SU1542727A1 - Method of exciting three-phase arc in automatic nonconsumable electrode gas-shielded welding - Google Patents

Abstract

The invention relates to welding, mainly to methods for initiating a three-phase arc during automatic welding with non-consumable electrodes in a protective gas environment. The purpose of the invention is to increase the reliability and stability of the arc excitation due to uniform heating of the working surfaces of the ends of the electrodes. The method involves the use of an additional electrode 4 in the form of a roller mounted at the edge of the welded part 5 and electrically connected with it. Arc excitation occurs when moving the torch 3 at a speed V _binding welding direction in the part 5. The electrodes 1 and 2, the burner 3 are closed alternately with the auxiliary electrode 4. Additional electrode 4 due to mechanical contact with the main electrodes 1 and 2 are rotated in the direction of movement of the burner 3. Arcs 6 and 7 alternate between electrodes 1 and 2 and part 5 and arc 8 between electrodes 1 and 2. The method ensures stable and reliable initiation of the arc during automatic welding. 3 il.

Description

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The invention relates to welding, mainly to methods of initiating a three-phase arc during automatic welding with non-consumable electrodes in a protective gas environment, and can be used in any industry of the national authority when conducting automatic welding in a protective gas environment.

The purpose of the invention is to increase the reliability and stability of the arc excitation due to uniform heating of the working surfaces of the ends of the electrodes.

FIG. 1 shows the stage of closing the burner electrodes with an additional electrode; in fig. 2 — the stage of arcing between one of the torch electrodes and the auxiliary electrode; in fig. 3 - the stage of occurrence of all arcs with transfer of one arc from an additional electrode to the part being welded.

The method is implemented as follows.

The main electrodes 1 and 2, fixed in the burner 3, move with a welding speed Vce in the direction of the weld joint and close with an additional electrode 4 installed at the edge of the welded part 5 and having an electrical connection with the part (Fig. 1). Upon further movement of the burner 3, the contact between the electrode 1 and the additional electrode 4 (Fig. 2) breaks down with the appearance of the arc 6. Then the arc 6 is transferred from the additional electrode 4 to the part 5, the contact between the second electrode 2 and additional 4 and the occurrence of arc 7 between them. At the same time there is an arc 8 between the main electrodes 1 and 2 (Fig. 3).

Example. A three-phase arc was excited during automatic welding in argon. Tungsten rods with a diameter of 8 mm were used as electrodes of the welding torch.

figl

The new electrode was made of graphite in the form of a wheel with a diameter of 50 mm and a width of 20 mm, which can be rotated around its own horizontal axis and straight-line up and down.

relative to the vertical axis. Moreover, as the torch electrodes move along it, the additional electrode is constantly raised with the help of a spring to the latter. An additional electrode was installed at

0 edges of the welded product. The speed of movement of the electrodes is 75 m / h, the current in the electrodes is 150 A, the current in the part is 260 A, the distance between the ends of the electrodes and the product is 8 mm, the flow rate of argon is 15 liters / min.

. During a series of experiments, 100% excitation of the arc was observed.

Using the proposed method provides a stable and reliable excitation of the arc during automatic welding, which simplifies the automation of the developed

0 processes and burner operation.

Claims (1)

Invention Formula 25 The method of initiating a three-phase arc in automatic welding with non-consumable electrodes in a protective gas environment, in which the excitation of the arc is carried out when the power source is turned on by closing and then opening the main electrodes From the burner with an additional non-consumable electrode electrically associated with the product, characterized in that, in order to increase the reliability and stability of the arc due to uniform heating of the working surfaces of the electrodes of the genus, the additional electrode is made in the form of a roller, installed at the beginning of the welded joint rotatably and, before closing, the main electrodes are moved with a welding speed 2