JPH04751B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a TIG arc welding torch, and particularly to a welding torch suitable for magnetically oscillating an arc within a narrow gap.

In TIG welding, when it is desired to widen the bead width without increasing the arc current too much, it is usually done to mechanically occlude the torch, or to apply a magnetic field to the arc generating area from the outside to magnetically occlude the arc. .

On the other hand, when performing narrow gap TIG welding, if the groove width exceeds approximately 7 mm, it becomes difficult to stably melt both groove side walls while forming an arc at the center of the groove. When attempting to weld one layer in one pass, it is necessary to oscillate the arc by some method.

However, for example, a narrow gap configured with a thickness of about 5 mm
Even if a TIG torch is mechanically oscillated by about 1mm plus or minus in a deep narrow gap with a width of 9mm, the arc will move while pointing straight down, making it difficult to control. is not useful for melting the groove corners, which is a problem in causing welding defects.

Therefore, it is better to magnetically oscillate the arc while holding the tungsten electrode (hereinafter referred to as the W electrode) at the center of the groove, so that the arc faces the groove corner more accurately and can perform good melting. It is expected that this will happen.

Figures 1 and 2 show a conventional narrow gap TIG welding torch. The W electrode 1, which is a non-consumable electrode, is connected to the electrode holding plate 2.
It is held tightly by the action of a spring 3, and is cooled by a cooling water pipe 4 having a reciprocating path inside. An arc is formed at the tip of the W electrode, but
In order to accurately perform gas shielding in a deep narrow groove, in addition to providing a shielding gas (not shown) on the surface of the base material, a shielding gas pipe 5, which is usually made of copper, is installed.
6, gas flows out into the vicinity of the arc to shield it. The addition wire 7 is guided by a contact tube 8 whose tip is bent toward the W electrode 1 side and fed into the molten pool, and the addition position is determined by moving the contact tube 8 up and down with an adjustment screw 9.

The gas pipes 5, 6 and the cooling water pipe 4 are fixed to the upper part of the torch 10 by a torch fixing member 11, and are integrated by brazing to the electrode holding plate 2 at the tip of the torch. The additive wire 7 and the contact tube 8 are electrically insulated from the torch body by a guide 12 made of ceramics and a slide base 13 made of Bakelite.

Note that the cooling water and gas enter and exit from the side of the torch 10. Conventional narrow-gap TIG welding torches generally have the above-mentioned structure, so additional magnetic poles are provided in front and behind the torch in the welding direction, that is, in close proximity to the shield gas pipes 5 and 6, to form a magnetic field that crosses the arc. Even if an attempt was made to oscillate the arc, the tips of the two magnetic poles were spatially too far apart, and as a result, the magnetic field applied to the arc was too weak, making it virtually difficult to oscillate the arc magnetically.

The purpose of the present invention is to eliminate the drawbacks of the prior art described above, and to provide a TIG torch that can oscillate an arc in the groove width direction within a narrow gap without essentially changing the structure of the compact narrow gap TIG torch. It is on offer.

In short, this invention provides a TIG arc welding device that performs welding by alternately deflecting a magnetic field and swinging the arc, which includes a torch fixing member through which an electromagnetic coil is inserted, a shield gas pipe, a cooling water pipe through which cooling water flows in and out,
The respective ends of the shield gas pipes are connected in order and allowed to hang down, and the electrode holding plate connected to the lower end of the cooling water pipe is held between the ends of the shield gas pipes and brought together to form a torch body. A contact tube for additive wire having a diameter smaller than the width of the narrow groove is electrically insulated and connected to the torch body,
This is a narrow-gap TIG welding torch characterized by having a hanging part formed in the form of a plate as a whole, which is thinner than the width of the narrow-gap.

Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 3 and 4, shield gas pipes 5 and 6 are arranged front and rear with respect to the welding progress direction, centering on the cooling water pipe 4, and a torch fixing member 1.
1 is made of a material with high magnetic permeability, such as electromagnetic soft iron or mild steel. As a result, a substantially horse-shaped magnetic path is formed so as to sandwich the W electrode 1 at its tips. 14
is a coil wound around the torch fixing member 11, and by passing a tributary excitation current to this coil 14, a magnetic field is formed in a direction that crosses the arc forming part at the tip of the torch, thereby creating an arc-shaped bevel. It will now oscillate in the width direction.

The inventors formed a groove with a width of 10 mm in the SUS304 series stainless steel base material, and using the torch of the present invention with a shield gas pipe 5 of 100 mm in length, an arc was generated under the condition of a supplied power of 240 A. When magnetically oxidized, it was possible to stably melt both side walls of the groove.

However, in the case of a carbon steel base material with similar grooves, the arc could hardly be oscillated. In other words, when the base material is a ferromagnetic material such as carbon steel, the magnetic field acting on the arc is substantially weakened, and magnetic oscillation is difficult, including this invention. It is extremely effective in the case of paramagnetic materials.

This invention is carried out using a TIG arc, and it goes without saying that the additive wire may be a normal cold wire or a hot wire heated by passing an electric current through the wire. In addition, the TIG arc is a pulsed arc, and the wire is not energized during the peak current period, but the wire is energized during the base current period, thereby virtually eliminating the magnetic blowing phenomenon that is inherent in the hot wire method. When applied to the switching TIG method,
This invention can exhibit greater effects.

Since this invention has the above configuration, the following effects are produced by implementing this invention.

That is, although the structure and size of the torch inside the groove are almost the same as before, it has become possible to magnetically oscillate the arc within the narrow groove. For this reason, conventional narrow gap welding by TIG using the one-layer, one-pass method required a groove width of up to 8 mm, but with the torch of the present invention, even a groove width of 12 mm can be applied to both side walls of the groove. It is now possible to melt sufficiently and perform stable welding. This means that the tolerance range for groove width fluctuations during narrow gap welding has been expanded, and the measures required to maintain groove precision and prevent deformation during welding are greatly reduced. This also greatly helps in preventing the formation of welding defects due to poor fusion at the leading corner.

[Brief explanation of drawings]

Fig. 1 is a front view of a conventional narrow gap TIG welding torch, Fig. 2 is a side view of the same, Fig. 3 is a front view of a narrow gap TIG welding torch according to the present invention, and Fig. 4 is a side view of the same. be. 1... Tungsten electrode, 5, 6... Shield gas pipe, 10... Torch.

Claims (1)

[Claims] 1 In a TIG arc welding device that performs welding by alternately deflecting a magnetic field and swinging the arc, the shield gas pipe, the cooling water pipe through which cooling water flows in and out, and the shield gas pipe are connected to the torch fixing member through which the electromagnetic coil is inserted. The ends are connected in order and allowed to hang down, and the electrode holding plate connected to the lower end of the cooling water pipe is held between the ends of the shield gas pipe and brought together to form a torch body, and this torch body has a narrow groove width dimension. A narrow gap TIG characterized in that a contact tube for additive wire with a smaller diameter is electrically insulated and connected to the torch body, and the hanging portion is formed into a plate shape as a whole with a thickness thinner than the width of the narrow groove. welding torch.