JPH067944A - Manufacture of pipe - Google Patents

Abstract

PURPOSE:To manufacture a pipe excellent in quality and dimensional precision by superposing welding joints, holding the joints with a holding jig and welding with a plasma torch. CONSTITUTION:A metallic plate 3 is made round to manufacture the pipe 4. Therefore, at the position of a welding groove 1 in the longitudinal direction of the upper surface center of a flat welding jig 2, after welding joints 5, 5' for manufacturing a pipe 4 are superposed, the welding is executed by moving a plasma torch 7 positioned to the prescribed height from the welding joints 5, 5' by holding a holding jigs 6, 6' with prescribed speed. Then, the uniform and stable welding can be executed so that the part to be welded is hardly deviated or separated from the center of plasma torch 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding method for forming a pipe by rolling a plate material, and more particularly to a method for manufacturing a pipe suitable for assembling equipment in a glass-ceramic industry apparatus.

[0002]

2. Description of the Related Art Conventionally, in order to weld an end face of a pipe, as shown in FIG. 3, a plate material 3 is rounded and formed at a position of a welding groove 1 in a central longitudinal direction of an upper surface of a flat welding jig 2 to form a pipe. To hold the welded joints 5 and 5'for making
The pipe 4 was obtained by holding at 6'and welding with the plasma torch 7 using the welding rod 8.

By the way, in such a welding method, the abutting portion may be displaced from the center of the plasma torch 7 in the longitudinal direction or the abutting portion may be displaced due to expansion and contraction of the welded portion due to melting and solidification, and linearity of the welded joint. If they are separated, welding failure will occur. Further, it is difficult to supply an appropriate welding rod to the welded part. Such a phenomenon becomes more prominent as the length of the pipe 4 to be welded increases.

[0004]

SUMMARY OF THE INVENTION Therefore, the present invention provides a method for producing a pipe which allows uniform and stable welding without the welded portion for producing the pipe being displaced or separated from the center of the plasma torch. Is what you are trying to do.

[0005]

The pipe manufacturing method of the present invention for solving the above-mentioned problems is to roll a plate material by rolling a plate material at the position of the welding groove in the central longitudinal direction of the upper surface of a flat welding jig. It is characterized in that welded joints for making are piled up and held by a holding jig and welded by a plasma torch.

[0006]

As described above, in the pipe manufacturing method of the present invention, since the welded joints are overlapped and welded, it is possible to perform uniform and stable welding without supplying a welding rod even if the welded joints are slightly misaligned. It will be.

[0007]

EXAMPLE An example of the manufacturing method of the present invention will be described with reference to the drawing. As shown in FIG.
Width 32mm, length 515m with groove 1 for m and depth 2mm
An outer diameter of a Pt plate 3 having a thickness of 0.34 mm, a width of 220 mm and a length of 300 mm is set on the upper surface of a welding jig 2 made of brass and having a height of 24 mm and a diameter of 7 mm.
Welded joint 5 for forming pipe by rounding to 0 mm
After stacking 5 ', the plasma torch 7 held by the holding jigs 6, 6'and positioned at a height of 3.5 mm from the welding joints 5, 5'is moved at a speed of 5 mm / sec for welding. Then, a pipe 4'as shown in FIG. 2 was obtained.

However, in the conventional butt-welding method for plate materials, as shown in FIG. 3, the welding jig 2, the pressing jigs 6 and 6 ', and the plate material 3 having the same size and shape as those of the embodiment are rounded to an outer diameter of 70 mm. , Welded joints 5 and 5'for making the pipe 4 are butted and welded by migrating the plasma torch 7 at a speed of 5 mm / sec by using a welding rod 8 having a material Pt and a wire diameter of 0.7 mm under the same conditions as the embodiment. Then, the pipe 4 was obtained.

As a result of the above, in the conventional example, as shown in FIG. 4, the butt-welded portion has a hole in which the butt-faced surface is misaligned, or the welding width is not uniform. Whereas, in the example, the welded part is displaced from the center of the plasma torch,
Even if they did not come apart, uniform and stable welding was possible.

[0010]

As described above, according to the pipe manufacturing method of the present invention, since the welded joints are overlapped and welded, even if there is a slight deviation in the welded joints without supplying a welding rod, it is stable and uniform. It has an excellent effect that a pipe that can be welded and has excellent quality and dimensional accuracy can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which welded joints are overlapped and held by a holding jig in an embodiment of a pipe manufacturing method of the present invention.

FIG. 2 is a perspective view showing a welded state in an embodiment of the pipe manufacturing method of the present invention.

FIG. 3 is a perspective view showing a state in which a welded joint is butted and held by a holding jig in a conventional pipe manufacturing method.

FIG. 4 is a perspective view showing a state of a pipe after welding in a conventional pipe manufacturing method.

[Explanation of symbols]

 1 Welding groove 2 Welding jig 3 Plate material 4'Pipe 5, 5'Welding joint 6, 6'Holding jig 7 Plasma torch

Claims (1)

[Claims] 1. A plasma torch that holds a welding joint for rolling a plate material to form a pipe at a position of a welding groove in the center longitudinal direction of an upper surface of a flat welding jig and holding the welding joint with a holding jig. A method for manufacturing a pipe, which comprises welding by welding.