JPS61206568A - Tig arc welding torch - Google Patents

Abstract

PURPOSE:To perform a stabilized welding with free adjustment of the distance between an electrode and wire tip and with observing a molten pool by sliding in the up and down directions the hot wire guide nozzle inclined in the direction of tungsten electrode. CONSTITUTION:A hot wire guide 12 is fastened to a wire guide holding jig 14 and is slided in vertical direction along a gas nozzle 2 and contact tube 11 by the thread 15 worked on the wire guide nozzle 10 and adjusting screw 16 for vertical movement. The distance between the tip of a hot wire 13 and tungsten electrode 7 can thus be adjusted freely.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a TIG arc welding torch, and particularly to a welding torch for hot wire TIG.

(Prior art) TIG (tungsten inert gas) welding, which performs welding by generating an arc between a non-consumable tungsten electrode and a base metal in an inert gas atmosphere such as argon, is superior to other welding methods. Although the welding efficiency is inferior, the soundness of the welded part is excellent, and it is often used for welding alloy steels such as stainless steel and for welding parts where reliability is required. In TIG welding, unlike so-called consumable electrode welding such as covered arc welding and MAG welding, in which the electrode itself is melted by an arc to form weld metal, additive wire is used to use non-consumable tungsten as the electrode. It is necessary to feed the metal near the arc and melt it to form molten metal. The additive wire is fed either by directly feeding a wire with a diameter of 2.4 mm, or by automatically feeding a wire with a diameter of about 1.0 nm wound on a reel with a roller via a wire guide fixed to a torch. There are methods, but the automatic feeding method is the most popular method to improve welding efficiency. In the welding of thin plates, various methods have already been put into practical use depending on the application. FIG. 3 shows an example of a TUG arc welding torch that integrates a conventional additive wire automatic feeding mechanism and a tungsten electrode holding mechanism. The torch fixing member 1 is provided with a shielding gas nozzle 2 and a tungsten electrode 7, and is also provided with a contact tube 1.1 integrally fixed to the torch fixing member 1 and a dosing wire 25 passing therethrough. In the figure, 8 is a cooling water pipe, 18 is a screw for adjusting the angle of the additive wire, 19 is a gas pipe, and 20 is a screw for adjusting the front and back of the additive wire.

However, with conventional welding torches, the width of the shield gas nozzle 2 alone is as large as 20 m or more, and when applying it to butt welding of thick plates, it is necessary to insert the torch into the groove. There is a problem in that the groove width has to be significantly increased to 20 mm, which significantly reduces welding efficiency.

In order to solve these problems, it is necessary not only to make the welding torch thinner so that it can be inserted into narrow grooves, but also to take measures to make it easier to observe the arc and molten pool inside the groove. It is. In addition, in order to improve the welding rate when welding thick plates, a hot wire TIG welding method is used in which current is passed through the additive wire to heat it, and the hot wire guide mechanism and tungsten electrode holding mechanism are electrically insulated. Measures to do so are also required. In hot wire TIG welding, the hot wire is usually placed behind the arc, its tip inserted into the molten pool, and energized between it and the base metal.

However, if the tip of the real wire moves away from the arc and comes out of the molten pool, the current flowing through the wire decreases and the wire is not effectively heated and melted, making it impossible to form a normal bead. Furthermore, if the tip of the hot wire gets too close to the arc, the arc becomes unstable, making it difficult to perform good welding. That is, in hot wire TIG welding, the distance between the hot wire tip and the arc, that is, the tungsten electrode, is a controlling factor that has a significant effect on the welding result. Measures to control this are also necessary.

To solve these problems, a welding torch was devised for welding thick plates with a narrow gap of 10 mm or less.
(Patent Application No. 1771213/1982).

FIG. 4 is a side view of a conventional narrow gap automatic TIG welding torch, and FIG. 4A is a front view of the same as viewed from A. In the figure, a torch fixing member 1 is inserted into a shield gas nozzle 2.
3 is arranged, and a tungsten electrode holding plate 4 is fixed to the lower part of the gas nozzle 3. On the other hand, the gas nozzle 2 has a contact tube 11 through which a hot wire passes in the length direction.
is fixed. Further, at the lower end of the contact tube 11, a ceramic hot wire guide 12 is fixed between the electrode holding plate 4 and the gas nozzle 2. The tungsten electrode 7 is inserted into the electrode hole 5 provided in the electrode holding plate 4, and is tightly attached to the electrode holding plate 4 by a pressing spring 22 and a protrusion 23, which are also placed in the center of the electrode holding plate 4. The tungsten electrode 7 is attached to the torch fixing member l.
The electrode adjustment screw 21 is threaded into the electrode adjustment screw 21 and held therein. With such a structure, the tungsten electrode 7 can be moved in the vertical direction using the adjustment screw 21. The hot wire 13 includes a wire guide nozzle 10, a contact tube 11 and a wire guide 12.
It is bent and fed to the tungsten electrode 7 side via the tungsten electrode 7 side. The angle θ is 50 to 70 degrees. For this reason, the tungsten electrode 7, the location of the arc and the hot wire 1
The distance from the tip of the tungsten electrode 7 can be adjusted by moving the tungsten electrode 7 in the vertical direction. Note that the holding mechanism for the tungsten electrode 7 and the guiding mechanism for the hot wire 13 are electrically isolated by an insulator 9 such as Bakelite and a wire guide 12 made of ceramics. moreover,
As mentioned above, since the feeding angle θ of the hot wire is large, it is easy to observe the molten pool from behind the welding.

On the other hand, in automatic TIG welding, a method is adopted in which the position of the welding torch is controlled so as to keep the arc length approximately constant so that stable welding can be performed. That is, an arc voltage that uniquely determines the arc length is detected, and a servo motor is used to move the welding torch in the vertical direction. Therefore, when the arc length is varied by moving the tungsten electrode 7 up and down, the arc voltage also changes rapidly.
It has been found that errors may occur in the arc length control mechanism. In addition, even when arc length constant control is not performed, the length of the molten metal varies slightly depending on influencing factors such as current, voltage, and groove width. wire 1
It may be difficult to control the distance of the tip of 3.

(Problems to be Solved by the Invention) The purpose of the present invention is to freely adjust the distance between the tungsten electrode and the tip of the hot wire even in a deep groove, and to perform stable welding while observing the molten area. An object of the present invention is to provide a thin TIG arc welding torch that can perform

(Means for Solving the Problems) In short, the present invention provides a torch in which a tungsten electrode holding mechanism and a hot wire guide mechanism are integrated, in which a hot wire guide nozzle tilted toward the tungsten electrode is slid vertically. The distance between the tungsten electrode and the tip of the hot wire can be adjusted by moving the tungsten electrode. That is, the present invention provides a TIG arc welding torch that integrally incorporates a holding mechanism for a tungsten electrode that forms an arc and a guide mechanism for a hot wire. In order to adjust the distance between the tip of the hot wire in contact with the central axis of the tungsten electrode, the wire guide is characterized by having a mechanism for moving the wire guide up and down during welding.

In the present invention, the wire guide that bends and feeds the hot wire coming out of the contact tube toward the tungsten electrode is made of ceramic, and the wire guide is connected along the hot wire guide mechanism fixed to the welding torch such as the contact tube. It is preferable to be able to move up and down.

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

1 and 1A are a side view and a front view showing one embodiment of the TIG arc welding torch of the present invention. In FIG.
A wire guide nozzle 10 and a hot wire guide 12 are fixed via a cooling pipe 8 and an insulating member 9. The part that fixes the tungsten electrode 7 holding mechanism is:
It consists of a gas nozzle 3, a cooling water pipe 8, and an electrode holding plate 4 fixed to the lower part thereof, and the part to which the hot wire guide mechanism is fixed consists of the gas nozzle 2 and a contact tube 11. These parts are electrically isolated by an insulating member 9 made of Bakelite or the like. The electrode holding plate 4 is provided with an electrode hole 5 into which a tungsten electrode 7 is inserted, and is fixed to the electrode holding plate 4 with an electrode fixing screw 6.

This tungsten electrode 7 is connected to a TrG arc power source (not shown) via a torch fixing member 1, a gas nozzle 3, and a cooling water pipe 8. The contact tube 11 into which the real wire 13 is fed is fixed to the gas nozzle 2 and further fixed to the electrode holding plate 4 by an insulating member 24 made of ceramics. Contact tube 11
is connected to a hot wire power source (not shown), and the hot wire 13 is energized through this contact tube 11. The hot wire guide mechanism is electrically isolated from the tungsten electrode holding mechanism by an insulating member 9.24. The gas nozzle 2 or the gas nozzle 2 and the contact tube 11 are made of a thin ceramic cylinder 1.
2, and a hot wire 13 is inserted and supported below it.
An inclined hole is provided so that the tungsten can be fed to the tungsten electrode 7 side. The hot wire guide 12
It has the cross-sectional shape shown in the figure, and is fastened to the wire guide holding jig 14, and the wire guide 1
2 can be slid vertically along the gas nozzle 2 and contact tube 11.

Since the TrG arc welding torch according to the present invention has the above configuration, the wire guide 12 can be easily moved up and down using the adjustment screw 16, and the distance between the tip of the hot wire 13 and the tungsten electrode 7 can be adjusted as desired. can be adjusted to In addition, the arc length is controlled by detecting the arc voltage (1) as described above, and the entire welding torch is controlled by the servomotor, but in the present invention, the arc length is controlled completely independently of the vertical movement of the welding torch. The addition position of the wire 13 to the molten pool can be adjusted.

Furthermore, in hot wire TIG welding, unless the protruding length of the wire is kept constant, the heating of the wire will not be constant; however, according to the welding torch of the present invention, the entire hot wire guide mechanism can be moved up and down. Unlike in the case where the contact tube 11 is moved, the distance from the lower end of the contact tube 11 to the molten pool does not change, so stable welding can be performed. Furthermore, since the wire guide 12 made of high melting point ceramic is present between the contact tube 11 and the molten pool,
The contact tube hole will no longer be clogged with spatter or the like.

We made a prototype welding torch with the inclination angle θ of the hole provided in the wire guide 12 of 70 degrees, and measured the change in the distance between the tungsten electrode 7 and the tip of the hot wire 13 by moving the wire guide up and down. I was able to freely adjust it up to 7fl. In actual welding, the distance is 3fl
It was found that 5N is appropriate and can be put into practical use. In addition, the tungsten electrode 7 will be somewhat worn out during welding, but if you take into account the wear bone and make it stick out long from the electrode holding plate 4 before welding, the tip of the real wire 13 can be adjusted during welding, so you can cut the arc. There is no need for readjustment, and welding can be performed continuously for a long time.

Although narrow gap hot wire TIG welding has been described above, the present invention is not limited to narrow gap welding, and can have similar effects even when applied to a normal TIG arc welding torch.

(Effects of the Invention) According to the present invention, a thin welding torch that can be sufficiently inserted into a narrow gap is provided.
The body of a steel pressure vessel with a diameter of 500 m-1i thick
Narrow gap welding of Tsuru stainless steel piping using hot wire TIG is also possible.

Therefore, the scope of application of the narrow gap e7) wire TIG welding method, which allows high efficiency and high quality welds to be obtained, has been expanded, and its industrial value is great.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of a TIG arc welding torch according to the present invention, FIG. 1A is a front view as viewed from A in FIG. 1, and FIGS. 2 and 2A are shown in FIG. 1. 3 is a structural diagram of a conventional welding torch for thin plates, and FIG.
FIG. 4A, a side view of a conventional welding torch for narrow grooves, is a front view in the direction of A in FIG. 4. DESCRIPTION OF SYMBOLS 1... Torch fixing member, 2.3... Shield gas nozzle, 4... Electrode holding plate, 5... Electrode hole, 6...
・Electrode fixing screw, 7...Tungsten electrode, 8...
Cooling water pipe, 9... Insulating member, 10... Wire guide nozzle, 11... Contact tube, 12...
Hot wire guide, 13...Hot wire, 14.
...Hot wire guide holding member, 15...Upper and lower adjustment screw. Agent Patent Attorney Takenaga Kawakita Figure 1 Figure 2 Figure 28 Figure 3

Claims (2)

[Claims] (1) In a TIG arc welding torch that integrates a tungsten electrode holding mechanism that forms an arc and a hot wire guide mechanism, there is a wire guide that can bend and feed the hot wire to the tungsten electrode side, and a wire guide that can bend and feed the hot wire to the tungsten electrode side. TI characterized by having a mechanism for moving the wire guide up and down during welding in order to adjust the distance between the tip of the hot wire and the central axis of the tungsten electrode.
G arc welding torch. (2) In claim 1, the wire guide that bends and feeds the hot wire coming out of the contact tube toward the tungsten electrode is made of ceramic, and the wire guide is fixed to a welding torch such as the contact tube. A TIG arc welding torch characterized by being able to move up and down along a hot wire guide mechanism.