Welding torch for first electrode for multi-electrode submerged arc welding and welding method using same

Abstract

The present invention provides a welding technique for multi-electrode submerged arc welding that is stable even if a small-diameter wire is used with a first electrode, in particular if welding is being carried out under welding conditions where the wire feed speed increases or if there is considerable kinked winding, even after correction, with a flux cored wire. A welding torch for a first electrode for multi-electrode submerged arc welding and a method for multi-electrode submerged arc welding using the same are characterized by comprising a means for insulating, from an electrode wire, a tubular electric conductor that is arranged between a power supply chip and a connecting part of a power supply cable.

Description

technical field [0001] The present invention relates to a first electrode torch for multiple-electrode submerged arc welding of thick steel plates suitable for applications such as seam welding of large-diameter steel pipes. ) and the multi-electrode submerged arc welding method using it. Background technique [0002] Submerged arc welding has the following characteristics: the quality of the welded part is good; ) under welding. Therefore, multi-electrode submerged arc welding with two or more electrodes is generally used for welding thick steel plates whose welding lines are straight and long, so that high-quality and efficient welding can be performed. [0003] In order to improve the welding efficiency of thick steel plates, it is necessary to increase the penetration depth and deposition rate. The penetration depth is defined by the distance from the steel plate surface to the lower end of the weld metal. In submerged arc welding, since a large welding current can be...

AI Technical Summary

Problems solved by technology

However, there is a problem in that welding efficiency (welding efficiency) and defect suppression (prevention of slag inclusion, etc.) are overemphasized compared with the advantages of large current and large heat input welding, resulting in excessive welding heat input, In turn, the toughness of the weld, especially the heat-affected zone (Heat Affected Zone: HAZ) deteriorates

However, special insulating jigs and insulators are required, and there is a problem of poor workability when setting the electrode angle of multiple electrodes and replacing the power supply tip.

In addition, since the feeding point is located 50 mm to 100 mm above the tip of the feeding tip and close to the welded part, the aging resistance of the feeding cable may become a problem due to large radiant heat.

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