METHOD FOR WELDING OVERLAPPED PART, METHOD FOR MANUFACTURING LAP WELD MEMBER, LAP WELD MEMBER, AND COMPONENT FOR AUTOMOBILE

摘要

A method for welding an overlapped part in which a plurality of steel sheet members are welded together at the overlapped part and at least one of the steel sheet members contains a martensite structure, the method being provided with: a resistance spot welding step in which spot welds (10) having nuggets (12) are formed on the overlapped part; and a step for forming melted and solidified parts in which a laser beam is emitted, and melted and solidified parts (15) are formed so that the depth of the melted and solidified parts (15) is equal to or greater than 50% of the respective sheet thickness in the steel sheet member(s) containing the martensite structure at a position located 1 mm outward from the ends of the nuggets (12) during formation of the melted and solidified parts (15) that traverse the ends of the nuggets (12) between the nuggets (12) and a position located 3 mm or farther outward from the ends of the nuggets (12), whereby the spot welds of the overlapped part are inhibited from breaking at the HAZ-softened part.