Weld joint by laser-arc hybrid welding method using Ni-base alloy-based welding material and method for producing the same

摘要

PROBLEM TO BE SOLVED: To provide a laser arc hybrid welded joint in which no weld defects such as a pear-shaped bead crack and a surface crack occur and no fusion failures occur in an interface between a base metal and a weld metal in welding a thick steel plate base metal such as high Ni steel, and a method of manufacturing the laser arc hybrid welded joint.SOLUTION: A welded joint having a multi-pass weld metal is provided that is obtained by a welding method using laser arc hybrid welding in which a welding torch of gas shielded arc welding using a Ni-based alloy weld material is made to precede and a laser irradiation point is arranged behind the same. The welded joint is characterized in that, when WTA denotes the area of the whole weld metal and SWA denotes the sum of the areas of parts remelted by laser welding following the gas shielded arc welding, the area ratio SWA/WAT is 0.20 or more, and in that, when W and H respectively denote the width and the height of the weld metal formed for each one pas, all the H/W is less than 0.7, and in that an oxygen content of an obtained weld metal is 220 ppm or less.SELECTED DRAWING: Figure 3