JPH0289577A - Method for repair welding of defective piping - Google Patents

Abstract

PURPOSE:To execute repair welding by generating an arc, while suppressing bleeding of an internal fluid by using a hollow electrode for a W electrode held by a TIG welding torch, feeding a welding wire from an inner cavity of the hollow electrode, and simultaneously allowing shielding gas to flow. CONSTITUTION:At the time of repairing a piping in which a fluid is contained, a hollow W electrode 9 and a welding wire 10 protruded from its tip are allowed to confront a defective part 13, and an arc 15 is generated between both of them. Subsequently, a temperature of water or vapor 14 in a piping 12 rises and the water or vapor is going to bleed out through the defective part, but shielding gas is allowed to flow intermittently from an inner cavity of the hollow W electrode 9, and the water or vapor is pushed in the direction as indicated with an arrow into the piping 12. The arc 15 and a molten pool which is formed are stabilized the welding wire 10 is supplied automatically thereto and a sound weld bead 16 is formed. In such a way, while suppressing bleeding an internal fluid from the defective part of the piping, sound repair welding can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a welding method for repairing defective parts of pipes, which is applied to repairing defective parts of pipes containing liquid or gas, particularly defective joints.

[Conventional technology]

Conventionally, when a defect occurs in a pipe joint, TIG is usually used.
Repair welding is performed using a welding method, and the welding mode is explained with reference to a vertical cross-sectional view in FIG. 2 is formed, an insulator 3 is placed around the welding torch body 1, a collet chuck 4 and a collet body 5 are housed in the lumen of the welding torch body 1, and a shielding gas is fed into the lumen of the welding torch body 1. A collet 8 is inserted into the inner cavity of the collet body 5.
A solid tungsten electrode 9' is inserted and held in the axis of the TIG welding torch, and the tip of the tungsten electrode 9'' of such a TIG welding torch is made to face the defective part 13, and the welding wire 10 is supplied from the side to remove the tungsten. Repair is performed by generating an arc 15 between the tip of the electrode 9 and the defective part 13 to form a weld bead 16 on the surface of the defective part 13.

However, in such a repair welding method, if water or steam 14 remains in the pipe 12, it oozes out from the defective part 13 during repair welding, making it difficult to properly perform repair welding. It is difficult to do so.

[Problem to be solved by the invention]

The present invention was proposed in view of these circumstances, and
It is an object of the present invention to provide a welding method for repairing a defective part of a pipe by generating an arc while suppressing seepage of internal fluid from the defective part of the pipe and performing sound repair welding.

[Means to solve the problem]

To this end, the present invention uses a hollow electrode as a tungsten electrode held in a TIG welding torch to repair and weld defective parts of piping containing fluid by TIG welding, and a welding wire is inserted from the inner cavity of the hollow electrode. It is characterized by supplying gas and flowing shielding gas from the same inner cavity.

[Effect]

With the above-mentioned configuration, it is possible to obtain a welding method for repairing a defective pipe portion, which can generate an arc while suppressing internal fluid from seeping out from the defective portion of the pipe, and perform sound repair welding.

Embodiment] An embodiment of the welding method for repairing a piping defect according to the present invention will be described with reference to a vertical cross-sectional view in FIG.

In FIG. 1, the pipe 12 has a joint defect 13 and water or steam 14 remains inside. A welding torch for repairing and welding a defective part 13 of such a pipe 12 has a shield cup 2 formed at the tip of a welding torch body 1, an insulator 3 covering the periphery, and a shield cup 2 in the inner cavity of the welding torch body 1. Collet chuck 4 and collet body 5
In addition, a through hole 7 for a shielding gas 6 to be introduced into the inner cavity of the welding torch body 1 is bored in the throat body 5.

A collet 8 whose base is connected to the collet chuck 4 is fitted into the inner cavity of the collet body 5, and a hollow tungsten electrode 9 is inserted and held in the axis of the collet 8. As well as the welding wire 10 being fed, the shielding gas 11 is also fed.

When repairing the defective part 13 of the piping 12 using such a welding torch, the hollow tungsten electrode 9 and the welding wire lO protruding from its tip are attached to the defective part 1.
3 and generate a 7-k 15 between them, the temperature of the water or steam 14 in the pipe 12 rises and the defective part 13
However, when the shielding gas 11 is intermittently flowed from the inner cavity of the hollow tungsten electrode 9, the water or steam 14 that is about to seep out is suppressed in the direction of the arrow inside the pipe 12, and the arc 15 The molten pool thus formed is stabilized, and the welding wire 10 is automatically fed thereto to generate a sound weld bead 16.

According to this method, when repairing a defective joint of the pipe 12 in which water or steam 14 remains by TIG welding, the hollow tungsten electrode 9 is used and the welding wire 10 is fed from the hollow part. By intermittently flowing the shielding gas 11 while suppressing the water or steam 14 that tends to seep out from the joint defective portion 13, sound repair welding can be performed.

〔Effect of the invention〕

In short, according to the present invention, when repairing a defective part of a pipe containing fluid by TIG welding, TIG
A hollow tungsten electrode is used as the tungsten electrode held in the welding pipe, and by feeding the welding wire through the inner cavity of the hollow electrode and flowing shielding gas through the inner cavity, internal fluid oozes out from the defective part of the piping. The present invention is extremely useful industrially because it provides a welding method for repairing defective pipes by generating an arc while suppressing the occurrence of arcs and performing sound repair welding.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the welding method for repairing defective pipe parts according to the present invention. FIG. 2 is a longitudinal sectional view showing a conventional repair welding method. ■... Welding torch body, 2... Shield cup, 3
... Insulator, 4 ... Collet chuck, 5 ... Collet body, 6 ... Shield gas, 7 ... Through hole, 8 ... Collet, 9 ... Hollow tungsten electrode,
10... Welding wire, 11... Shielding gas, 1
2... Piping, 13... Joint defective part, 14... Water or steam, 15... Arc, 16... Welding bead. Agent: Masafumi Tsukamoto, Patent Attorney

Claims (1)

[Claims] When repairing and welding a defective part of a pipe containing fluid using the TIG welding method, a hollow tungsten electrode is used as the tungsten electrode held in the TIG welding torch, and a welding wire is fed from the inner cavity of the hollow electrode. A welding method for repairing piping defects characterized by flowing shielding gas from the inner cavity.