METHOD OF WELDING TACK WELDS IN THE PRODUCTION OF WELDED STEEL PIPE OF A LARGER DIAMETER

摘要

Provided is a tack welding method that, in welding of a large-diameter welded steel pipe or tube, enables an increase in welding speed while preventing humped beads, burn through, and incomplete fusion. In the tack welding method, tack welding is performed continuously on edges (1a) of an open pipe or tube (1) in a production process for a large-diameter welded steel pipe or tube. The tack welding is performed by gas metal arc welding in which a welding current of 1000 A or greater is supplied to a solid welding wire (3) of 4.8 mm or greater in diameter that is attached to contact tip (2), while maintaining a distance of 25 mm or greater between an outer surface of the edges (1a) and a lower end of the contact tip (2).