JPS5886976A - Arc starting method in arc welding - Google Patents

Abstract

PURPOSE:To facilitate arc starting by bringing a part of a torch into contact with a base metal, tilting the torch with the contact part as a flucrum and attaching and detaching an electrode to and from the base metal. CONSTITUTION:A point A which is a part of a torch is brought into contact with a base metal 3, and with the part A as a fulcrum, the torch, that is, a nozzle part 1 is filted to bring an electrode 2 into contact with the metal 3. In this state, short circuiting current is run and while the part A is held in contact with the metal 3, the short circuiting between the electrode 2 and the metal 3 is opened with the part A as a fulcrum, and an arc 4 is fired. The more preferable embodiment of this arc starting method is an inert gas tungsten arc (TIG) welding method. It is equally well to provide a build-up part at the preceding end edge of the nozzle or to provide at annular projection over the entire circumference thereof and to bring the electrode into contact with the base metal by means of such part of projection.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method of arc welding, particularly TIG welding using a non-consumable electrode, in which the electrode is brought into instantaneous contact with the base metal to ignite the arc, that is, the touch start method. In some 3° TIG welding, a high-frequency arc starter is often used, which generates a high-frequency wave tube only when an arc is generated, starts the arc without bringing the electrode into contact with the base metal, and does not apply high-frequency waves during welding. however,
There are large fish whose high frequencies cause radio interference. Therefore, a starting method in which the electrode and the base metal are brought into instantaneous contact at the start of welding to ignite the arc is also widely used. The principle of this method is shown in FIG. In the figure, 1 is a nozzle, 2 is an electrode, 3 is a base material, and 4 is an arc.

When welding starts, electrode 2 and base material 3 are instantly connected as shown in (a).
Then, the torch is pulled up as shown in FIG. 3(b) to open the short circuit and ignite the arc 4 between the electrode 2 and the base material 3. When using this method, the electrode may be heated and welded to the base metal when the current during a short circuit is large or when arc starting is repeated many times during tack welding. In such a state, a large force is required to pull up the torch, and when the short circuit is released, the torch is pulled up too much, making it difficult to maintain a constant small distance between the electrode and the base metal, which can cause arc breakage. is often the case. Also, if the base material is lightweight and the base material clamp is weak,
The base material may also be pulled up at the same time.

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a method for simply and reliably touch-starting arc welding.

The arc start method in arc welding according to the present invention, in which an electrode and a base material are brought into instantaneous contact to ignite an arc, involves bringing a portion of the torch into contact with the base material, and tilting the torch using the blade contact portion as a fulcrum.

A method characterized by bringing an electrode into contact with a base material and separating it from the base material.

In a preferred embodiment of the arc start method according to the invention, the arc welding is inner gas tungsten arc (TIG) welding.

More preferred embodiments of the arc start method according to the present invention include the following embodiments.

(1) The contact area between the )-chi and the base metal is at the tip edge of the nozzle.

(2) The contact area of the nozzle tip edge with the base material is built-up.

(8) The contact portion between the torch and the base material is a ring-shaped projection provided over the entire tip edge of the nozzle.

(4) The contact part between the torch and the base material is provided at the tip edge of the nozzle, and is diagonally toward the base material on the side of the 9-part 7-tuned piece.
Or, at the tip of the 7-tsunge that protrudes laterally and refracts toward the base material, T.

Ru.

(5) The contact portion between the torch and the base material is a row 2 portion provided at the tip of one or two rods protruding from the torch body or handle toward the base material surface.

The method of the present invention will be explained based on FIG. 2 which shows the principle. The same parts as in FIG. 1 are designated by the same reference numerals.

In this method, first, a part of the torch, point A, is brought into contact with the base material, and the torch, and therefore the nozzle part 1, is moved as a fulcrum at the contact part At, and the electrode 2 is Bring it into contact with the base material 3.

In this state, a short circuit current is applied, and while the contact part A is kept in contact with the base metal 3, the short circuit between the electrode 2 and the base metal 3 is released using the contact part A as a fulcrum, and the arc 4 is ignited as shown in the diagram. do.

In the method of the present invention, various embodiments can be mentioned as a method for forming the contact portion A with the part of the base material of the torch. In the example shown in FIG. 2, the contact portion A is the tip edge of the nozzle 1.

FIG. 3 shows a nozzle 1 with a fleshy part 5 provided on the tip edge thereof, and the built-up part 5 is brought into contact with the base material.

FIG. 4 shows a nozzle 1 in which a ring-shaped protrusion 6 is provided around the entire circumference of the tip edge, and the ring-shaped protrusion 6 is connected to the base material.

FIG. 5 shows an example in which flange pieces 7A and 7B7C are attached to the tip edge of the nozzle 1, the tips of the flanges coming into contact with the base material. 7 Tsunji pieces? In Al7B and Al7C, each of the 7 langes protrudes diagonally toward the base material and laterally, then bends and protrudes toward the base material. The base material 3 is traced by a roller 9 at the tip of one (or two) rods 8 protruding toward the material surface, and the rollers 9 of the rods 8 are used as a fulcrum. be.

A member for contacting the base material of the torch in each example (5
, 6, 7, 8, 9) facilitate contact and separation operations between the extremely small electrode 2 and the base material 3, and also serve to reinforce and maintain the tip edge of the nozzle 1.

The welding voltage and shielding gas may be applied before or after the electrode contacts the base material.When bringing the electrode into contact with the base material, it is necessary to do so using the part of the torch that makes contact with the base material as the fulcrum. However, it is better to use the mosquito contact area as a fulcrum in order to avoid collisions between the electrode and the base material, and to be aware of the distance between the electrode and the base material. In particular, when welding voltage is applied before contacting the electrodes, it is better to use the contact portion as a fulcrum during contact in order to shorten the contact time. Furthermore, when the method of the present invention was used in a device that performs output control using an IA with a cycle of the commercial power frequency, it was particularly easy to start.

Since the method of the present invention is configured and implemented as described above, the following effects can be achieved.

Arc starting is now easy even without a medium/high frequency generator.

(N) When igniting an arc with the electrode separated from the base metal, part of the torch remains in contact and rotates using this as a fulcrum, so the distance between the electrode and the base metal is kept small and constant. Easy to keep and summer nine.

(till) Even under conditions where the base material and electrode are likely to weld, the base material is not pulled up at the same time as the electrode because part of the torch holds down the base material.

4%J Since the torch is tilted, it is easy to see the arc start point.

[Brief explanation of drawings]

Figures 1 (a) * (b) are principle diagrams for explaining the conventional arc start method, and Figures 2 (1) and (b) are principle diagrams for explaining the arc start method of the present invention. Figures 3 to 6 show embodiments of the nozzle ν or torch for carrying out the method of the present invention, and Figure 3 is a longitudinal cross-sectional view (Figure a) of one embodiment.
and a bottom view, FIG. 4 is a vertical sectional view of another embodiment, and FIG.
a) , (b) , (((ri) is a side view of an embodiment in which flange pieces of different shapes are provided, and FIG. 6 is a side view of a different embodiment in which a rod with a roller is provided.1. ... Nozzle, 2... Electrode, 3... Base material, 4... Arc, 5... Overlay part, 6...
・Ring-shaped projection, 7A, 7B, 7C...]2
8...rod, 9...roller, A
...Contact part. Representative Patent Attorney Susuki 1) Li Kushi/j1\ Nell Fodder 2 Questions (α) (b) 3'th, 4121st (a-) tl+ (L) (/A) (C
) Procedural amendment (G style) Table of cases Patent application No. 72 Tag 3 Tag 3 The name of the invention IIFI and υJIll Patent Applicant II Location 2-6-2 Otemachi, Chiyoda-ku, Tokyo Name Representative of Hitachi Seiko Co., Ltd. Residence Address 11F, Marunouchi-F, Marunouchi, Chiyohi-ku, Tokyo 11F 'l:+ili infliJJr
䆆I, I27o-211I<Oshiro a+=41

Claims (1)

[Claims] (1) In the arc start method in arc welding, in which an electrode and a base material are brought into instantaneous contact to ignite an arc, a portion of the torch is brought into contact with the base material, and the contact portion is used as a fulcrum. An arc start method in arc melting* that is characterized by tilting the torch to bring the electrode into contact with and away from the base material. (2) The arc start method in arc S* according to claim 1, wherein the arc welding is inner gas tungsten arc (TIG) welding. (3) The arc start method for arc welding according to claim 2, wherein the contact portion between the torch and the base metal is at the tip edge of the nozzle. (4) The arc start method in arc welding according to claim 3, wherein the contact portion of the tip edge of the nozzle with the base material is an internal bulge. (j) The arc start method for arc welding according to claim 3, wherein the contact portion with the base metal is a ring-shaped projection provided over the entire circumference of the tip edge of the nozzle. (6) The contact portion with the base material is provided on the tip edge of the nozzle, and is protruded diagonally or laterally toward the base material and bent to the side of the 9-part 7-way piece. 64. The arc start method in arc welding according to claim 3 at the tip of the seven flange protruding toward the material. (7) The contact portion between the torch and the base material is made to protrude from a part of the torch body or the hand toward the base material surface.
The arc start method in arc welding according to claim 2, wherein a nine roller portion is provided at the tip of a book or two rods.