LAP WELDING METHOD, LAP JOINT, PRODUCTION METHOD OF LAP JOINT, AND AN AUTOMOBILE PART

摘要

The present invention addresses the problem of minimizing breakage due to cracking associated with a HAZ softening region during generally circular laser lap-welding as a substitute for resistance spot-welding, in order to lap a plurality of steel sheets including high-strength steel plates. It was discovered that the problem is solved by a lap-welding method for lapping a plurality of steel plates and forming a generally circular laser welded portion (1), wherein the occurrence of cracking associated with a HAZ softening region is minimized through irradiation with a laser in a linear pattern passing through the outer edge of the generally circular laser welded portion (1), forming a quench portion (8) in the steel plates.