| 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. |
