JPS6240935A - Manufacture of thick wall electric welded tube - Google Patents

Manufacture of thick wall electric welded tube

Info

Publication number
JPS6240935A
JPS6240935A JP18254285A JP18254285A JPS6240935A JP S6240935 A JPS6240935 A JP S6240935A JP 18254285 A JP18254285 A JP 18254285A JP 18254285 A JP18254285 A JP 18254285A JP S6240935 A JPS6240935 A JP S6240935A
Authority
JP
Japan
Prior art keywords
edges
hoop
forming
welded tube
steel strip
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
JP18254285A
Other languages
Japanese (ja)
Inventor
Ichiro Kokubo
小久保 一郎
Takuo Hosoda
細田 卓夫
Hakobu Shiyukuhisa
宿久 運
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.)
Kobe Steel Ltd
Original Assignee
Kobe Steel Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kobe Steel Ltd filed Critical Kobe Steel Ltd
Priority to JP18254285A priority Critical patent/JPS6240935A/en
Publication of JPS6240935A publication Critical patent/JPS6240935A/en
Pending legal-status Critical Current

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Abstract

PURPOSE:To manufacture an electric welded tube having a high roundness by heating in advance both edges of hoop prior to forming by a roller, and executing moderately and easily the forming of an edge part. CONSTITUTION:As for hoop 2 which has been fed out of an uncoiler 1, both its edges are heated continuously by a high frequency induction heating device 11. Thereafter, said hoop passes through a forming roller group of stand groups 3, 4, etc., brought to bending little by little, and becomes a tubular pipe stock 5 of an almost tube shape in the end. Prior to this roll forming, the hoop 2 is pre-heated, and the strength is lowered to about 1/2 of the cold strength, therefore, bending of the edge part is executed easily, and roundness of the pipe stock becomes high. Subsequently, the edge of the hoop which has become the tubular pipe stock 5 is heated by a high frequency induction heating device 6, both the edges are butted and an upset is executed by a squeeze roller 7, they are joined, and an electric welded tube 8 having a high roundness is obtained.

Description

【発明の詳細な説明】 〈産業−にの利用分野〉 本発明は、厚肉電縫管の製造方法に関する。[Detailed description of the invention] <Industrial application field> The present invention relates to a method for manufacturing a thick-walled electric resistance welded tube.

〈従来の技術〉 第7図に一般的に行なわれている電縫管の製造]−程の
概略を示す。アンコイラlから送り出された帯鋼2は、
それぞれ対をなす駆動ロールからなる複数段のブレーク
ダウンスタンド3、フィンパススタンド4を冷間で通過
し、順次ロールの形状に沿って成形され、最後にほぼ管
状の管状素管5となる。次いて、エツジのつき合わせ部
を高周波誘導加熱装置6で加熱し、スクイズロール7で
加圧圧接して電縫管8が形成される。
<Prior Art> Fig. 7 shows an outline of the manufacturing process of electric resistance welded pipes which is generally carried out. The steel strip 2 sent out from the uncoiler l is
It passes cold through a plurality of stages of breakdown stands 3 and fin pass stands 4, each consisting of a pair of driving rolls, and is sequentially shaped according to the shape of the rolls, and finally becomes a substantially tubular blank tube 5. Next, the abutting portions of the edges are heated with a high-frequency induction heating device 6 and pressed together with a squeeze roll 7 to form an electric resistance welded tube 8.

〈発明が解決しようとする問題点〉 」二連のような従来のロール成形方法では、厚肉になる
ほど、帯鋼のエツジ部分の成形が難しくなって未成形部
が残るため、第8図に示すようにつき合わせ部8aが洋
梨状に突き出るルーフィング現象が生じやすくなる。こ
のため、帯鋼の厚さをt1成形後の管外径をDとして、
t/D≧0.20程度の厚内になると真円度が出に(く
なり、工業的にはL/D≦0.15が限度であった。
<Problems to be Solved by the Invention> In conventional roll forming methods such as double roll forming, the thicker the steel strip becomes, the more difficult it becomes to form the edge portions of the steel strip, leaving unformed portions. As shown, a roofing phenomenon in which the abutting portion 8a protrudes in a pear-shape is likely to occur. For this reason, the thickness of the steel strip is t1, and the outer diameter of the tube after forming is D,
When the thickness falls within the range of t/D≧0.20, roundness becomes noticeable, and L/D≦0.15 is the industrial limit.

本発明はこのような点に着目し、厚肉の場合でもつき合
わせ部の成形を容易とし、良好な真円度を有する厚肉電
縫管を得られるようにすることを課題としてなされたも
のである。
The present invention has focused on these points, and has been made with the object of making it possible to easily form the abutting portion even in the case of thick walls, and to obtain a thick-walled electric resistance welded tube with good roundness. It is.

く問題点を解決するための手段〉 1−記の課題達成のため、本発明の厚肉電縫管の製造方
法では、帯鋼をロール成形する前にその両エツジをあら
かじめ加熱するにうにし、その後連続的にロール成形し
ながらエツジのつき合わl一部を溶接している。
Means for Solving the Problems> In order to achieve the problem described in 1-, the method for manufacturing a thick-walled electric resistance welded pipe of the present invention includes preheating both edges of the steel strip before roll forming it. Then, while continuous roll forming, a part of the edge abutment is welded.

〈作用〉 本発明の方法によれば、帯鋼のエツジ部分があらかじめ
加熱されているので、厚肉の場合でもエツジ部分の成形
か無理なく容易に行なイつれ、真円度の高い電縫管が得
られる。
<Function> According to the method of the present invention, since the edge portions of the steel strip are preheated, the edge portions can be easily and easily formed even in the case of thick steel strips, resulting in highly rounded electric welding. A tube is obtained.

〈実施例〉 以下、図示の実施例について説明する。<Example> The illustrated embodiment will be described below.

第1図は概略1′、!造工程図であり、第7図と同一部
分は同一符号で示しである。第1図において11はブレ
ークダウンスタンド3の入口に配置されたエツジ加熱用
の高周波誘導加熱装置である。この高周波誘導加熱装置
11は、第2図に示すような形状のワークコイルI2を
備えており、このワークコイル12には帯鋼2のエツジ
2a、2hのみを加熱するためのコイル部12a、12
bが設けられている。
Figure 1 is approximately 1',! This is a manufacturing process diagram, and the same parts as in FIG. 7 are indicated by the same symbols. In FIG. 1, reference numeral 11 denotes a high-frequency induction heating device for edge heating arranged at the entrance of the breakdown stand 3. This high-frequency induction heating device 11 is equipped with a work coil I2 having a shape as shown in FIG.
b is provided.

アンコイラ1から送り出された帯鋼2は、まず高周波誘
導加熱装置11によって両エッソ2a、2bが連続的に
加熱される。加熱範囲は板幅方向に厚さの1〜3倍程度
で十分であり、加熱温度は300〜1200℃の範囲で
行なわれる。このように、成形前の加熱は帯鋼2の全体
を加熱オろ必要(Jなく、エツジ2a、2bのみを加熱
すればよいが、全体を加熱した方がよい場合には、第3
図に示すようなワークコイル14を備えた高周波誘導加
熱装置13を併設すればよい。第4図は、このような加
熱処理による厚さ9mmの帯鋼2の幅方向の温度分布の
一例を示すものであり、(a)図は〆晶間域(600℃
)加熱、(b)図は熱間域(+000°C)加熱の場合
をそれぞれ示す。各図において、実線はエツジ加熱、破
線は全体加熱の場合を示している。
The steel strip 2 sent out from the uncoiler 1 is first heated continuously by the high frequency induction heating device 11 in both the escos 2a and 2b. It is sufficient that the heating range is about 1 to 3 times the thickness in the width direction of the plate, and the heating temperature is in the range of 300 to 1200°C. In this way, it is necessary to heat the entire steel strip 2 before forming (it is sufficient to heat only the edges 2a and 2b, but if it is better to heat the entire strip, the third
A high-frequency induction heating device 13 equipped with a work coil 14 as shown in the figure may be installed. Figure 4 shows an example of the temperature distribution in the width direction of the steel strip 2 with a thickness of 9 mm after such heat treatment.
) Heating, and (b) shows the case of heating in the hot region (+000°C), respectively. In each figure, solid lines indicate edge heating, and broken lines indicate whole heating.

このようにして加熱処理された帯鋼2は、ブレ−クダウ
ンスタンド3、フィンパススタンド4等のフォーミング
ロール群を順次通過し、少しずつ曲げ加工されて最後に
ほぼ管状の管状素管5となる。このロール成形は、帯鋼
2が温間あるいは熱間加熱されて冷間強度の約1/2程
度に低下しているので、エツジ2a、2b部分の曲げ加
工も容易に行なわれ、また残留応力も低減される。
The steel strip 2 heat-treated in this way sequentially passes through a group of forming rolls such as a breakdown stand 3 and a fin pass stand 4, where it is bent little by little and finally becomes a substantially tubular raw pipe 5. . In this roll forming, the steel strip 2 is warmly or hot heated and its cold strength is reduced to about 1/2, so bending of the edges 2a and 2b is easily performed, and the residual stress is also reduced.

次に、この管状素管5となった帯鋼のエツジ2a。Next, the edge 2a of the steel strip that became this tubular blank pipe 5.

2bを高周波誘導加熱装置6で加熱し、両エツジ2 a
、2 bをつき合わせてスクイズロール7によりアプセ
ットを行い、接合して電縫管8とする。この時、管状素
管5が既に高周波誘導加熱装置IIによって予熱されて
いるので、高周波誘導加熱装置6による加熱昇温は速く
なり、加熱に要する電力も少なくてすむ。
2b with a high frequency induction heating device 6, both edges 2a
, 2b are butted together and upset with a squeeze roll 7, and then joined to form an electric resistance welded tube 8. At this time, since the tubular blank 5 has already been preheated by the high-frequency induction heating device II, the heating temperature by the high-frequency induction heating device 6 becomes faster, and less power is required for heating.

こうして得られた電縫管8は、ブレークダウンでのエツ
ジ成形が容易であり、フィンパスでの成形強化による端
面形状の修正が十分になされ、また外面ブレが低減され
て、真円度の高いものとなっており、内面ビード切削に
要する手間も削減される。実験によると、従来困帷であ
ったt/D≧0゜16の厚内管の場合でも良好な結果が
得られている。また高周波電力も全体としてはむしろ低
減される傾向となり、更に溶接部の熱影響の幅が均一化
されて母材部分との硬度差が少なくなって、第5図及び
第6図に示すように、溶接部の品質が向」ニする。すな
わち、第5図及び第6図は従来例と本実施例の溶接部の
比較例であり、第5図(a)は従来例、同図(b)は本
実施例の熱影響部をそれぞれ示している。Aはつき合わ
せ部、斜線で示したBは熱影響部であって、各部の寸法
を図示のように表すと、いずれもa<a’、b<b”と
なっている。
The thus obtained electric resistance welded tube 8 has easy edge forming during breakdown, the end face shape is sufficiently corrected by strengthening the forming at the fin pass, outer surface wobbling is reduced, and the roundness is high. This reduces the effort required for cutting the inner bead. According to experiments, good results have been obtained even in the case of thick tubes with t/D≧0°16, which has been difficult in the past. In addition, the high-frequency power tends to be reduced overall, and the width of the thermal influence of the welded part is made uniform, and the difference in hardness with the base metal part is reduced, as shown in Figures 5 and 6. , the quality of welded parts will improve. That is, FIGS. 5 and 6 are comparative examples of the welded parts of the conventional example and this embodiment, and FIG. 5(a) shows the heat affected zone of the conventional example, and FIG. It shows. A is an abutting part, and B shown with diagonal lines is a heat affected zone, and when the dimensions of each part are expressed as shown in the figure, a<a', b<b'' in both cases.

また、第6図は溶接部の硬度を示しており、破線は従来
例、実線は本実施例である。この図から、母材部分と溶
接部の最大硬度との差をそれぞれC9C°とすると、c
>c’となっていることがわかる。
Moreover, FIG. 6 shows the hardness of the welded part, where the broken line is the conventional example and the solid line is the present example. From this figure, if the difference between the maximum hardness of the base metal part and the welded part is C9C°, c
>c'.

なお、−■二記実施例で帯鋼2の両エツジ2a、2bの
加熱温度を300〜1200°Cに限定した理由は次の
通りである。すなわち、温熱間加工による変形能(曲げ
加工性)は、一応の目安として(温間ロール成彩ては)
、静的高温引張試験である程度代表されろ。第9.In
、11図は炭素鋼による例である。鋼種によって多少の
変動はあるが、300℃までは引張強さは若干増加し、
伸び、絞りは減少する。300 ’C以上では引張強さ
は減少し、伸び、絞りは増加する傾向にある。このこと
より、3008C以上で加熱、加工ずろことにより変形
能(」向1−することが判る。したがって、300°C
以1−に限定した。また、加熱温度を−1−げろと効果
はあるか、第9〜11図に図示しているように、8(]
0〜900℃以上では引張強ざが急激に減少し、伸び、
絞りは増加する。また1200°C以上では加熱温度に
対しそれほど効果がなく、またスケールの発生が多いこ
とより、l−限を1200℃とした。
The reason why the heating temperature of both edges 2a and 2b of the steel strip 2 was limited to 300 to 1200°C in the second embodiment is as follows. In other words, the deformability (bending workability) due to warm working is a rough guide (after warm rolling).
, to some extent represented by static high-temperature tensile tests. 9th. In
, 11 shows an example using carbon steel. Although there is some variation depending on the steel type, the tensile strength increases slightly up to 300℃,
Elongation and aperture decrease. At temperatures above 300'C, tensile strength tends to decrease while elongation and reduction of area tend to increase. From this, it can be seen that heating and processing at temperatures above 3008°C improve deformability (1-). Therefore, at 3008°C
The following is limited to 1-. In addition, as shown in Figures 9 to 11, whether there is an effect by increasing the heating temperature by -1 - 8 (]
At temperatures above 0 to 900°C, the tensile strength decreases rapidly, elongation,
Aperture increases. Moreover, since heating temperature is not so effective at 1200°C or higher and scale is often generated, the l-limit was set at 1200°C.

〈発明の効果〉 以上述へたように、本発明の厚肉電縫管の製造方法は、
帯鋼の両エツジをあらかじめ加熱した後、ロール成形す
るものであり、エツジ部分の成形が容易で無理なく行な
われろため、管外径に対して板厚が比較的大きな厚肉電
縫管でも真円度の高い加工が容易となる。従って真円度
が高く、内面ヒートの切削か容易であり、溶接部の溶接
品質がすぐれた厚肉電縫管を容易に製造することができ
ろ。
<Effects of the Invention> As mentioned above, the method for manufacturing a thick-walled electric resistance welded pipe of the present invention has the following effects:
Both edges of the steel strip are heated in advance and then roll-formed, and the edge portions can be easily and effortlessly formed, so even thick-walled ERW pipes with a relatively large plate thickness relative to the outside diameter of the pipe can be straightened. Machining with high roundness becomes easy. Therefore, it is possible to easily manufacture a thick-walled electric resistance welded pipe with high roundness, easy cutting of the inner surface, and excellent welding quality at the welded portion.

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

第1図は本発明の一実施例の概略製造工程図、第2図(
a)はエツジ加熱用高周波誘導加熱装置の概略正面図、
同図(b)は同装置のワークコイルの斜視図、第3図(
a)は全体加熱用高周波誘導加熱装置の概略斜視図、同
図(b)は同装置のワークコイルの正面図、第4図(a
) 、 (b)はそれぞれ帯鋼の温度分布を示す図、第
5図(a)はiIL来例の溶接部の断面図、同図(h)
ij本発明による溶接部の断面図、第6図は溶接部の硬
度分布を示す図、第7図は従来例の概略製造工程図、第
8図は従来例による電縫管の断面図、第9図は各種鋼材
の引張り強さとl晶度の関係を示す図、第1O図は各種
網1の伸びと温度の関係を示す図、第11図は各種網+
Aの絞りと温度との関係を示す図である。 2・・帯鋼、2a、2b・エツジ、8・・・電縫管、1
1〜7− ・エツジ加熱用高周波誘導加熱装置、12・ワークコイ
ル。 特許出願人  株式会社 神戸製鋼所 代 理 人  弁理士 前出 葆 外2名第 第6図 、!1τ1・・・・ ノ橘す (b) (b) 撹刑 C>C
Figure 1 is a schematic manufacturing process diagram of an embodiment of the present invention, and Figure 2 (
a) is a schematic front view of a high frequency induction heating device for edge heating;
Figure 3 (b) is a perspective view of the work coil of the same device, and Figure 3 (
4(a) is a schematic perspective view of a high-frequency induction heating device for overall heating, FIG. 4(b) is a front view of the work coil of the same device, and FIG.
) and (b) are diagrams showing the temperature distribution of the steel strip, Figure 5 (a) is a cross-sectional view of the welded part of the iIL conventional example, and Figure 5 (h) is a diagram showing the temperature distribution of the steel strip.
ij Figure 6 is a cross-sectional view of a welded part according to the present invention; Figure 6 is a diagram showing the hardness distribution of the welded part; Figure 7 is a schematic manufacturing process diagram of a conventional example; Figure 8 is a cross-sectional view of an electric resistance welded pipe according to a conventional example; Figure 9 is a diagram showing the relationship between tensile strength and crystallinity of various steel materials, Figure 1O is a diagram showing the relationship between elongation and temperature of various nets 1, and Figure 11 is a diagram showing the relationship between various nets +
It is a figure which shows the relationship between the aperture of A and temperature. 2... Steel band, 2a, 2b, edge, 8... ERW pipe, 1
1 to 7- - High frequency induction heating device for edge heating, 12 - Work coil. Patent Applicant Kobe Steel Co., Ltd. Agent Patent Attorney 2 people including the above-mentioned person Figure 6,! 1τ1... No Tachibanasu (b) (b) Agitation C>C

Claims (2)

【特許請求の範囲】[Claims] (1)帯鋼を連続的にロール成形しながら、そのエッジ
のつき合わせ部を溶接する厚肉電縫管の製造方法におい
て、 上記帯鋼の両エッジをロール成形前にあらかじめ加熱す
ることを特徴とする厚肉電縫管の製造方法。
(1) A method for manufacturing a thick-walled electric resistance welded pipe in which a steel strip is continuously roll-formed and the abutting portions of the edges are welded, characterized in that both edges of the steel strip are preheated before roll-forming. A method of manufacturing a thick-walled electric resistance welded pipe.
(2)特許請求の範囲第1項記載の厚肉電縫管の製造方
法において、 上記帯鋼の厚さtと成形後の管外径Dの比t/Dが0.
16以上であり、帯鋼の両エッジの加熱温度が300乃
至1200℃である厚肉電縫管の製造方法。
(2) In the method for manufacturing a thick-walled electric resistance welded pipe according to claim 1, the ratio t/D between the thickness t of the steel band and the outside diameter D of the pipe after forming is 0.
16 or higher, and the heating temperature of both edges of the steel strip is 300 to 1200°C.
JP18254285A 1985-08-19 1985-08-19 Manufacture of thick wall electric welded tube Pending JPS6240935A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP18254285A JPS6240935A (en) 1985-08-19 1985-08-19 Manufacture of thick wall electric welded tube

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP18254285A JPS6240935A (en) 1985-08-19 1985-08-19 Manufacture of thick wall electric welded tube

Publications (1)

Publication Number Publication Date
JPS6240935A true JPS6240935A (en) 1987-02-21

Family

ID=16120108

Family Applications (1)

Application Number Title Priority Date Filing Date
JP18254285A Pending JPS6240935A (en) 1985-08-19 1985-08-19 Manufacture of thick wall electric welded tube

Country Status (1)

Country Link
JP (1) JPS6240935A (en)

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