FILLET ARC WELDING JOINT AND METHOD FOR MANUFACTURING SAME

摘要

Provided is an arc welded joint having excellent fatigue strength in which the hardness of an upper layer of a weld toe portion is increased to suppress the occurrence of crack, and of which a heat-affected zone in a plate thickness direction is narrowed to suppress the development of crack. A method for manufacturing the same is also provided. A fillet arc welded joint formed by fillet arc-welding at least two metal members comprises a re-melted portion formed by laser irradiation in a region including a boundary of a weld toe portion of at least one metal member that has been fillet arc-welded and a heat-affected zone produced by the fillet arc welding of a surface of the metal member. The fillet arc welded joint is characterized in that the re-melted portion is in an area with a depth of not more than 1/2 of the plate thickness of the metal member from the surface of the metal member, wherein prior austenite has an average effective crystal grain size of not more than 20 μm in the heat-affected zone at a depth of 0.1 mm from a re-melted boundary portion, which is the boundary of the re-melted portion in the surface of the metal member, in the plate thickness direction of the metal member.