METHOD OF MANUFACTURING LASER WELDED STEEL PIPE

摘要

Provided is a method of efficiently manufacturing a high-quality laser welded steel pipe at a high yield ratio while occurrence of underfill is prevented. Specifically, welding is performed using multiple laser beams each having a spot diameter of 0.3 mm or larger on an upper surface of an open pipe (a surface of a steel strip), the plurality of laser beams being arranged such that the sum of spot lengths of the plurality of laser beams, the spot lengths extending perpendicularly to a welding line, on the surface of the steel strip is 0.5 mm or larger and such that a distance between spot centers of the plurality of laser beams in a direction of the welding line falls within 5 mm.

主权项

1. A method of manufacturing a laser welded steel pipe by forming a steel strip into a cylindrical open pipe with forming rolls and performing welding on edges of the open pipe by emitting a laser beam onto the edges from an outer surface side of the open pipe while pressing the edges with squeeze rolls, the method comprising: performing welding using a plurality of laser beams each having a spot diameter of 0.3 mm or larger on a surface of a steel strip, the plurality of laser beams being arranged such that the sum of spot lengths of the plurality of laser beams, the spot lengths extending perpendicularly to a welding line, on the surface of the steel strip is 0.5 mm or larger and such that a distance between spot centers of the plurality of laser beams in a direction of the welding line falls within 5 mm.