| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a weld joint capable of obtaining the weld joint having less difference in hardness between a weld metal and a base-material steel sheet, and having excellent forming workability without heat-treating a portion including the weld metal.SOLUTION: There is provided a method of manufacturing a weld joint formed by welding a plurality of base-material steel sheets 1a, 1b. The method of manufacturing the weld joint includes a welding stage of welding the base-material steel sheets at welding speed of 0.5 m/min or more using a direct diode laser 3 as a light source. The laser in which the shape of a condensed beam 5 in the half width of peak intensity is long in a welding direction, and the aspect ratio (welding direction/direction orthogonal to welding) of the length of the condensed beam 5 in the welding direction and that in the direction orthogonal to welding is in a prescribed range, is used as the direct diode laser 3. In the method of welding the weld joint, in the welding stage, the weld metal including 50% or more of ferrite having a particle size of 30-150 μm is formed. |
