TACK WELDING METHOD IN LARGE-DIAMETER WELDED STEEL PIPE PRODUCTION PROCESS

摘要

Provided is a tack welding method whereby, when welding large-diameter welded steel pipes, welding speed can be increased and humping beads, burn through, and incomplete fusion can be avoided. In this tack welding method: tack welding is continuously performed on an edge section (1a) of an open pipe (1) during a large-diameter welded pipe production process; and gas-metal arc welding is performed whereby the distance between an outer surface of the edge section (1a) and a lower tip of a contact tip (2) is at least 25 mm and a welding current of at least 1,000 A is supplied to a solid wire (3) having a wire diameter of at least 4.8 mm that is attached to the contact tip (2) and used as the welding wire.