JP5194728B2 - ERW pipe manufacturing method with excellent weld properties - Google Patents

ERW pipe manufacturing method with excellent weld properties Download PDF

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JP5194728B2
JP5194728B2 JP2007293854A JP2007293854A JP5194728B2 JP 5194728 B2 JP5194728 B2 JP 5194728B2 JP 2007293854 A JP2007293854 A JP 2007293854A JP 2007293854 A JP2007293854 A JP 2007293854A JP 5194728 B2 JP5194728 B2 JP 5194728B2
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JP2009119483A (en
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一仁 剣持
泰康 横山
坂田  敬
智弘 井上
邦保 大石
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Jfeスチール株式会社
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本発明は、油井のラインパイプ向けなど溶接部の靭性が要求される電縫管、あるいは、油井のケーシングパイプなどの溶接部強度が要求される電縫管の製造方法に関わる。   The present invention relates to a method for manufacturing an electric resistance welded tube such as an oil well line pipe that requires toughness of a welded portion, or an electric resistance welded tube that requires a welded portion strength such as an oil well casing pipe.
通常、管は溶接管と継目無管に大別される。溶接管は、電縫鋼管を例とするように、板をロール成形等によって丸めて端部を突き合わせて溶接して製造し、継目無管は、材料の塊を高温で穿孔しマンドレルミル等で圧延して製造する。溶接管の場合、一般に溶接部の特性は母材より劣ると言われ、管の適用に当たって、用途ごとに溶接部の靭性や強度の保証が常に議論されて問題となってきた。   Usually, pipes are roughly classified into welded pipes and seamless pipes. Welded pipes are manufactured by rolling a plate by roll forming or the like and welding by welding the end, as in the case of ERW steel pipes, and seamless pipes are made by drilling a lump of material at high temperature and using a mandrel mill, etc. Rolled and manufactured. In the case of a welded pipe, it is generally said that the properties of the welded part are inferior to that of the base metal, and in the application of the pipe, guarantees of toughness and strength of the welded part have always been discussed for each application.
例えば、原油や天然ガスなどを輸送するラインパイプでは、管を寒冷地に敷設することが多いため低温靭性が重要であり、また、原油採掘の油井では採掘管を保護するためのケーシングパイプが必要とされ、管の強度が重要視される。   For example, in line pipes that transport crude oil, natural gas, etc., low temperature toughness is important because pipes are often laid in cold regions, and casing pipes are required to protect mining pipes in oil wells for crude oil mining. The strength of the tube is regarded as important.
通常、管の母材となる熱延板(帯材、板材)は、管製造後の母材特性を考慮して成分設計や熱処理等が行われて、母材の靭性や強度等の特性が確保される。   Usually, hot-rolled sheets (band materials, plate materials) that are the base material of pipes are subjected to component design, heat treatment, etc. in consideration of the base material characteristics after pipe manufacture, and the characteristics such as toughness and strength of the base material are Secured.
しかし、溶接部の特性は、母材の成分設計や熱処理等以上に、電縫溶接方法によって大きく左右されるため、溶接技術の開発が重要であった。   However, since the characteristics of the welded part are greatly influenced by the electric resistance welding method more than the component design and heat treatment of the base metal, the development of the welding technique has been important.
電縫溶接の不良原因としては、ペネトレータと呼ばれる溶接板材の端面に生成する酸化物が、電縫溶接時に溶鋼とともに端面から排出されずに残留し、この残留したペネトレータを原因として靭性が低下し強度不足になる例が多かった。   The reason for the failure of ERW welding is that the oxide generated on the end face of the welded plate material called penetrator remains without being discharged from the end face together with the molten steel during ERW welding, and the toughness decreases due to this residual penetrator and the strength. There were many cases where there was a shortage.
そこで、従来、電縫溶接不良の主原因であるペネトレータを溶接部から除くため、溶接部の板幅端面から積極的に溶鋼を排出する技術が鋭意検討されてきた。例えば、特許文献1などに、板幅端面の形状について検討した例が記載されている。すなわち、通常、板の端面はスリットや端面研削によってほぼ矩形を呈しているが、この端面を電縫溶接前にテーパ形状に加工し、加工した端部形状によって電縫溶接時の溶鋼排出を良好にすることを特許文献1などは目的としている。   Therefore, conventionally, in order to remove the penetrator, which is the main cause of poor ERW welding, from the welded portion, a technique for actively discharging molten steel from the plate width end face of the welded portion has been intensively studied. For example, Patent Literature 1 describes an example in which the shape of the plate width end surface is examined. In other words, the end face of the plate is generally rectangular due to slits and end grinding, but this end face is processed into a tapered shape before ERW welding, and the processed end shape ensures good discharge of molten steel during ERW welding. Patent document 1 etc. aim at making it.
なお、特許文献1の概要は以下の如くである。   The outline of Patent Document 1 is as follows.
すなわち、基本的な電縫管製造ラインは図1に示すようなものであり、この電縫管製造ラインは、帯材10を、アンコイラ1から払い出し、レベラー2で平坦に矯正し、ロール成形機4で帯材10をその幅端部が上部になるように徐々に丸めていき、丸めた帯材20の左右両幅端部同士を突き合わせ、誘導加熱部5とスクイズロール(電縫溶接部)6からなる電縫溶接機で電縫溶接して管30となし、管30の溶接ビード部をビード部切削機7で切削し、切削後の管30を、サイザー8にて外径調整した後、管切断機9で所定長さに切断するという構成を有している。なお、ロール成形機4は、最後段に丸めた板端部を拘束して真円に近い形状とする所定台数のフィンパス成形スタンド群3を備えており、ここでは、第1スタンド3aと第2スタンド3bよりなっている。   That is, the basic ERW pipe production line is as shown in FIG. 1. This ERW pipe production line is a roll forming machine in which the belt material 10 is discharged from the uncoiler 1 and flattened by the leveler 2. 4, the strip 10 is gradually rounded so that the width end portion is at the top, the left and right width end portions of the round strip 20 are brought into contact with each other, and the induction heating unit 5 and the squeeze roll (electro-sealed welded portion) After the electric bead welding by the electric seam welding machine consisting of 6 and forming the pipe 30, the weld bead part of the pipe 30 is cut by the bead part cutting machine 7, and the outer diameter of the cut pipe 30 is adjusted by the sizer 8. The tube cutting machine 9 cuts it to a predetermined length. The roll forming machine 4 includes a predetermined number of fin-pass forming stand groups 3 that constrain the end of the plate rounded to the last stage to have a shape close to a perfect circle. Here, the first stand 3a and the second stand It consists of a stand 3b.
そして、特許文献1に記載の技術では、図3(a)に横断面図、図3(b)にその部分詳細図を示すように、フィンパス成形第1スタンド3aにおいて、管状に成形された帯材20の幅端部(板端部)の一部分をフィンパス孔型ロールのフィンに接触させることによって、図3(c)に示すように、管の内面側となる板端部にテーパ形状を付与するとともに、図3(d)に横断面図、図3(e)にその部分詳細図を示すように、フィンパス成形第2スタンド3bにおいて、帯材20の幅端部(板端部)の他の部分をフィンに接触させることによって、図3(f)に示すように、管の外面側となる板端部にテーパ形状を付与することで、X型開先を形成するようにしている。なお、フィンパス成形第1スタンド3a、第2スタンド3bにおけるフィンの角度は通常の1段階の角度である。
特開昭57−31485号公報
In the technique described in Patent Document 1, as shown in a cross-sectional view in FIG. 3A and a partial detailed view in FIG. 3B, a band formed into a tubular shape in the first fin-pass forming stand 3a. A part of the width end portion (plate end portion) of the material 20 is brought into contact with the fins of the fin pass hole roll to give a taper shape to the plate end portion on the inner surface side of the tube as shown in FIG. In addition, as shown in the cross-sectional view in FIG. 3D and the partial detail view in FIG. 3E, in the fin pass molding second stand 3b, in addition to the width end portion (plate end portion) of the band member 20 By bringing this part into contact with the fin, as shown in FIG. 3 (f), an X-shaped groove is formed by imparting a taper shape to the plate end portion on the outer surface side of the tube. In addition, the angle of the fin in the fin pass shaping | molding 1st stand 3a and the 2nd stand 3b is a normal 1 step | paragraph angle.
JP 57-31485 A
従来、電縫溶接部の靭性や強度を向上するため、特許文献1などのように、電縫溶接の前に帯板幅端面にテーパ形状を付与しているが、これらの方法だけでは充分な効果が得られにくい場合が多々生じていた。   Conventionally, in order to improve the toughness and strength of the electric seam welded portion, as in Patent Document 1, a taper shape is given to the band plate width end surface before the electric seam welding, but these methods are sufficient. There were many cases where it was difficult to obtain the effect.
特に、特許文献1のように、帯板の幅端面にX字開先を付与すると、スクイズロールで挟んで電縫溶接した場合、左右の帯材幅端部が上下にずれ易くて、所望の管とならず大問題であった。   In particular, as in Patent Document 1, when an X-shaped groove is applied to the width end surface of the band plate, when the electro-sewing welding is performed with the squeeze roll sandwiched, the left and right band material width end portions are easily displaced up and down, It was not a tube but a big problem.
本発明は、上記のような事情に鑑みてなされたものであり、電縫管を製造するに際して、電縫溶接前の材料(帯材)の幅端部にテーパ形状を適切に付与することによって、溶接品質を良好に保持することができる溶接部特性に優れた電縫管の製造方法を提供することを目的とするものである。   This invention is made | formed in view of the above situations, and when manufacturing an electric-welded pipe, by giving a taper shape appropriately to the width | variety edge part of the material (strip | belt material) before electric-sealing welding. It is an object of the present invention to provide a method for manufacturing an electric resistance welded tube that can maintain good welding quality and has excellent welded portion characteristics.
上記課題を解決するために、本発明は以下の特徴を有する。   In order to solve the above problems, the present invention has the following features.
[1]帯材をロール成形し左右の幅端部同士を上側で突き合わせて電縫溶接し管とする電縫管の製造方法において、ロール成形のフィンパス成形により帯材幅端部にテーパ形状を付与する際に、2段階以上の角度を有するフィンを有するフィンパス成形スタンドを用いるとともに、テーパ形状を付与するフィンパス成形スタンドのパスラインを、当該テーパ形状を付与するフィンパス成形スタンドの直前に位置するスタンドのパスライン以下とし、テーパ形状を付与しないフィンパス成形スタンドのパスラインを、当該テーパ形状を付与しないフィンパス成形スタンドの直前に位置するスタンドのパスラインと同等とすることを特徴とする溶接部特性に優れた電縫管の製造方法。 [1] In a method for manufacturing an ERW pipe which roll-forms a band material and butt-bonds the left and right width ends on the upper side to form an electric resistance welded pipe, the taper shape is formed at the width end part of the band material by roll forming fin-pass molding. When applying, a fin pass forming stand having fins having two or more angles is used, and the pass line of the fin pass forming stand that gives a tapered shape is positioned immediately before the fin pass forming stand that gives the tapered shape. The pass line of the fin pass forming stand that does not give a tapered shape is equal to the pass line of the stand that is located immediately before the fin pass forming stand that is not given the tapered shape. An excellent method for manufacturing ERW pipes.
[2]フィンパス成形で帯材の上面側幅端部または/および下面側幅端部にテーパ形状を付与することを特徴とする前記[1]に記載の溶接部特性に優れた電縫管の製造方法。   [2] The electric resistance welded tube excellent in welded portion characteristics according to [1], wherein a taper shape is imparted to the upper surface side width end portion and / or the lower surface side width end portion of the band member by fin pass molding. Production method.
[3]帯材の幅端部に付与するテーパ形状は、テーパの板厚方向に対する角度を25°〜50°とし、テーパの板厚方向の長さを板厚の20%〜45%とすることを特徴とする前記[1]または[2]に記載の溶接部特性に優れた電縫管の製造方法。   [3] The taper shape to be applied to the width end of the strip is such that the angle of the taper with respect to the plate thickness direction is 25 ° to 50 °, and the length of the taper in the plate thickness direction is 20% to 45% of the plate thickness. The method for producing an electric resistance welded tube excellent in welded portion characteristics according to the above [1] or [2].
本発明は著しく良好な靭性および溶接強度を備えた電縫管を得ることができる。   The present invention can obtain an electric resistance welded tube having remarkably good toughness and weld strength.
前述したように、従来、電縫溶接部の靭性や強度を向上するため、電縫溶接の前に帯板幅端面にテーパ形状を付与しているが、これらの方法だけでは充分な効果が得られにくい場合が多々生じており、特に、特許文献1のように、帯板の幅端面にX字開先を付与すると、スクイズロールで挟んで電縫溶接した場合、左右の帯材幅端部が上下にずれ易くて、所望の管とならず大問題であった。   As described above, conventionally, in order to improve the toughness and strength of the ERW weld, a taper shape is given to the end face of the strip width before ERW welding. However, these methods alone can provide a sufficient effect. There are many cases in which it is difficult to bend, and in particular, when an X-shaped groove is applied to the width end surface of the belt plate as in Patent Document 1, when the electro-sewing welding is performed with a squeeze roll, the left and right band material width end portions Was easily displaced up and down, and it was not a desired tube, which was a big problem.
そこで、本発明者らは、帯材幅端部の板厚中央部にほぼ垂直な面を形成させながら帯材幅端部のコーナ部にテーパ形状を付与する方法を採用した。すなわち、板厚中央部にほぼ垂直な面を形成させることによって、スクイズロールで挟んだ場合に、安定して左右の帯板幅端部を突き合わせることが可能であり、電縫溶接が安定して可能になることによる。   Therefore, the present inventors have adopted a method of imparting a taper shape to the corner portion of the strip width end portion while forming a surface substantially perpendicular to the central portion of the thickness of the strip width end portion. In other words, by forming a surface that is almost perpendicular to the center of the plate thickness, when sandwiched between squeeze rolls, it is possible to abut the left and right strip width ends stably, and stable ERW welding. Depending on what is possible.
次に、所望のテーパ形状を得るために、本発明者らはフィンパス成形を活用することを検討した。本発明者らの検討によれば、フィンパス孔型ロールに材料の円周方向全周が充満しなくとも、材料がフィンパス孔型ロールに装入される際に、材料幅端部がフィンに強圧されて、材料幅端部がフィン部に完全充満することを把握した。すなわち、材料がフィンパス孔型ロールに装入される場合、フィンに接触した材料幅端部およびそのほぼ180°反対側に位置する材料幅中央部(管の底の部分)とが梁撓みの状態となって、断面を円弧形状に曲げようとする材料の反力が大きく作用して、たとえ材料がフィンパス孔型ロールに充満しなくとも、材料幅端部には円周方向に大きな圧縮力が作用し、その結果、材料幅端部はフィンに強圧されてフィンの形状がそのまま材料幅端部に転写されることを把握した。   Next, in order to obtain a desired taper shape, the present inventors examined utilizing fin pass molding. According to the study by the present inventors, even when the entire circumferential direction of the material is not filled in the fin pass hole-type roll, when the material is charged into the fin pass hole type roll, the material width end is strongly pressed against the fin. As a result, it was grasped that the material width end part completely filled the fin part. That is, when the material is charged into the fin pass hole type roll, the material width end portion in contact with the fin and the material width center portion (the bottom portion of the tube) located on the opposite side of 180 ° are in a state of beam deflection. As a result, the reaction force of the material that attempts to bend the cross section into an arc shape is greatly affected, and even if the material does not fill the fin pass hole roll, a large compressive force is exerted on the material width end in the circumferential direction. As a result, it was grasped that the material width end portion was strongly pressed by the fin and the shape of the fin was transferred as it was to the material width end portion.
そこで、本発明者らは、上記のように、材料幅端部がフィンパス孔型ロールにおいてフィンに強圧されることに着目して、この現象を材料幅端部へのテーパ形状の付与に積極的に活用することにした。すなわち、フィンパス孔型ロールにおいて、フィンに2段階以上のテーパを付与しておけば、材料幅端部に所望とするテーパ形状を充分付与できるわけである。   Therefore, the present inventors pay attention to the fact that the material width end portion is strongly pressed by the fins in the fin pass hole type roll as described above, and this phenomenon is positively applied to the taper shape to the material width end portion. I decided to use it. That is, in the fin pass hole type roll, if a fin having two or more levels of taper is provided, a desired taper shape can be sufficiently provided to the material width end portion.
ちなみに、フィンパス成形において、管状になった帯材(管状帯材)の内面側、外面側のいずれか片側の幅端部にテーパ形状を付与する場合は、2段階の角度を有するフィン形状とすればよい。また、フィンパス成形において、管状になった帯材(管状帯材)の内面側と外面側の幅端部に同時にテーパ形状を付与する場合は、3段階の角度を有するフィン形状とすればよい。   By the way, in the fin pass molding, when a tapered shape is given to the width end of either the inner side or the outer side of the tubular strip (tubular strip), it is assumed that the fin has a two-step angle. That's fine. Further, in the fin pass molding, in the case where a tapered shape is simultaneously applied to the inner side and the outer side of the strip (tubular strip) formed into a tubular shape, the fin may have a three-stage angle.
ただし、2段階または3段階としたフィンのいずれかの角度がフィンパス孔型ロールの垂直方向より大きな角度になると、帯材幅端部がフィンにより削り取られて、「ひげ」と称する余肉材が発生することがあり、フィンパス成形時に傷を発生させるとともに、電縫溶接のスパークの原因となるので、フィンの角度は垂直方向以下にしておくとよい。   However, if the angle of either the two-stage or three-stage fin is larger than the vertical direction of the fin pass hole roll, the band width end is scraped off by the fin, and the surplus material called “beard” is This may occur, and may cause scratches when forming the fin path, and may cause sparks in ERW welding.
また、2スタンド以上でのフィンパス成形が可能である場合、1つのスタンドのフィンが2段階の角度のテーパを有するようにして、帯材幅端部の一方(例えば、管状帯材の内面側)にテーパ形状を付与し、別のスタンドのフィンが前記と異なる角度の2段階のテーパを有するようにして、帯材幅端部の他方(例えば、管状帯材の外面側)にテーパ形状を付与するとよい。なお、フィンパス成形で帯材幅端部の一方にテーパ形状を付与した場合、その部分は強圧によって著しく加工硬化するため、さらに別のスタンドで帯材幅端部の他方にテーパ形状を付与しても、前段スタンドで付与したテーパ形状は比較的潰れにくくなる。従って、フィンパス成形後の帯材幅端部には内面側、外面側とも所望のテーパ形状が付与できるわけである。   In addition, when fin path molding with two or more stands is possible, one of the end portions of the strip width (for example, the inner surface side of the tubular strip) such that the fins of one stand have a taper with two stages of angles. A taper shape is given to the other end of the strip width (for example, the outer surface side of the tubular strip) so that the fin of another stand has a two-step taper of an angle different from the above. Good. In addition, when a taper shape is given to one of the strip width ends by fin pass molding, the portion is significantly hardened by strong pressure, so a taper shape is given to the other of the strip width ends by another stand. However, the taper shape provided by the front stand is relatively difficult to be crushed. Therefore, a desired taper shape can be imparted to both the inner surface side and the outer surface side of the band material width end portion after the fin pass molding.
その上で、フィンパス成形スタンドでより一層安定して帯材幅端部にテーパ形状を付与するには、テーパ形状を付与するスタンドのパスラインを、当該スタンドの直前に位置するスタンドのパスラインと同等またはそれ以下にするとよい。   In addition, in order to give a taper shape to the band width end portion more stably in the fin pass forming stand, the pass line of the stand that gives the taper shape is the same as the pass line of the stand located immediately before the stand. Equivalent or less.
例えば、図1の電縫管製造ラインにおいて、フィンパス成形第2スタンド3bで帯材20の幅端部の内面側または/および外面側にテーパ形状を付与する場合には、その第2スタンド3bのパスラインを、直前に位置するフィンパス成形第1スタンド3aのパスラインと同等またはそれ以下にする。   For example, in the case of the ERW pipe manufacturing line in FIG. 1, when a tapered shape is given to the inner surface side and / or the outer surface side of the width end portion of the band member 20 by the fin pass molding second stand 3b, the second stand 3b The pass line is equal to or less than the pass line of the fin pass molding first stand 3a located immediately before.
また、図1の電縫管製造ラインにおいて、フィンパス成形第1スタンド3aで帯材20の幅端部の内面側または/および外面側にテーパ形状を付与する場合には、その第1スタンド3aのパスラインを、直前に位置するロール成形スタンド4sのパスラインと同等またはそれ以下にする。   Further, in the case of the ERW pipe manufacturing line of FIG. 1, in the case where a tapered shape is given to the inner surface side and / or the outer surface side of the width end portion of the band member 20 in the fin-pass molding first stand 3a, The pass line is equal to or less than the pass line of the roll forming stand 4s located immediately before.
すなわち、帯材20の幅端部の内面側、外面側(帯材10の幅端部の上面側、下面側)の一方もしくは両方にフィンパス成形でテーパ形状を付与するには、フィンパス孔型ロールへの充満度を向上する必要があるが、テーパ形状を付与する当該スタンドのパスラインが、その直前のスタンドのパスラインに比較して高い場合、帯材幅端部は当該スタンドの水平ロールでなく、フィンに先に接触しやすくなる。フィンパス孔型ロール入側においてフィンは回転によって内面側に移動しているため、帯板幅端部がフィンに接触すると、周方向にアプセット力が強く加わることも作用して、帯材幅端部が内面側に倒れ込んでフィンのテーパ部分に充満せず、帯材幅端部にテーパ形状が付与されない場合が生じた。   That is, in order to give a taper shape to one or both of the inner surface side and the outer surface side (the upper surface side and the lower surface side of the width end portion of the band material 10) of the band material 20 by fin path molding, a fin path hole roll However, when the pass line of the stand that gives the taper shape is higher than the pass line of the immediately preceding stand, the band material width end is the horizontal roll of the stand. It becomes easy to contact the fin first. Since the fin is moved to the inner surface side by rotation on the fin pass hole type roll entry side, when the strip plate width end portion comes into contact with the fin, an upset force is also applied in the circumferential direction, and the strip width end portion Collapsed to the inner surface side and did not fill the taper portion of the fin, and the taper shape was not given to the band width end.
これに対して、テーパ形状を付与する当該スタンドのパスラインが、その直前のスタンドのパスラインに比較して同等またはそれ以下の場合は、帯材幅端部は当該スタンドの水平ロールに先に接触しやすくなり、周方向にアプセット力が強く作用して、帯材幅端部は水平ロール面を円周方向に容易に移動して、フィン部に充満しやすくなるわけである。   On the other hand, if the pass line of the stand to which the taper shape is given is equal to or less than the pass line of the immediately preceding stand, the band material width end is first before the horizontal roll of the stand. It becomes easy to contact, and the upset force acts strongly in the circumferential direction, and the band width end portion easily moves in the circumferential direction on the horizontal roll surface and easily fills the fin portion.
そして、フィンパス成形後の電縫溶接直前のテーパ形状について最適化を図った結果、垂線からの角度(テーパの板厚方向に対する角度)を25°〜50°とし、テーパ開始位置から終了位置までの垂線の長さ(テーパの板厚方向の長さ)を板厚の20%〜45%とすると良いことを把握した。   Then, as a result of optimization of the taper shape immediately before the ERW welding after the fin pass molding, the angle from the perpendicular (angle with respect to the thickness direction of the taper) is set to 25 ° to 50 °, and the taper start position to the end position is set. It was understood that the length of the perpendicular (the length of the taper in the thickness direction) should be 20% to 45% of the thickness.
すなわち、垂線からの角度(テーパ角度)を25°未満とすると、板厚中央部からの溶鋼排出が不十分となってペネトレータが残留して不良となり、電縫溶接後の靭性や強度が低下し、垂線からの角度(テーパ角度)を50°超えとすると、電縫溶接後にもそのテーパ形状が製品の管の疵として残留し問題である。さらに、テーパ開始位置から終了位置までの垂線の長さ(テーパ高さ)について、板厚の20%未満であると、板厚中央部の溶鋼排出が不十分となってペネトレータが残留しやすくなり、板厚の45%を超えると、スクイズロールで挟んで電縫溶接した場合、左右の帯材幅端部が上下にずれ易くて電縫溶接が正常にできず、製品としての管にすることできない場合が多々生じて問題であり、電縫溶接ができた場合でも、その後にテーパ形状が製品の管の疵として残留し問題である。   That is, if the angle from the perpendicular (taper angle) is less than 25 °, the molten steel discharge from the central portion of the plate thickness becomes insufficient, the penetrator remains and becomes defective, and the toughness and strength after ERW welding decrease. If the angle from the perpendicular (taper angle) exceeds 50 °, the taper shape remains as a flaw in the tube of the product even after the electric resistance welding. Furthermore, if the length of the perpendicular line from the taper start position to the end position (taper height) is less than 20% of the plate thickness, the molten steel discharge at the center of the plate thickness becomes insufficient and the penetrator tends to remain. If it exceeds 45% of the plate thickness, when the ERW welding is sandwiched between squeeze rolls, the width ends of the left and right strips are easily displaced up and down, and the ERW welding cannot be performed normally. There are many cases where this is not possible, and even when electro-welding is possible, the taper shape remains as a flaw in the tube of the product after that.
上記のような本発明の一実施形態を図面に基づいて以下に述べる。   One embodiment of the present invention as described above will be described below with reference to the drawings.
本発明の一実施形態において用いる電縫管製造ラインは、前述の図1に示したものと同様である。すなわち、この電縫管製造ラインは、帯材10を、アンコイラ1から払い出し、レベラー2で平坦に矯正し、ロール成形機4で帯材10をその幅端部が上部になるように徐々に丸めていき、丸めて管状になった帯材20の左右両幅端部同士を突き合わせ、誘導加熱部5とスクイズロール(電縫溶接部)6からなる電縫溶接機で電縫溶接して管30となし、管30の溶接ビード部をビード部切削機7で切削し、切削後の管30をサイザー8にて外径調整した後、管切断機9で所定長さに切断するという基本構成を有している。   The electric sewing tube manufacturing line used in one embodiment of the present invention is the same as that shown in FIG. That is, in this electric sewing tube manufacturing line, the strip material 10 is discharged from the uncoiler 1 and straightened by the leveler 2, and the strip material 10 is gradually rounded by the roll forming machine 4 so that the width end portion is at the top. Then, the left and right width end portions of the strip 20 which has been rounded into a tubular shape are brought into contact with each other, and subjected to electric resistance welding with an electric resistance welding machine including an induction heating portion 5 and a squeeze roll (electricity welding portion) 6. The basic configuration is such that the weld bead part of the pipe 30 is cut by the bead part cutting machine 7, the outer diameter of the cut pipe 30 is adjusted by the sizer 8, and then cut to a predetermined length by the pipe cutting machine 9. Have.
そして、この実施形態においては、ロール成形機4は最後段に複数スタンド(ここでは、第1スタンド3aと第2スタンド3b)からなるフィンパス成形スタンド群3を備えており、その第2スタンド3bが、図2(a)に断面図を示し、図2(b)にその部分詳細図を示すように、3段階のテーパ(1段目の傾斜部垂直長さδ、2段目のテーパ傾斜角度γ、3段目のテーパ傾斜角度α、3段目の傾斜部垂直長さβ)となったフィン形状を備えており、そのフィン形状を帯材20の幅端部に転写することによって、図2(c)に示すように、帯材20の外面側の左右両幅端部に、テーパ角度がαでテーパ高さがβのテーパ形状を付与し、帯材20の内面側の左右両幅端部に、テーパ角度がγでテーパ高さがψのテーパ形状を付与するようになっている。   In this embodiment, the roll forming machine 4 includes a fin-pass forming stand group 3 including a plurality of stands (here, the first stand 3a and the second stand 3b) at the last stage, and the second stand 3b FIG. 2 (a) shows a cross-sectional view, and FIG. 2 (b) shows a partial detailed view thereof. As shown in FIG. γ, a third-stage taper inclination angle α, and a third-stage inclined portion vertical length β) are provided, and the fin shape is transferred to the width end portion of the band member 20 to obtain a figure. 2 (c), the left and right width ends on the outer surface side of the band member 20 are provided with a tapered shape having a taper angle of α and a taper height of β, and both left and right widths on the inner surface side of the band member 20. A tapered shape with a taper angle of γ and a taper height of ψ is added to the end. The
その上で、この実施形態においては、帯材20の幅端部にテーパ形状を付与する第2スタンド3bのパスラインが、直前に位置する第1スタンド3aのパスラインと同等またはそれ以下になっている。   In addition, in this embodiment, the pass line of the second stand 3b that gives the taper shape to the width end portion of the band member 20 is equal to or less than the pass line of the first stand 3a located immediately before. ing.
なお、上記において、第1スタンド3aにおいて帯材幅端部の一方(例えば、管状帯材の内面側)にテーパ形状を付与し、第2スタンド3bにおいて帯材幅端部の他方(例えば、管状帯材の外面側)にテーパ形状を付与する場合には、帯材20の幅端部の一方にテーパ形状を付与する第1スタンド3aのパスラインを、直前に位置するロール成形スタンド4sのパスラインと同等またはそれ以下にするとともに、帯材20の幅端部の他方にテーパ形状を付与する第2スタンド3bのパスラインを、直前に位置する第1スタンドのパスラインと同等またはそれ以下にする。   In the above, one of the band material width end portions (for example, the inner surface side of the tubular band material) is given a taper shape in the first stand 3a, and the other one of the band material width end portions (for example, tubular) in the second stand 3b. When a taper shape is given to the outer surface side of the band material, a pass line of the roll forming stand 4s located immediately before the pass line of the first stand 3a that gives the taper shape to one of the width ends of the band material 20 is provided. The pass line of the second stand 3b that gives the taper shape to the other of the width end portions of the band member 20 is made equal to or less than the pass line of the first stand located immediately before. To do.
以下、実施例に基づいて説明する。   Hereinafter, a description will be given based on examples.
ここでは、板幅1920mm×19.1tmmの帯材(鋼帯)を用いて、φ600の電縫管を製造した。   Here, an electric resistance welded tube of φ600 was manufactured using a strip (steel strip) having a plate width of 1920 mm × 19.1 tmm.
そして、製造した電縫管の溶接部から試験片を切り出してシャルピー試験を行い、性能を評価した。シャルピー試験片は、管長手方向の相違する10点から1本ずつ、試験片長さ方向を管円周方向に平行にし、ノッチ長さ中心を溶接部肉厚中心位置として採取し、JIS5号の2mmVノッチ衝撃試験片として、−46℃での衝撃試験を行い、吸収エネルギー、脆性破面率を測定した。なお、吸収エネルギーは125J以上、脆性破面率が35%以下を性能許容範囲とした。   And the test piece was cut out from the weld part of the manufactured ERW pipe, the Charpy test was done, and the performance was evaluated. Each Charpy test piece is taken from 10 points with different pipe longitudinal directions, the specimen length direction is parallel to the pipe circumferential direction, the notch length center is taken as the weld thickness center position, and 2 mmV of JIS5 An impact test at −46 ° C. was performed as a notch impact test piece, and the absorbed energy and the brittle fracture surface ratio were measured. In addition, the absorbed energy was 125 J or more and the brittle fracture surface ratio was 35% or less as the allowable performance range.
参考例1)参考例1として、前述の実施形態に基づいて上記の電縫管を製造した。その際、3スタンドからなるフィンパス成形スタンド群の第1スタンドから第3スタンドのパスラインを同一にして、その第2スタンドにおいて、帯材の内面側の左右幅端部にテーパ形状を付与し、その第3スタンドにおいて、帯材の外面側の左右幅端部にテーパ形状を付与した。目標としたフィンパス成形後のテーパ形状(電縫溶接直前のテーパ形状)
は、帯材の内面側および外面側ともに、テーパ角度が30°でテーパ高さが5mm(板厚の26%)のほぼ直線上のテーパ形状である。
Reference Example 1 As Reference Example 1, the above-described electric resistance welded tube was manufactured based on the above-described embodiment. At that time, the pass lines from the first stand to the third stand of the fin pass molding stand group consisting of three stands are made the same, and in the second stand, a taper shape is given to the left and right width end portions on the inner surface side of the band material, In the third stand, a taper shape was given to the left and right width end portions on the outer surface side of the strip. Target taper shape after fin pass molding (taper shape just before ERW welding)
Is a substantially linear taper shape with a taper angle of 30 ° and a taper height of 5 mm (26% of the plate thickness) on both the inner surface side and the outer surface side of the strip.
(本発明例2)本発明例2として、前述の実施形態に基づいて上記の電縫管を製造した。その際、2スタンドからなるフィンパス成形スタンド群の第1スタンドのパスラインを、その直前に位置するロール成形スタンドのパスラインに比較して20mm低くし、その第1スタンドにおいて、帯材の内面側と外面側の左右幅端部にテーパ形状を付与した。第2スタンドにおいて、前記のテーパ形状に多少の潰れも発生したが、目標としたフィンパス成形後のテーパ形状(電縫溶接直前のテーパ形状)は、帯材の内面側および外面側ともに、テーパ角度が40°でテーパ高さが7.2mm(板厚の38%)のほぼ直線上のテーパ形状である。   (Invention Example 2) As Invention Example 2, the above-described electric resistance welded tube was manufactured based on the above-described embodiment. At that time, the pass line of the first stand of the fin pass forming stand group consisting of two stands is lowered by 20 mm as compared with the pass line of the roll forming stand located immediately before, and the inner side of the band material in the first stand. And the taper shape was given to the right-and-left width end part on the outer surface side. In the second stand, the taper shape was somewhat crushed, but the target taper shape after the fin pass molding (taper shape just before ERW welding) is the taper angle on both the inner surface side and the outer surface side of the band material. Is a substantially linear taper shape with a taper height of 7.2 mm (38% of the plate thickness).
(比較例1)比較例1として、3スタンドからなるフィンパス成形スタンド群の第2スタンドのパスラインを第1スタンドのパスラインに比較して5mm高くし、第3スタンドのパスラインを第2スタンドのパスラインに比較して10mm高くするとともに、その第2スタンドにおいて、帯材の内面側幅端部を板厚方向のほぼ1/2までフィンに接触させて、テーパ角度を20°としたほぼ直線上のテーパ形状の付与を狙い、その第3スタンドにおいて、帯材の外面側幅端部に板厚方向のほぼ1/2までのテーパ形状を付与することを狙ってフィンパス成形を行った。   (Comparative Example 1) As Comparative Example 1, the pass line of the second stand of the fin-pass molding stand group consisting of 3 stands is made 5 mm higher than the pass line of the first stand, and the pass line of the third stand is set to the second stand. 10 mm higher than the pass line, and in the second stand, the inner side width end of the strip is brought into contact with the fin to almost half of the plate thickness direction so that the taper angle is about 20 °. With the aim of providing a linear taper shape, fin pass molding was performed in the third stand with the aim of providing a taper shape up to approximately ½ in the plate thickness direction at the outer surface side width end of the strip.
(比較例2)比較例2として、2スタンドからなるフィンパス成形スタンド群において、第1スタンドのパスラインを直前のスタンド(ケージロール成形機の最終スタンド)に比較して5mm高くし、第2スタンドのパスラインを第1スタンドのパスラインに比較して10mm高くしてフィンパス成形を行った。なお、帯材の幅端面にはテーパ形状は付与せず、ほぼ矩形になるようにした。   (Comparative Example 2) As a comparative example 2, in a fin-pass molding stand group consisting of two stands, the pass line of the first stand is made 5 mm higher than the immediately preceding stand (final stand of the cage roll molding machine), and the second stand The pass line was made 10 mm higher than the pass line of the first stand to perform fin pass molding. In addition, the taper shape was not provided to the width | variety end surface of the strip | belt material, but it was made to become a substantially rectangular shape.
これらの参考例1、本発明例2と比較例1、2について、電縫溶接直前の帯材幅端部の形状を実測した結果と、製造後の電縫管の溶接部におけるシャルピー衝撃値と脆性破面率を測定した結果を表1に示す。 About these reference examples 1, this invention example 2, and comparative examples 1 and 2, as a result of actually measuring the shape of the band width end immediately before the electric resistance welding, the Charpy impact value at the welded portion of the electric resistance welding pipe The results of measuring the brittle fracture surface ratio are shown in Table 1.
表1より、参考例1、本発明例2による電縫管は、溶接部の衝撃強度が高く脆性破面率が小さくて、靭性が良好であって、製品の信頼性が高い。これに対して、比較例1、2で製造した電縫管は、溶接部の衝撃強度が低く脆性破面率が大きくて、靭性が低下しており、製品の信頼性に乏しかった。フィンパス成形後の電縫溶接直前における帯材幅端部形状を比較すると、本発明例1、2の場合、帯材の内面側、外面側に所望するテーパ形状が付与されていたのに対して、比較例1、2では、いずれもテーパ形状が不足しており、フィンパス成形で板厚方向に平滑化されてしまったことが分かる。 From Table 1, the ERW pipe according to Reference Example 1 and Invention Example 2 has high impact strength at the welded portion, low brittle fracture surface ratio, good toughness, and high product reliability. On the other hand, the electric resistance welded pipes manufactured in Comparative Examples 1 and 2 had low impact strength at the welded portion, high brittle fracture surface ratio, reduced toughness, and poor product reliability. When comparing the band width end shape immediately before ERW welding after the fin pass molding, in the case of the present invention examples 1 and 2, the desired taper shape was given to the inner surface side and outer surface side of the band material In Comparative Examples 1 and 2, it can be seen that the taper shape is insufficient, and smoothing is performed in the plate thickness direction by fin pass molding.
これにより、本発明によって溶接部特性の良好な電縫管を製造できることが確認された。   Thereby, it was confirmed that the electric resistance welded tube with a favorable welded part characteristic can be manufactured by the present invention.
本発明の一実施形態における電縫管製造ラインを示す図。The figure which shows the ERW pipe manufacturing line in one Embodiment of this invention. 本発明の一実施形態における帯材幅端部へのテーパ形状の付与を示す図。The figure which shows provision of the taper shape to the strip | belt-material width | variety edge part in one Embodiment of this invention. 従来技術(特許文献1)を示す図。The figure which shows a prior art (patent document 1).
符号の説明Explanation of symbols
1 アンコイラ
2 レベラー
3 フィンパス成形スタンド群
3a フィンパス成形スタンドの第1スタンド
3b フィンパス成形スタンドの第2スタンド
4 ロール成形機
4s フィンパス成形スタンドの直前のロール成形スタンド
5 誘導加熱装置(コンタクトチップ)
6 スクイズロール(電縫溶接部)
7 ビード部切削機
8 サイザー
9 管切断機
10 帯材
20 管状に成形された帯材
30 管
DESCRIPTION OF SYMBOLS 1 Uncoiler 2 Leveler 3 Fin pass forming stand group 3a 1st stand of a fin pass forming stand 3b 2nd stand of a fin pass forming stand 4 Roll forming machine 4s Roll forming stand just before a fin pass forming stand 5 Induction heating apparatus (contact chip)
6 squeeze roll
7 Bead cutting machine 8 Sizer 9 Pipe cutting machine 10 Band 20 Band 30 formed into a tube

Claims (3)

  1. 帯材をロール成形し左右の幅端部同士を上側で突き合わせて電縫溶接し管とする電縫管の製造方法において、ロール成形のフィンパス成形により帯材幅端部にテーパ形状を付与する際に、2段階以上の角度を有するフィンを有するフィンパス成形スタンドを用いるとともに、テーパ形状を付与するフィンパス成形スタンドのパスラインを、当該テーパ形状を付与するフィンパス成形スタンドの直前に位置するスタンドのパスライン以下とし、テーパ形状を付与しないフィンパス成形スタンドのパスラインを、当該テーパ形状を付与しないフィンパス成形スタンドの直前に位置するスタンドのパスラインと同等とすることを特徴とする溶接部特性に優れた電縫管の製造方法。 In a method of manufacturing an ERW pipe that roll-forms a band and butt welds the left and right width ends on the upper side to form a pipe that is electro-welded, when a taper shape is applied to the band-width end by roll forming fin path molding to, with use of the fin pass forming stand having a fin with an angle of more than two stages, the pass line of the fin pass forming stand to impart a tapered shape, the stand is located immediately before the fin pass forming stand to impart the tapered passline The pass line of the fin pass forming stand not provided with the taper shape is equivalent to the pass line of the stand located immediately before the fin pass forming stand not provided with the taper shape. A method for manufacturing a sewing tube.
  2. フィンパス成形で帯材の上面側幅端部または/および下面側幅端部にテーパ形状を付与することを特徴とする請求項1に記載の溶接部特性に優れた電縫管の製造方法。   The method for producing an electric resistance welded tube excellent in welded portion characteristics according to claim 1, wherein a taper shape is imparted to the upper surface side width end portion and / or the lower surface side width end portion of the band member by fin pass molding.
  3. 帯材の幅端部に付与するテーパ形状は、テーパの板厚方向に対する角度を25°〜50°とし、テーパの板厚方向の長さを板厚の20%〜45%とすることを特徴とする請求項1または2に記載の溶接部特性に優れた電縫管の製造方法。 The taper shape to be applied to the width end of the strip is characterized in that the angle of the taper with respect to the plate thickness direction is 25 ° to 50 °, and the length of the taper in the plate thickness direction is 20% to 45% of the plate thickness. The method for producing an electric resistance welded tube excellent in welded portion characteristics according to claim 1 or 2.
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