JPS6234676A - Butt welding method for tube - Google Patents

Abstract

PURPOSE:To easily perform a stabilized butt welding with automatic welding without using a brazing filler metal by making a slit work near the tube but end part and by melting the annular part between the butt part and slit. CONSTITUTION:An annular part 5 is formed by working a slit 3 near the butt end 2 of a tube 1' and the tube 1 of an 'Inconel 600(R)' and its automatic welding is performed by the arc of a torch T without adding any filler metal. The generation of easily tracing deposited metal is thus eliminated by the dilution of the mutual components of both rubes 1, 1' and the dilution ratio of the components can be varied as well. Consequently as stable butt welding can be thus performed easily with automatic welding without using filler metal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method for butt welding tubes, and more particularly to a method for butt welding vetineve without supplying filler metal.

[Prior Art 1] Conventionally, when butt welding tubes made of different materials, for example, a ferritic tube 12 and an austenitic tube 11 as shown in FIG. Welding may be performed while adding an austenitic filler metal, or a filler ring 15 as shown in FIG.
11 butts and welding was performed without using filler metal.

In automatic butt welding of tubes, filler metal is often not used, but the effort required to fit up the filler ring between the tubes is complicated, and the ease of installing the filler ring is difficult. and stability was insufficient.

Furthermore, as shown in Fig. 4, when performing internal bore welding in which the tube 11 and tube sheet 13 are butt welded, almost no filler metal is used; If the welds are lopsided, it is difficult to perform sound welding, but if welding is performed by sandwiching a filler ring 15 as shown in FIG. 5 between the abutting portions as in the case of FIG. 3, weldability is good. However, in this case too,
Filler ring and installation are extremely complicated and difficult fit-ups.

[Problem to be Solved by the Invention 1] The present invention solves the problem by combining tubes as described above, or
In view of the difficulty in attaching a filler ring to the butt part in butt welding between a tube and a tube sheet, the present inventor has conducted intensive research and found that there is no need to add filler metal, and there is no need to add filler metal. We have developed a tube butt welding method that provides stable welding quality without the need to insert a filler ring, which requires a complicated process to fit up the butt part of the welded object.

[Means for Solving the Problems] The tube butt welding method according to the present invention is characterized in that in tube butt welding, a slit is formed in the vicinity of the tube butt end, and then the tube butt end and the slit are The purpose is to weld the tubes by melting the ring-shaped part between them.

The tube butt welding method according to the present invention will be explained in detail below.

In the tube butt welding method according to the present invention, the slit may be formed on either the inner or outer surface of the tube,
Alternatively, the slit may be formed on both the inner and outer surfaces of the tube, and the slit may be formed on either one side or both sides of the tube abutting portion.

Further, in the tube butt welding method according to the present invention,
The ring-shaped portion between the butt end of the tube and the slit can be melted using a TIG arc, an electron beam, a laser beam, plasma, or the like.

Next, a tube butt welding method according to the present invention will be explained using an example shown in the drawings.

In Figure 1, when butt welding tubes made of different materials, tube 1' and tube 1 made of Inconel 600, if automatic welding is performed without adding filler metal, the two tubes will crack due to dilution of their mutual components. It becomes a metal that is easy to weld. Therefore, by forming a slit 3 near the abutting end 2 of the Inconel 600 tube 1 and melting the ring-shaped part 5 formed there by a T-f-T arc, the components of the weld metal can be removed as described above. Change the dilution ratio
As a result, a sound weld can be obtained.

Most of the internal-bore welding shown in Fig. 2 is automatic welding without adding filler metal, and the position of the arc end, the misalignment of the butt portion, the size of the gap between the butt portions,
Fine control was required to obtain a sound weld due to the difference in heat mass between the butted tube and the tube sheet flange. Therefore, a slit 3 is formed in the tube 1 near the abutting portion 2 between the tube 1 and the tube sheet 4.
The tube 1 and the tube sheet 4 can be easily welded by melting the ring-shaped portion 5 formed between the slit 3 and the abutting portion 2 by appropriate means.

As explained in Figures 1 and 2, the ring-shaped part between the butt part and the slit made in the tube can be easily melted as a type of filler metal, so stable and sound welding can be achieved. It can be done.

[Effect of the invention 1 As explained above, although the tube butt welding method according to the present invention has the above configuration, it is possible to easily butt weld tubes by automatic welding without using a welder. Moreover, it has the effect that stable and sound welding can be performed.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of a tube butt welding method according to the present invention, and FIGS. 3 to 5 are explanatory diagrams of a conventional tube butt welding method. 1.1'...tube, 2...butting part, 3...slit, 4...tube sheet, 5...ring-shaped part, T...
·torch. 1st figure 2wi 3rd figure 42 5th figure

Claims (1)

[Claims] In tube butt welding, a tube butt welding method is characterized in that the tubes are welded by forming a slit near the butt ends of the tubes, and then melting a ring-shaped part between the tube butt ends and the slits.