JPS6325878B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of arc welding a cylindrical metal body.

Conventionally, welding speeds cannot be increased when welding cylindrical or prismatic cans with a plate thickness of approximately 0.2 to 0.5 mm;
The heat affected zone due to the arc is larger than that of seam welding, and high butt accuracy is required.
Arc welding is rarely used because the arc tends to be drawn to the edges and the end face of the weld is likely to burn off, so seam overlap welding is generally used. However, this method involves overlapping the joints, sandwiching the overlap between roller electrodes from above and below, and applying an AC voltage between the electrodes to fuse the base materials with Joule heat, which reduces machine costs. Expensive, discoloration of heat affected zone,
The disadvantage is that secondary processing of the overlapping portion is difficult. However, in recent years, high-frequency pulsed arc welding methods have been developed, and the welding speed (as described above) and end face treatment technology (as described above) have been improved, so the application of arc welding methods has been reconsidered. However, there were still problems with the heat-affected zone of the arc (above) and the butt accuracy (above). That is, in the conventional arc welding method, as shown in FIG. 1, the joints to be welded are butted together at an upper position, and welding is performed by applying an arc from above (towards the outer surface of the can). Therefore, it is difficult to precisely match the seam lines and to match the seam lines and weld lines accurately, and because cylindrical metal bodies are often used as products with their outer surfaces intact, discoloration, The disadvantage was that the damage to the paint greatly affected the aesthetic appearance.

An object of the present invention is to provide a method for welding a cylindrical metal body by stable arc welding, which can solve these problems all at once.

EMBODIMENT OF THE INVENTION Hereinafter, the structure and operation of the present invention will be explained in detail with reference to illustrated embodiments. FIG. 2 is a front view showing the basic configuration of the present invention. In the figure, 1 indicates the can to be welded, and 2 and 2 indicate the tips of the parts to be welded, respectively. 3
indicates a flat table. That is, with the welded joint parts 2 and 2 of the canned goods 1 facing downward and pressed onto the flat surface of the flat table 3 from above, left, and right, one joint end 2 and the other joint end are pressed. 2 and welded from the inner surface side (back side) of the can 1. In this way, since the joining tips are aligned on a plane and abutted, misalignment during abutting as shown in FIG. 3 does not occur, and the abutting can be performed extremely easily and accurately. Furthermore, since welding is performed from the back side, the finish on the front side of the can is extremely beautiful, and even if the surface is painted, there is very little chance of damaging the paint. FIG. 4 is an explanatory diagram illustrating a method of aligning both ends of the joint with the weld line and butting the weld line. In the figure, 1 is the can to be welded, 2 and 2 are the butt ends of the can, 3 is a flat table, and 4
is a seam guide that can be taken out and put in on the flat table 3,
5 and 6 are club mechanisms that clamp the tip of canned goods;
It is. First, as shown in FIG. 4A, with the seam guide 4 aligned with the welding line and put out on the flat table, the butt end 2 on one side of the canned goods 1 is aligned with the plane of the flat table 3, and the seam guide 4 2 and align the tip 2 with the welding line. In this state, a portion of the can 7 on the tip 2 side is clamped on a flat table by a clamping mechanism 5 at a position away from the tip 2 to an extent that does not hinder welding. Next, after inserting the seam guide 4 under the flat table as shown in FIG. It abuts against the tip 2 already clamped on the welding torch line, and is clamped on a flat table by a clamping mechanism 6 at a position away from the tip 2 to an extent that does not hinder welding. (Note: The blank space on the plane caused by placing the seam guide 4 under the plane table can be made without any problem by using several small guide pins as seam guides if necessary.) In this state, with the welding torch 7, The butt portions are welded. Therefore, according to this method, the abutting portion can be easily aligned with the welding line, and since both ends are abutted while being pressed on a flat surface,
This eliminates the possibility of mismatching.
FIG. 5 is a configuration diagram showing an example of a jig for implementing the welding method of the present invention. In the figure, 1 is the can to be welded, 3 is a flat table, 4 is a seam guide, 5 and 6 are clamp mechanisms, 7 is a welding torch, and 8 is a device that applies appropriate pressure to the can from the left, right, and top, respectively. This is a fixed frame to which pressure mechanisms 9, 10, and 11 are attached. That is, the canned food 1 is inserted into the inside of these three pressure mechanisms with no pressure from the pressure mechanisms 9, 10, and 11, and with the seam guide 4 exposed on the flat table 3, the left pressure mechanism 9 and the upper After applying pressure to the canned goods 1 with the pressure mechanism 11 and pressing the left butt end against the seam guide, only the left side is moved to the clamp mechanism 5.
Clamp with. Then, after putting the seam guide 4 under the flat table 3, pressure is gradually applied to the canned food 1 by the right pressure mechanism 10, the right side butting tip 2 butts the left side tip 2, and the clamping mechanism 6 clamps it. Arc welding is performed from the inside of the can along the weld line. Therefore, butting during welding can be carried out easily and accurately, and although conventional seam welding methods required removal of paint from the welded area of about 5 mm width, welding can be performed from the inside surface. As a result, there is less heat influence on the outer surface of the cylindrical metal body, and the area where the paint is removed can be narrowed to about 2 mm width. Also, depending on the application, it may not be necessary to produce an uranami beat. In this case, it becomes possible to eliminate the parts to be painted, and at the same time, the welding finish becomes extremely beautiful. Arc welding also overcomes the drawbacks of conventional seam welding methods, such as high machine costs, discoloration of the heat-affected zone (discoloration is prevented with gas shielding in arc welding), and difficulty in secondary processing due to overlapping. This will bring about the excellent effect of eliminating both problems.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the direction of the can in the conventional arc welding method, Fig. 2 is a front view showing the basic configuration of the present invention, Fig. 3 is a view showing an example of misalignment during butt, Fig. 4 5 is an explanatory diagram showing a method for butting the butt portions to match the welding line when the welding line is determined, and FIG. 5 is a configuration diagram showing an example of a jig for carrying out the welding method of the present invention. .

Claims (1)

[Claims] 1. When welding a cylindrical or prismatic short pipe 1, a removable seam guide 4 is provided on a part of the plane 3, and the short and long pipe 1 is welded with the seam guide 4 exposed above the plane 3. With one side 2 of the butt part facing downward, press it against the seam guide 4 along the plane 3 and align it on the weld line, then clamp it, and then put the seam guide under the plane 3. , the other side 2 of the abutting part is pressed against the tip of the clamped side 2 along the plane 3 and clamped, and after abutting on the weld line, the abutting part is removed from the inner surface of the cylinder or rectangular tube. Arc welding method for cylindrical metal bodies to be welded.