JP4388235B2 - Metal tube manufacturing method and apparatus - Google Patents

Description

【００１３】
【発明の効果】
以上詳述したように、本発明はＴＩＧ溶接を用いた金属管の凝固割れの発生を防止し、高速な溶接・造管を可能する金属管の製造方法を提供するものとして、工業上有益な効果をもたらし得るものである。
【図面の簡単な説明】
【図１】本発明の原理を説明する外観図であり、（ａ）は平面図、（ｂ）は金属管軸方向から見た図である。
【符号の説明】
１ 金属管
２ 前方ロール
３ 後方ロール
４ ロール（溶接押さえ上ロール）
５ 溶接用トーチ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing a metal pipe that does not have microcracks in a welded portion during TIG welding and enables high-speed welding.
The present invention is suitable for TIG welding of titanium and stainless steel, in which springback is a problem as a metal tube.
[0002]
[Prior art]
A conventional method for manufacturing a metal tube uses a multi-stage perforated roll and an apparatus for bending by forming from a coil in the circumferential direction. There is a forming stand that stably forms a weld called a squeeze roll during TIG welding. Conventionally, two opposed hole rolls are used in this roll in multiple stages and reduced in diameter to cope with high speed welding, but there is a limit to the pipe forming speed.
[0003]
According to Plasticity and Processing VOL. 29-334 (1988) (referred to as Reference 1), pipe outer diameter is 25.4mm with pipe diameter of 25.4mm using pure titanium material, using 4 stages of 2 roll squeeze rolls. A technique is disclosed in which the welding speed of the pipe making can be up to 8.3 m / min by setting the gap between the rolls to 70 mm and the roll interval to 70 mm.
In addition, as a conventional 4-split roll, for the purpose of preventing unevenness of tube rolling (stretch reducer), Japanese Patent Application Laid-Open No. 60-87907 (referred to as Reference 2) and the like A technique for changing the roll angle by 45 degrees is disclosed.
Further, as an application of a four-part roll to an electric resistance steel pipe, Japanese Patent No. 2520538 (referred to as Reference 3) and the like are disclosed regarding drawing forming that increases the roundness of the pipe end.
[0004]
[Problems to be solved by the invention]
However, although the technique described in Reference Document 1 states that the welding speed can be up to 8.3 m / min, there is a problem that the welding speed cannot be increased beyond this. In addition, the invention disclosed in Reference Document 2 is not aimed at shortening the roll interval or metal pipe welding, and cannot improve the welding speed. Further, the invention disclosed in Reference 3 is also aimed at equalizing the residual stress of the pipe in the molding after welding, and is different from the present invention which improves the welding speed.
An object of this invention is to provide the manufacturing method and manufacturing apparatus of a metal pipe which enable the high-speed welding of a TIG welded pipe in which a buckling becomes a problem in the shaping | molding at the time of welding.
[0005]
[Means for Solving the Problems]
That is, the gist of the present invention is as follows. (1) In a method of rolling a flat plate into a cylindrical shape and manufacturing a metal pipe by TIG welding, after welding the cylindrical ends to each other, welding to the pipe making shaft Rotate 45 degrees from the part, and rotate the front roll divided into four parts, and rotate 90 degrees from the welded part to the tube-forming axis behind it, making the roll interval with the front roll smaller than the roll outer diameter, and dividing into four parts. A method of manufacturing a metal tube, wherein the metal tube is restrained by a rear roll.
(2) The method for producing a metal pipe according to (1), wherein the roll hole mold disposed in the welded portion of the rear roll has a groove so as not to contact the welded portion.
(3) The method for producing a metal pipe according to (1) or (2), wherein the weld is further TIG welded between a front roll and a rear roll,
(4) In an apparatus that roll-forms a flat plate into a cylindrical shape and manufactures a metal pipe by TIG welding, after the first welding electrode in the pipe making direction, the pipe is rotated 45 degrees from the welded part with respect to the pipe making axis and divided into four. The front roll is arranged, rotated 90 degrees from the welded portion with respect to the tube-forming axis behind the roll, the roll interval with the front roll is made smaller than the outer diameter of the roll, and the rear roll has four parts. Metal pipe manufacturing equipment,
(5) The metal tube manufacturing apparatus according to (4), wherein the roll hole mold disposed in the welded portion of the rear roll has a groove so as not to contact the welded portion.
(6) The apparatus for manufacturing a metal pipe according to (4) or (5), wherein a second welding electrode for welding the welded portion is disposed between the front roll and the rear roll.
It is in.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
FIG. 1 shows a molding method according to an embodiment of the present invention. Around the metal tube base plate 1 before welding, a front roll 2 that is rotated 45 degrees from the welded portion to the left and right with respect to the pipe making shaft and divided into four parts is arranged, and behind these front rolls 2 and 90 degree pipe making A rear roll 3 is arranged so as to intersect the axis. In other words, the rear roll 3 is rotated 90 degrees from the welded portion with respect to the pipe making shaft. However, among the rear rolls 3, the roll 4 disposed on the welded portion uses a roll 4 in which the roll is grooved so as not to come into contact with the welded portion that is in a molten state during high-speed welding. However, this groove is not necessary when the welded portion and the rear roll come into contact after the welded portion is in a solid state.
[0007]
In the pipe forming direction (metal pipe axial direction), the welding torch 5 is disposed only in front of the front roll 2 or, if necessary, a second welding electrode is disposed in front of the rear roll 3 for further high-speed welding. If a roll is placed in front of the front roll, a third welding electrode is placed immediately below or in front of the roll, or if a roll is additionally placed after the rear roll, the welding press behind the rear roll 3 TIG welding may be performed by providing a third welding electrode behind the upper roll 4.
[0008]
That is, when the welding speed increases, the molten pool moves backward, and when the force that constrains the pipe (metal pipe) during solidification does not act, solidification cracks occur in the weld and Don't be. Therefore, the present inventors can reduce the difference between the roll bottom diameter and the roll flange diameter, reduce the difference in peripheral speed generated between the roll and the pipe, increase the pipe making speed, In the rear roll 3 intersecting with the roll 2 by 90 degrees, the distance between the front roll 2, the rear roll 3 and the pressing roll 4 is made smaller than that of the conventional two rolls, and once the tube is formed by spring back in the circumferential direction near the solidification point. It has been found that the occurrence of solidification cracking can be prevented by suppressing the opening of the tube after the opening.
[0009]
In the present invention, it is possible to make the roll outer diameter DR larger than the roll interval L (DR> L), which was impossible with the conventional two rolls. By bringing the front roll and the rear roll close to each other, even a metal pipe such as a titanium pipe that is easily spring-backed can be welded at high speed without solidification cracking. In addition, the rear roll 3 and the welding presser upper roll 4 to be installed as necessary are provided with a mechanism for moving backward when the pipe making speed becomes higher.
[0010]
【Example】
Table 1 shows the relationship between the welding speed and the solidification cracks in the weld when welding is performed using the conventional method and the present invention. TIG welding was performed on a tube made of pure titanium with an outer diameter of 25.4 mm and a plate thickness of 0.7 mm. In the example of the present invention, the first torch is 10 mm in front of the front roll and the second torch is 20 mm in front of the rear roll. The outer diameter of the front roll and the rear roll divided into four parts is 42 mm. As shown in FIG. 1, the front roll and the rear roll are rotated 45 degrees from the welded portion with respect to the tube-forming axis, and the rear roll is 90 degrees from the welded portion with respect to the tube-forming shaft 40 mm behind the front roll. Rotated and placed. A groove having a depth of 3 mm and a width of 5 mm was installed in the roll that hits the upper part of the welded portion of the rear roll 3. Although two torches were used for welding, two or more torches may be used.
[0011]
In the comparative example, a comparison was made between a case where two divided rolls were provided in front and rear with a roll interval of 150 and 70 mm and a case where the roll interval was 40 mm according to the present invention. In the comparative example, the position of the welding torch was the same as the example of the present invention. In the comparative example, a welding defect due to solidification cracking occurred at a welding speed of 8 m / min, but in the example of the present invention, welding of 10 m / min was possible. In addition, almost no appearance flaws occurred due to the peripheral speed of the roll.
[0012]
[Table 1]

[0013]
【The invention's effect】
As described in detail above, the present invention is industrially useful as a method of manufacturing a metal pipe that prevents the occurrence of solidification cracking of the metal pipe using TIG welding and enables high-speed welding and pipe forming. It can have an effect.
[Brief description of the drawings]
1A and 1B are external views for explaining the principle of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a view as seen from a metal tube axis direction;
[Explanation of symbols]
1 Metal tube 2 Front roll 3 Rear roll 4 Roll (welding presser upper roll)
5 Welding torch

Claims (6)

In a method of rolling a flat plate into a cylindrical shape and manufacturing a metal tube by TIG welding, after welding cylindrical ends, the front roll rotated 45 degrees from the welded portion with respect to the tube-forming shaft and divided into four Rotating 90 degrees from the welded portion with respect to the tube-forming shaft to the rear, making the roll interval with the front roll smaller than the outer diameter of the roll, and constraining the metal tube with the four-fold rear roll A method of manufacturing a metal tube. 2. The method of manufacturing a metal pipe according to claim 1, wherein the roll hole mold disposed in the welded portion of the rear roll has a groove so as not to contact the welded portion. The method of manufacturing a metal pipe according to claim 1 or 2, wherein the welded portion is further TIG welded between a front roll and a rear roll. In an apparatus for rolling a flat plate into a cylindrical shape and manufacturing a metal tube by TIG welding, the front roll is divided into four parts by rotating 45 degrees from the welded portion with respect to the tube-forming axis after the first welding electrode in the tube-forming direction. The metal pipe is provided with a rear roll divided into four parts by rotating 90 degrees from the welded portion with respect to the pipe making shaft at the rear, making the roll interval with the front roll smaller than the roll outer diameter. Manufacturing equipment. 5. The apparatus for manufacturing a metal pipe according to claim 4, wherein the roll hole mold disposed in the welded portion of the rear roll has a groove portion so as not to contact the welded portion. The metal pipe manufacturing apparatus according to claim 4 or 5, wherein a second welding electrode for welding the welded portion is disposed between the front roll and the rear roll.

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