JPH10192964A - Laser beam tube welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam tube welding method which is simple, has a well workability and easily obtains a high welding quality without requiring a special composition of a conventional heating means for closely attaching butt parts except its forming means to form a metal plate as the raw material in a tube like. SOLUTION: A tube welding is executed in a tube forming process (1) where a metal plate 1 as a raw material is formed in a tube like and its both end parts are put in the butt state same as at welding or the proximate state, a laser cutting process (2) where respective end parts are cut parallel to the welding face with a laser beam, a butt process (3) where these cutting faces are again butted, and a laser beam welding process (4) where these butt parts are welded with the laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser pipe welding method for manufacturing a pipe by forming a plate of various metals into a pipe shape and welding a butt portion using a laser beam.

[0002]

2. Description of the Related Art In this type of laser pipe welding,
Since the processing accuracy of the end face of the plate material 101 directly affects the butted portion when the plate material 101 as a raw material is formed into a pipe shape, the gap Sa is formed as shown in FIG. The required energy density increases, and it becomes necessary to increase the output of the laser oscillator or reduce the welding speed, which not only reduces workability but also has a significant effect on welding quality. . Therefore, as shown in FIG. 5, the butting portion of the plate material 101 is heated by the heating means 102 and the pressing means 10
A method is known in which welding is performed with a laser beam L in a state where the butt portions are brought into close contact with each other by pressing from both sides via the third and the third 104 as shown in FIG. However, this conventional technique has a problem in that not only the heating means is required in addition to the pressing means, but also the swelling portion 105 is easily formed at the butting portion.

As for laser welding between flat plates, there is known a laser welding method in which the ends of the respective materials are cut in advance and the ends are butted and welded (Japanese Unexamined Patent Publication No. 61-61605). 276790, JP-A-4-3
No. 27388). However, when this conventional technique is applied to the case of pipe welding, when both ends of a flat plate-shaped material are cut in advance and then formed into a pipe shape, as shown in FIG. Although not as large as the gap Sa, the gap Sb may be formed, or there may be cases where distortion occurs during molding into a pipe shape and the joining surfaces are not aligned and cannot be in close contact with each other. However, the workability and welding quality were still adversely affected.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional technical circumstances, and an object of the present invention is to provide a forming means for forming a plate material as a raw material into a pipe shape. In addition, there is no need for a special configuration such as a heating means for contacting the butt portion, and a laser pipe welding method that is simpler, has good workability, and can easily obtain high welding quality. It is in.

[0005]

According to the present invention, in order to solve the above-mentioned problems, a plate material, which is a raw material, is formed into a pipe shape, and both ends thereof are placed in a butt state or a close state similar to that at the time of welding. After each end was cut in parallel with the welding surface by laser light, the cut surfaces were butted again, and the butted portion was welded by laser light.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention can be widely applied without being influenced by a concrete forming method for forming a plate material as a pipe into a pipe shape.
That is, a batch forming method of intermittently forming a pipe shape by bending using a plate material cut to a predetermined length as a material, or a continuous forming method of continuously forming a pipe shape by a so-called roll forming method. Applicable to things. In short, whether intermittent or continuous, a plate material is formed into a pipe shape, and both ends of the plate material are placed in the same butted or close state as when welding, and each end is As long as the portion can be laser-cut, application is possible. The pipe shape is not limited to a circular shape, but may be a square shape or the like. Regarding the number of laser beam irradiation nozzles, in the case of the former batch molding method, a laser cutting irradiation nozzle and a laser welding irradiation nozzle may be separately provided, but laser output and the like may be provided. It is also possible to configure so that one irradiation nozzle is shared and the irradiation operation is repeatedly performed by adjusting. On the other hand, in the case of the latter continuous molding method, the irradiation operation is performed at a fixed position using two irradiation nozzles for laser cutting and one irradiation nozzle for laser welding, respectively. Is appropriate. The welding section is not limited to the radial direction of the pipe, but may be inclined. In that case, the cut surface of the laser cutting is also inclined according to the welding cross section.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view showing an outline of the flow of the working process of the present invention, and FIG. 2 is a schematic configuration showing a main part when applied to a continuous forming method using a roll forming method as one embodiment. FIG. As shown in FIG. 1, the working process of the present invention includes (1) a pipe forming process, (2) a laser cutting process, (3) a butting process, and (4) a laser welding process. First, in the pipe forming step of the step (1), a metal plate 1 as a raw material is formed by using a number of sets of forming rolls 2 and 3 illustrated in FIG. Molded into a pipe according to the law,
The two ends are placed in the same butted or close state as in welding. Thereafter, the process proceeds to the laser cutting step of step (2), and a small amount necessary for shaping both ends in the abutting state or the close state is irradiated from the laser cutting irradiation nozzles 4 and 5 illustrated in FIG. Laser light L ₁ , L ₂ to cut off in parallel with the welding surface. In this case, an inert gas such as nitrogen gas or argon is used as an assist gas to prevent oxidation of the cut surface. However, when an iron-based steel material is used as the plate material 1, there is no particular problem because the oxide film formed is very thin even if oxygen gas is used. Further, in the butting step of the step (3), the cut surfaces are butted again by an appropriate means while using a jig or the like for holding down, and both surfaces are brought into close contact with each other. Then, in the laser welding step of step (4), continuous by the laser beam L ₃ emitted from the irradiation nozzle 6 for laser welding illustrated in FIG. 2 with respect to the abutting portion of the cutting surface which is in its close contact Welding is performed. In this case, an inert gas such as helium or argon or a carbon dioxide gas is used as a shielding gas for laser welding. Thus, by continuously performing the above steps (1) to (4), the target pipe is continuously manufactured.

FIG. 3 is a schematic structural view showing a main part of another embodiment of the present invention when applied to the above-mentioned batch forming method of forming a pipe intermittently. In this embodiment, the plate 7 is cut in advance to a predetermined length as a raw material, and the plate 7 is bent into a pipe shape in the pipe forming step of the step (1), and as shown in FIG.
A forming member 10, which is driven through appropriate driving means 8, 9 including a two-stage hydraulic cylinder or the like capable of performing two-stage forward movement,
11 is used to set two states, a butting or approaching state in the laser cutting step in the step (2) and a butting state in the laser welding step in the step (4).

In this embodiment, the plate member 7 is inserted between the forming members 10 and 11 at least at the final stage of forming into a pipe shape, and firstly the first-stage operation is performed via driving means 8 and 9. It is set to the abutting or approaching state in the laser cutting step of step (2). FIG.
Shows the set state. In this state, the laser light L emitted from the laser cutting irradiation nozzle 12 is shown.
₄ by cutting off the small amount required for shaping parallel to the weld surface. In this case, it is possible to prepare two irradiation nozzles and cut both ends of the plate material 7 at the same time.
The irradiation nozzle 12 may be used to cut one side at a time. When both ends of the plate member 7 are cut and shaped, the process proceeds to the butting step of step (3), and the forming members 10 and 11 are advanced to the second-stage operating position via driving means 8 and 9. Then, the gap formed by the cutting in the step (2) is filled, and both ends of the plate member 7 are again butted to be set to the butting state at the time of the laser welding in the step (4). Thereafter, laser welding is performed on the joint portion of the plate material 7. In this case, in laser cutting and laser welding, the type and amount of assist gas or shielding gas to be used as an auxiliary are selected and output. Since the same irradiation nozzle can be commonly used if adjusted, laser irradiation may be performed using the irradiation nozzle 12 in common, or laser irradiation may be performed by preparing a dedicated irradiation nozzle. It may be.

[0010]

According to the present invention, as described above, after a plate material as a raw material is formed into a pipe shape, both ends in an abutting state or a close state are cut in parallel with a welding surface by laser light. Since the cut surfaces are re-butted and laser-welded, an extremely good adhesion state can be obtained easily without heating or strongly pressing as in the past, thus improving workability. And high welding quality can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a flow of an operation process of the present invention.

FIG. 2 is a schematic configuration diagram showing a main part of an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a main part of another embodiment of the present invention.

FIG. 4 is a partially enlarged view showing a state of a conventional butting portion.

FIG. 5 is a schematic configuration diagram showing a main part of a conventional example.

FIG. 6 is a partially enlarged view showing a state of a butt portion during laser pipe welding in the conventional example.

FIG. 7 is a partially enlarged view showing a state of a butt portion at the time of laser pipe welding in another conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plate material, 2, 3 ... Forming roll, 4, 5 ... Irradiation nozzle for laser cutting, 6 ... Irradiation nozzle for laser welding, 7 ... Plate material, 8, 9 ... Driving means, 10, 11 ... Forming member

Claims (1)

[Claims] 1. A laser pipe welding method for forming a metal plate into a pipe shape and welding a butt portion thereof with a laser beam, wherein the plate material is formed into a pipe shape.
After placing both ends in the same butted state or close state at the time of welding, cutting each end in parallel with the welding surface by laser light, butting those cut surfaces again, and joining the butted portion A laser pipe welding method characterized by welding by a laser beam.