere.
It is preferable to set it to sec or more. On the other hand, if the edge preheating, edge heating, solid phase pressure is carried out in a low oxygen concentration atmosphere (in a sealed atmosphere) than atmospheric, t k is preferably the time that satisfies the following equation (1) . t k ≧ a · exp {−b · [O 2 ] c } (1) where, O 2 : oxygen concentration in the atmosphere (vol%), a,
b, c: constants, a = 0.079, b = 1.5 for low carbon steel
, C = −0.14. More preferably, a = 0.23, b
= 1.4 and c = -0.17.
【0026】この時間tk は、エッジ予熱時のオープン
管両エッジ部の加熱温度及びキュリー点以上の加熱幅、
さらにはエッジ加熱時の両エッジ部端面の加熱温度を制
御し、固相圧接時の両エッジ部端面から管中央部へ向か
っての管円周方向温度分布を調整することにより、固相
圧接後のシームの冷却速度を調整し、制御する。固相圧
接により形成された圧接シーム部では、スクイズロール
の圧接接合部外面への当接の有無、エッジ部の到達温度
あるいはスクイズロールによる管円周方向絞りの程度に
より図4(a) 、(b)に示すようにシーム部の管内外
または管内に管体肉厚の5%以上の増肉を生じることが
ある。このような場合には、圧接以降の適当な場所で、
増肉したシーム部近傍を圧延により減肉するのが好まし
い。増肉したシーム部近傍の圧延は、例えば、図5
(a) に示す圧接シーム部圧延ロール10により管内外
から圧延する。圧接シーム部圧延ロール10は、外面圧
延用ロール10a、内面圧延用ロール10bからなり、
10bは圧接シーム部圧延用ロール支持棒10cにより
支持されている。[0026] The time t k is an open pipe both edges of the heating temperature and the Curie point or more heating width during edge preheating,
In addition, by controlling the heating temperature of the end faces of both edges during edge heating and adjusting the temperature distribution in the pipe circumferential direction from the end faces of both edges to the center of the pipe during solid phase pressure welding, Adjust and control the seam cooling rate. 4 (a) and 4 (b), depending on whether or not the squeeze roll is in contact with the outer surface of the press-bonded portion, the temperature reached at the edge portion, or the degree of reduction in the pipe circumferential direction by the squeeze roll. As shown in b), the thickness of the pipe may be increased by 5% or more inside or outside the pipe or inside the pipe at the seam portion. In such a case, at an appropriate place after the welding,
It is preferable to reduce the thickness in the vicinity of the increased seam portion by rolling. Rolling in the vicinity of the increased seam portion is performed, for example, as shown in FIG.
Rolling is performed from inside and outside of a pipe by a press-seam rolling roll 10 shown in FIG. The pressure-welded seam portion rolling roll 10 includes an outer rolling roll 10a and an inner rolling roll 10b,
Reference numeral 10b is supported by a roll support rod 10c for rolling the press-seam portion.
【0027】また、前記圧接方法のうち、圧接接合部管
内外面にロール等を当接させる方法を採用することによ
って、材料を上下方向に拘束し、圧接による増肉を5%
未満に抑え、圧接以降の圧延を不要とすることも可能で
ある。例えば、図5(b)に示すスクイズロール6と圧
接シーム部内面拘束用ロール11aにより管内外から材
料を拘束し、圧接による増肉を抑制する。圧接シーム部
内面拘束用ロール11aは圧接シーム部内面拘束用ロー
ル支持棒11bにより支持されている。Further, by adopting a method in which a roll or the like is brought into contact with the inner and outer surfaces of the press-joined portion of the tube, the material is constrained in the vertical direction, and the increase in wall thickness by press-contact is 5%.
It is also possible to suppress the rolling after the pressure welding. For example, the squeeze roll 6 and the roll 11a for restraining the inner surface of the press contact seam shown in FIG. The roll 11a for restricting the inner surface of the press contact seam is supported by a roll support rod 11b for restricting the inner surface of the press contact seam.
【0028】固相圧接により形成された圧接シーム部で
は、帯鋼のエッジだれの程度、帯鋼のエッジ精整の精
度、圧接の方法あるいは圧接による増肉の度合いによ
り、圧接部の圧延の有無にかかわらず、図6に示すよう
に外面にウェルドラインと呼ばれる深さ0.2mm 程度の微
小な凹形状部分を生じることがあり、外観、シーム品質
に悪影響を及ぼす。このような場合には、圧接以降の適
当な場所でウェルドラインを除去して外面を平滑化する
のが好ましい。ウェルドラインの除去は、切削、研磨等
の加工を実施することにより行う。また、ウェルドライ
ンの除去は、圧接増肉部の圧延を行う場合には、圧延の
前後どちらで実施してもよい。In the welded seam formed by the solid-phase welding, the presence or absence of rolling of the welded portion depends on the degree of edge droop of the steel strip, the precision of the edge refining of the steel strip, the method of pressure welding, or the degree of wall thickening by pressure welding. Irrespective of this, as shown in FIG. 6, a minute concave portion having a depth of about 0.2 mm called a weld line may be formed on the outer surface, which adversely affects the appearance and seam quality. In such a case, it is preferable to remove the weld line at an appropriate place after the welding to smooth the outer surface. The removal of the weld line is performed by performing processing such as cutting and polishing. Further, the removal of the weld line may be performed before or after the rolling in the case of rolling the press-welded thickened portion.
【0029】以上述べたように、本発明によれば、オー
プン管の両エッジ部を固相圧接可能温度域に安定的に保
持でき、その後スクイズロールにより固相圧接して優れ
たシーム品質および表面肌を有する鋼管を高い生産性で
製造できる。As described above, according to the present invention, both edges of the open pipe can be stably held in the temperature range where solid-state pressure welding is possible, and then the solid-state pressure welding is performed by the squeeze roll to obtain excellent seam quality and surface quality. A steel pipe having skin can be manufactured with high productivity.
【0030】[0030]
【実施例】図1に示す本発明の実施に好適な設備列を用
いた。板厚 3.5mmの帯鋼1を成形ロール群3により連続
的に成形しオープン管7とし、さらにオープン管7を誘
導コイルを有する管体予熱装置13により 400〜650 ℃の
温度に予熱した。なお、一部の鋼管は、帯鋼1を予熱炉
2で 150〜350 ℃の温度で連続的に予熱したのち、成形
ロール群3により連続的に成形しオープン管7とし、さ
らにオープン管7を誘導コイルを有する管体予熱装置13
により 400〜650 ℃の温度に予熱した。ついで、オープ
ン管両エッジ部に表1に示す条件でエッジ予熱用誘導加
熱コイル4によりエッジ予熱を、さらにエッジ加熱用誘
導加熱コイル5によりエッジ加熱を施し、圧接シーム部
に当接する位置に設置したスクイズロール6で固相圧接
して、管寸法:60.5mmφ×3.5 mmt、規格:STKM11A の
鋼管8とした。製造された鋼管8のシーム品質、表面肌
を調査し、その結果を表1に併記する。シーム品質の評
価は、鋼管の偏平高さ比(h/D、h:偏平高さmm、
D:鋼管の外径mm)で行った。また、鋼管の表面肌の評
価は、表面粗さRmax(μm )で行った。なお、一部の
鋼管については、エッジ予熱、エッジ加熱および固相圧
接をシールド雰囲気中で行った。DESCRIPTION OF THE PREFERRED EMBODIMENTS An equipment row suitable for carrying out the present invention shown in FIG. 1 was used. The steel strip 1 having a thickness of 3.5 mm was continuously formed by the forming roll group 3 to form an open pipe 7, and the open pipe 7 was preheated to a temperature of 400 to 650 ° C. by a pipe preheating device 13 having an induction coil. Some steel pipes are continuously preheated at a temperature of 150 to 350 ° C. in a preheating furnace 2 at a temperature of 150 to 350 ° C., and then continuously formed by a forming roll group 3 to form an open pipe 7. Tube preheating device 13 with induction coil
To a temperature of 400-650 ° C. Then, both sides of the open pipe were subjected to edge preheating by the edge preheating induction heating coil 4 under the conditions shown in Table 1 and further to edge heating by the edge heating induction heating coil 5, and were installed at positions where they came into contact with the pressure welding seam. A solid pipe was welded with a squeeze roll 6 to obtain a steel pipe 8 having a pipe size of 60.5 mmφ × 3.5 mmt and a standard of STKM11A. The seam quality and surface skin of the manufactured steel pipe 8 were investigated, and the results are shown in Table 1. The seam quality was evaluated based on the flat height ratio (h / D, h: flat height mm,
D: Outer diameter of steel pipe mm). The evaluation of the surface skin of the steel pipe was performed based on the surface roughness Rmax (μm). For some steel pipes, edge preheating, edge heating, and solid-state pressure welding were performed in a shield atmosphere.
【0031】[0031]
【表1】 [Table 1]
【0032】また、帯鋼を1300℃に加熱したのち、鍛接
により60.5mmφの鍛接管とし、従来例(No.13 )とし
た。この鍛接管について、実施例と同様に鋼管の偏平高
さ比、表面粗さRmaxを測定し、表1に併記した。試験N
o.1〜No.4、No.8、No.10 、No.11 、No.14 〜No.16 の
本発明例では、偏平高さ比 0.3以下、表面粗さRmax 10
μm 以下であり、従来例の試験No.13 の鍛接管では、偏
平高さ比0.56、表面粗さRmax 37.5 μm であるのに対し
向上している。本発明の範囲を外れると、試験No.5、N
o.6、No.9のように、偏平高さ比が大きくなり、また、
試験No.12 のように、表面粗さRmaxが大きくなる。さら
に、試験No.7のように、エッジ部端面が溶融すると余盛
が形成され、ビード切削する必要が生じるため、造管速
度が100m/minに低下する。After the strip was heated to 1300 ° C., a forged pipe of 60.5 mmφ was formed by forging to obtain a conventional example (No. 13). With respect to this forged pipe, the flat height ratio and the surface roughness Rmax of the steel pipe were measured in the same manner as in the example, and are also shown in Table 1. Test N
o.1 to No.4, No.8, No.10, No.11, No.14 to No.16, the flat height ratio is 0.3 or less, and the surface roughness Rmax 10
μm or less, and in the conventional welded pipe of test No. 13, the flatness height ratio is 0.56 and the surface roughness Rmax is 37.5 μm, which is improved. When out of the scope of the present invention, test No. 5, N
o.6, No.9, the flat height ratio increases,
As in Test No. 12, the surface roughness Rmax increases. Further, as shown in Test No. 7, when the end face of the edge portion is melted, a margin is formed and it is necessary to perform bead cutting, so that the pipe forming speed is reduced to 100 m / min.
【0033】また、試験No.8は、エッジ部を1300℃を超
える温度に予熱したが、シーム品質及び表面肌は優れ、
造管速度の低下もなかった。また、本発明例の生産性
は、30ton/hrと高く、ビード切削する従来の電縫管の生
産性が15ton/hrであるのに対し、生産性が著しく向上し
ている。本発明例の試験No.1、No.3、No.14 では、圧接
シーム部の管内面に0.5 〜1.5mm の増肉がみられたが、
圧接シーム部近傍を管内外から圧延ロールで圧延し、0.
2mm 以内に減肉し、鋼管寸法の規格範囲内となった。In Test No. 8, the edge portion was preheated to a temperature exceeding 1300 ° C., but the seam quality and surface skin were excellent.
There was no decrease in the tube forming speed. The productivity of the example of the present invention is as high as 30 ton / hr, and the productivity of the conventional ERW pipe for bead cutting is 15 ton / hr, but the productivity is remarkably improved. In Tests No. 1, No. 3 and No. 14 of the present invention example, a wall thickness of 0.5 to 1.5 mm was found on the inner surface of the pipe of the press-seam seam.
The area near the welded seam is rolled from inside and outside of the pipe with rolling rolls,
The thickness was reduced to within 2mm, and the steel pipe dimensions were within the specified range.
【0034】また、試験No.2、No.4、No.15 は、圧接位
置において管外面にスクイズロールを、管内面に圧延ロ
ールをそれぞれ当接させ、材料を上下方向に拘束するこ
とによって、圧接シーム部の増肉が0.1mm 以下で鋼管寸
法の規格範囲内となり、圧接以降の圧延が不要であっ
た。本発明例の試験No.14 、No.15 では、帯鋼のエッジ
処理(具体的にはミーリングによる切削加工)を実施
し、エッジ部角を直角とした。エッジ処理を行った試験
No.14 、No.15 では、エッジ処理を行わなかった他の試
験No.1、No.2に比べ偏平高さ比が小さくなっている。In Tests No. 2, No. 4, and No. 15, the squeeze roll was brought into contact with the outer surface of the tube and the rolling roll was brought into contact with the inner surface of the tube at the pressed position to restrain the material in the vertical direction. When the thickness of the welded seam was 0.1 mm or less, it was within the standard range of steel pipe dimensions, and rolling after the welding was unnecessary. In Test Nos. 14 and 15 of the present invention, edge treatment of the steel strip (specifically, cutting by milling) was performed, and the edge portion angle was made a right angle. Test with edge treatment
No. 14 and No. 15 have smaller flat height ratios than other tests No. 1 and No. 2 in which no edge treatment was performed.
【0035】本発明例の試験No.16 では、エッジ加熱お
よび固相圧接時の雰囲気中の露点を−20℃に制御した。
これにより、雰囲気中の露点制御を行わなかった試験N
o.11に比べ偏平高さ比が小さくなっている。In Test No. 16 of the present invention, the dew point in the atmosphere during edge heating and solid-phase pressure welding was controlled to -20.degree.
As a result, the test N in which the dew point control in the atmosphere was not performed
The flat height ratio is smaller than o.11.
【0036】[0036]
【発明の効果】本発明によれば、オープン管の両エッジ
部を固相圧接可能温度域に安定的に保持でき、優れたシ
ーム品質および表面肌を有する鋼管を高い生産性で製造
できるという格段の効果を奏する。According to the present invention, both edges of an open pipe can be stably held in a temperature range in which solid pressure welding can be performed, and a steel pipe having excellent seam quality and surface skin can be manufactured with high productivity. Has the effect of
【図1】本発明の実施に好適な鋼管製造設備列の1例を
示す説明図である。FIG. 1 is an explanatory diagram showing one example of a steel pipe manufacturing facility line suitable for carrying out the present invention.
【図2】固相圧接接合部のシーム品質に及ぼす圧接後13
00℃以上に保持される時間tkと雰囲気中の酸素濃度と
の関係を示すグラフである。Fig. 2 Effect of post-welding on seam quality of solid-state welded joints
00 is a graph showing the relationship between the oxygen concentration in the time t k and the atmosphere is maintained above ° C..
【図3】固相圧接時のスクイズロール、圧接シーム部内
面拘束用ロールと圧接接合部との位置関係を示す断面図
である。FIG. 3 is a cross-sectional view showing a positional relationship between a squeeze roll, a roll for restraining the inner surface of a press-seam portion, and a press-joint portion during solid-phase press welding.
【図4】固相圧接後の鋼管断面形状の例を示す断面図で
ある。FIG. 4 is a cross-sectional view illustrating an example of a cross-sectional shape of a steel pipe after solid-phase pressure welding.
【図5】本発明の実施に好適な設備列の模式的部分断面
側面図である。FIG. 5 is a schematic partial sectional side view of an equipment row suitable for carrying out the present invention.
【図6】固相圧接後の圧接シーム部外面形状の1例を示
す断面図である。FIG. 6 is a cross-sectional view showing an example of the outer shape of a press-seam portion after solid-phase press-bonding.
【図7】鋼の比透磁率の温度依存性を示す特性図であ
る。FIG. 7 is a characteristic diagram showing temperature dependence of relative magnetic permeability of steel.
1 帯鋼 2 予熱炉 3 成形ロール群 4 エッジ予熱用誘導加熱コイル 5 エッジ加熱用誘導加熱コイル 6 スクイズロール 7 オープン管 8 鋼管 9 圧接シーム部 10 圧接シーム部圧延用ロール 10a 圧接シーム部外面圧延用ロール 10b 圧接シーム部内面圧延用ロール 10c 圧接シーム部圧延用ロール支持棒 11a 圧接シーム部内面拘束用ロール 11b 圧接シーム部内面拘束用ロール支持棒 12 圧接シーム部外面ウェルドライン 13 管体予熱装置 DESCRIPTION OF SYMBOLS 1 Strip steel 2 Preheating furnace 3 Forming roll group 4 Induction heating coil for edge preheating 5 Induction heating coil for edge heating 6 Squeeze roll 7 Open pipe 8 Steel pipe 9 Pressure welding seam part 10 Rolling pressure welding seam part rolling roll 10a Pressure welding seam part outer surface rolling Roll 10b Roll for inner surface rolling of press-welded seam part 10c Roll support rod for rolling of press-welded seam part 11a Roll for restraining inner surface of press-welded seam part 11b Roll support rod for restraining inner surface of press-welded seam part 12 Weld line for outer surface of press-welded seam part 13 Tube preheating device
───────────────────────────────────────────────────── フロントページの続き (72)発明者 依藤 章 愛知県半田市川崎町1丁目1番地 川崎製 鉄株式会社知多製造所内 (72)発明者 大西 寿雄 愛知県半田市川崎町1丁目1番地 川崎製 鉄株式会社知多製造所内 (72)発明者 橋本 裕二 愛知県半田市川崎町1丁目1番地 川崎製 鉄株式会社知多製造所内 (72)発明者 田中 伸樹 愛知県半田市川崎町1丁目1番地 川崎製 鉄株式会社知多製造所内 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Ito 1-1-1, Kawasaki-cho, Handa-shi, Aichi Prefecture Inside the Chita Works of Kawasaki Steel Corporation (72) Inventor Toshio Onishi 1-1-1, Kawasaki-cho, Handa-shi, Aichi Prefecture Kawasaki (72) Inventor Yuji Hashimoto 1-1-1, Kawasakicho, Handa-shi, Aichi Prefecture Kawasaki Steel Corporation Chita Works (72) Inventor, Nobuki Tanaka 1-1-1, Kawasakicho, Handa-shi, Aichi Prefecture Kawasaki Inside the Chita Works of Iron and Steel Corporation
Claims (13)
てオープン管とし、該オープン管の両エッジ部を加熱
し、スクイズロールで衝合接合する鋼管の製造方法にお
いて、両エッジ部の加熱に先立って、前記オープン管を
予熱し、これに続き前記オープン管の両エッジ部に、誘
導加熱によりキュリー点以上の温度に加熱するエッジ予
熱を施したのち、誘導加熱により1300℃以上、融点未満
の温度域に加熱するエッジ加熱を施し、該スクイズロー
ルで圧接することを特徴とするシーム品質および表面肌
の優れた鋼管の製造方法。1. A method for producing a steel pipe in which a steel strip is continuously formed by a forming roll to form an open pipe, and both edges of the open pipe are heated and abutted and joined by a squeeze roll. Prior to the heating, the open pipe is preheated, and subsequently, both edges of the open pipe are subjected to an edge preheating of heating to a temperature equal to or higher than the Curie point by induction heating. A method for producing a steel pipe having excellent seam quality and surface skin, characterized in that edge heating for heating to a temperature range of 1 to 3 mm is performed and pressure welding is performed with the squeeze roll.
てオープン管とし、該オープン管の両エッジ部を加熱
し、スクイズロールで衝合接合する鋼管の製造方法にお
いて、両エッジ部の加熱に先立って、前記帯鋼および前
記オープン管を予熱し、これに続き前記オープン管の両
エッジ部に、誘導加熱によりキュリー点以上の温度に加
熱するエッジ予熱を施したのち、誘導加熱により1300℃
以上、融点未満の温度域に加熱するエッジ加熱を施し、
該スクイズロールで圧接することを特徴とするシーム品
質および表面肌の優れた鋼管の製造方法。2. A method for manufacturing a steel pipe in which a steel strip is continuously formed by a forming roll into an open pipe, and both edges of the open pipe are heated and abutted and joined by a squeeze roll. Prior to this, the steel strip and the open pipe are preheated, and subsequently, both edges of the open pipe are subjected to an edge preheating of heating to a temperature equal to or higher than the Curie point by induction heating, and then 1300 ° C. by induction heating.
Above, subjected to edge heating to heat the temperature range below the melting point,
A method for producing a steel pipe having excellent seam quality and surface skin, wherein the steel pipe is pressure-welded with the squeeze roll.
℃未満の温度に加熱することを特徴とする請求項1また
は2記載の鋼管の製造方法。3. The method according to claim 1, wherein the edge preheating is performed at a temperature above the Curie point of 1300.
The method for producing a steel pipe according to claim 1, wherein the steel pipe is heated to a temperature lower than ℃.
は800 ℃以下の温度で行うことを特徴とする請求項1、
2または3記載の鋼管の製造方法。4. The preheating of the steel strip or the open pipe is performed at a temperature of 800 ° C. or less.
4. The method for producing a steel pipe according to 2 or 3.
度雰囲気中で行うことを特徴とする請求項1、2、3ま
たは4記載の鋼管の製造方法。5. The method according to claim 1, wherein the edge preheating is performed in an oxygen concentration atmosphere lower than the atmosphere.
より低い酸素濃度雰囲気中で行うことを特徴とする請求
項1、2、3、4または5記載の鋼管の製造方法。6. The method according to claim 1, wherein the edge heating and the pressure welding are performed in an oxygen concentration atmosphere lower than the atmosphere.
前記圧接は、露点が−10℃以下の雰囲気中で行うことを
特徴とする請求項1、2、3、4、5または6記載の鋼
管の製造方法。7. The steel pipe according to claim 1, wherein the edge preheating, the edge heating and the pressure welding are performed in an atmosphere having a dew point of −10 ° C. or less. Production method.
される時間tk (sec )が、0.03sec 以上または下記
(1)式を満足するtk であることを特徴とする請求項
1、2、3、4、5、6または7記載のシーム品質およ
び表面肌の優れた鋼管の製造方法。 記 tk ≧a・exp{−b・〔O2 〕c } …… (1) ここに、O2 :雰囲気中の酸素濃度(vol %)、a=0.
079 、b=1.5 、c=-0.14 。8. After the pressure, claim joint time t k which is held above 1300 ° C. (sec), which is a t k satisfying the above 0.03sec or below (1) The method for producing a steel pipe excellent in seam quality and surface skin according to 1, 2, 3, 4, 5, 6, or 7. Note that t k ≧ a · exp {−b · [O 2 ] c } (1) where, O 2 : oxygen concentration in the atmosphere (vol%), a = 0.
079, b = 1.5, c = -0.14.
材を拘束し、シーム部増肉を抑制することを特徴とする
請求項1、2、3、4、5、6、7または8記載の鋼管
の製造方法。9. The seam portion tube material is restrained from the inner and outer surfaces of the tube during the press-contact to suppress the increase in the thickness of the seam portion, and the thickness of the seam portion is suppressed. Manufacturing method of steel pipe.
ることを特徴とする請求項1、2、3、4、5、6、
7、8または9記載の鋼管の製造方法。10. The method according to claim 1, wherein, after the pressing, the vicinity of the pressing seam portion is rolled.
10. The method for producing a steel pipe according to 7, 8 or 9.
形状部分を除去して外面を平滑化することを特徴とする
請求項1、2、3、4、5、6、7、8、9または10記
載の鋼管の製造方法。11. The method according to claim 1, wherein after the pressing, a minute concave portion on the outer surface of the pressing seam portion is removed to smooth the outer surface. 11. The method for producing a steel pipe according to 9 or 10.
該エッジ部端面と該帯鋼表面のなす角度を所定の角度と
するエッジ処理を施されたものであることを特徴とする
請求項1、2、3、4、5、6、7、8、9、10または
11記載の鋼管の製造方法。12. The steel strip flattens an edge end face,
An edge treatment for making an angle between the edge portion end face and the surface of the strip steel a predetermined angle is performed. 9, 10 or
12. The method for producing a steel pipe according to 11.
による成形前または成形後行うことを特徴とする請求項
12記載の鋼管の製造方法。13. The edge treatment of the end face of the steel strip before or after forming by a forming roll.
12. The method for producing a steel pipe according to 12.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16876396A JP3684683B2 (en) | 1996-06-28 | 1996-06-28 | Steel pipe manufacturing method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16876396A JP3684683B2 (en) | 1996-06-28 | 1996-06-28 | Steel pipe manufacturing method |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH105856A true JPH105856A (en) | 1998-01-13 |
JP3684683B2 JP3684683B2 (en) | 2005-08-17 |
Family
ID=15874000
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JP16876396A Expired - Fee Related JP3684683B2 (en) | 1996-06-28 | 1996-06-28 | Steel pipe manufacturing method |
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Country | Link |
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JP (1) | JP3684683B2 (en) |
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1996
- 1996-06-28 JP JP16876396A patent/JP3684683B2/en not_active Expired - Fee Related
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JP3684683B2 (en) | 2005-08-17 |
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