MULTI-ELECTRODE ELECTROGAS ARC WELDING METHOD FOR THICK STEEL PLATES AND MULTI-ELECTRODE ELECTROGAS ARC CIRCUMFERENTIAL WELDING METHOD FOR STEEL PIPES

摘要

Provided are a multi-electrode electrogas arc welding method for thick steel plates and a circumferential welding method for steel pipes that can establish both welding efficiency improvements and weld defect reduction when butt welding thick steel plates with a plate thickness of 40 - 300 mm or steel pipes to each other vertically. In the multi-electrode electrogas arc welding method, the ends of thick steel plates to be welded are disposed facing each other and a groove is formed therebetween, the root spacing (RO) and root surfaces (RF) at the groove satisfy a predetermined relationship, electrogas arc welding electrodes are disposed at each of both surface sides of the groove, welding is carried out simultaneously from the lower side to the upper side in the vertical direction, and the electrogas arc welding electrodes move in synchrony with the molten surface level of molten welding metal produced within the beveled gap.