SUBMERGED ARC WELDING METHOD WITH MULTIPLE ELECTRODES FOR STEEL MATERIAL

摘要

Provided is a submerged arc welding method with multiple electrodes for a steel material suitable for use in welding for manufacturing a large-diameter steel pipe such as a UOE steel pipe, a spiral steel pipe, or the like the base material thickness of which is between 10 mm and 50 mm. Specifically, when the steel material is submerged arc welded with multiple electrodes of three or more electrodes, a direct-current power source is used for feeding power to a first electrode. The welding by the first electrode is performed at a current density of 250 A/mm2 or higher, preferably a wire diameter of 3.2 mm, and a welding current of 1000 A or higher, and the welding by a second electrode is at a current density of 150 A/mm2 or higher and preferably a welding current of 600 A or higher, wherein one distance between the electrodes is 23 mm or more at the steel material surface position, and the other distances between the electrodes are 20 mm or less.