Patent ID: 8692152

Claim:
A laser lap welding method for a galvanized steel sheet, comprising: preparing two steel sheets in lapped configuration with no gap, at least one of which is the galvanized steel sheet, so that a galvanized layer thereof is located at an interface of the steel sheets; and irradiating a surface of any one of the two steel sheets in an overlapped region with a laser to perform lap welding, wherein said irradiating includes applying the laser to travel at a predetermined high power density and at a predetermined high traveling velocity selected proportionally to the power density, so as to partially and temporarily form an elongated hole, in which the length in the laser traveling direction is at least twice of the width, in a molten pool extending backward from a laser irradiation spot at least in the steel sheet on the surface side, whereby metal vapor produced by laser irradiation is vented through the elongated hole backward in a laser traveling direction and in a laser irradiation source side.