JPS58122199A - Welding method of piping - Google Patents

Abstract

PURPOSE:To make automatic welding possible without filler metals and to make installation work easy by inserting two pipings respectively into the socket and spigot parts provided at both ends of a short pipe, melting the projecting parts provided on the outside circumferential surface of the short pipe and joining both pipings and the short pipe by melting. CONSTITUTION:A piping 3 consisting of an Al alloy of about 30mm. is interposed between two pipings 1 and 2 consisting of an Al alloy. Socket and spigot parts 4 are formed to both ends of the pipe 3 and the pipings 1, 2 are inserted thereon. Projecting parts 5 are formed in one body on the outside circumferential surface thereof. The outside diameter of the pipe 3 is made equal to the outside diameter of the pipings 1, 2 and the inside diameter thereof is made equal to or larger than the inside diameter of the pipings 1, 2. An automatic welding machine is so set that the preceding end of the torch thereof is located at the center of the projecting part 5 and the pipings 1, 2 are rotated to weld the pipings, whereby the pipings 1, 2 and the projecting parts 5 of the pipe 3 are thoroughly fused together to form a weld zone 6, and reinforcement of weld is assured.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a pipe welding method that facilitates on-site installation work.

(Technical background of the invention and its problems) Conventionally, welding methods have been used to connect pipes together, but the pipe welding method uses a butt method or sleeve method to butt the pipes together. has been done.

However, the former method requires a jig for beveling and aligning the pipes, and therefore the dimensional accuracy or installation error of the pipes must be strictly controlled.

In addition, the latter eliminates the need for beveling the piping and reduces the amount of eccentricity of the piping.
It has advantages such as dimensional accuracy of piping and alleviation of installation errors, but on the other hand, not only is the strength of welding insufficient, but also filler metal must be used when performing automatic welding, which increases the cost of the welding machine. There are disadvantages such as inheritance.

(Object of the Invention) The present invention has been made in order to eliminate the above-mentioned drawbacks, and its purpose is to effectively utilize the excellent advantages of the one-way butt type and sleeve type of connecting pipes,
Another object of the present invention is to provide a pipe welding method that enables automatic welding without filler metal, facilitates installation work on site, and allows adjustment of pipe dimensions.

(Summary of the Invention) That is, the present invention is characterized in that a convex portion and a spigot portion are formed on the outer peripheral surface of a short pipe interposed between one pipe and the other pipe, or on at least one of the pipes. The pipe welding method is characterized in that after bringing the pipe and the short pipe into close contact with the spigot part, the convex part is melted with a torch of a welding machine to fuse and connect both the pipes and the short pipe.

(Embodiment of the Invention) Hereinafter, an embodiment of the pipe welding method according to the present invention will be described with reference to the drawings.

FIG. 1 is a side view, partially in cross section, of a configuration for explaining the welding method according to the present invention.

That is, in order to join one pipe 1 made of M alloy and the pipe 2 made of M alloy, a short pipe 6 made of match metal and having a length of about 3011111 is interposed.

The short pipe 3 has spigot parts 4 formed at both ends for inserting the piping 1 and the piping 2, and a convex part 5 is integrally formed on the outer peripheral surface of the short pipe 3.

The outer diameter of the short pipe 3 is equal to the outer diameter of the pipes 1 and 2, and its inner diameter is the same or larger than the inner diameters of the pipes 1 and 2.

The size of the convex portion 5 is determined so as to ensure a surplus after welding.

FIG. 2 is a sectional view showing a process of welding the pipe 1.2 and the short pipe 6 using an automatic welding machine such as a TIG welding machine.

That is, after bringing the ends of the pipes 1 and 2 into close contact with the spigot part 4 of the short pipe 6, set the automatic welding machine's torch so that the tip is located in the center of the convex part 5, and weld by rotating the torch or the pipes. Do the following.

The cross section after welding is shown in the right half of Fig. 2, where the welded part 6
In this case, the convex portions of the pipe 2 and the short pipe 3 are completely fused, and the excess buildup is ensured.

Therefore, this welded joint can obtain strength equivalent to that of the base metal.

(Effects of the Invention) As described above, by using the pipe welding method according to the present invention, the strength of butt welding is excellent, the sleeve method does not require beveling, and the dimensional accuracy and installation error of the pipe can be reduced. It has the advantage of making use of the benefits of relaxation, and also enables automatic welding without the need for filler metal.

In addition, when repairing holes in welded φ piping or when the spacing between pipe ends becomes excessive due to accumulation of piping installation errors, it is possible to perform construction on-site by adjusting the length of the short pipe. It also has the effect of making installation work easier.

The length of the short pipe depends on the material, length, and diameter of the pipe to be connected, but it is generally desirable to have a length of 300 to 500 mm, and it is desirable that the pipe and the short pipe be made of the same material.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a cross-section of the upper half for explaining one embodiment of the method of the present invention, and FIG. 2 is a cross-sectional view showing the welding process by the method shown in FIG. 1.2...Piping 6...-Short pipe 4...Inlay part 5...Convex part 6...Welding part (7317) Attorney Kensuke Chika (and 1 other person)

Claims (1)

[Claims] 15. A convex part and a spigot part are formed on the outer circumferential surface of a short pipe interposed between one pipe and the other pipe or at least one of the pipes, and both the pipes and the short pipe are connected to the spigot part. A method for welding pipes, characterized in that after bringing them into close contact, the convex portion is melted with a torch of a welding machine to fuse and connect both the pipes and the short pipe. 2. The method for welding pipes according to claim 1, wherein one pipe, the hold pipe, and the other pipe are each made of the same material, and a convex portion is formed on the upper surface of at least one of each pipe. .