Abstract: A laser welding method includes a pretreatment process and a welding process. At least one metal member of the plurality of metal members is formed from a metal-plated steel plate in which a base metal has been covered with a coating material that has a melting point lower than the base metal. In the pretreatment process, with the position of the first metal member in the in-plane direction fixed, processing is performed from the front surface of the first metal member to form on the back surface, a protrusion that bulges from the back surface. Then, in the welding process, the first metal member in which a protrusion has been formed is superposed on a second metal member with the protrusion therebetween while maintaining the position in the in-plane direction, and laser light is irradiated on the superposed region to weld the plurality of metal members to each other.

Abstract: In a laser welding method, first, laser light is irradiated on one side surface of one of the metal members to form a protruding portion projecting from the other side surface on the opposite side. Next, a part of the protruding portion that was formed is melted by scanning the laser light to generate a metal melt flow toward a top of the protruding portion so as to form a protrusion. The protrusion projects farther from the other side surface than a height of the protruding portion that was initially formed. Then, the one of the metal member having the protrusion is superposed on another of the metal members so that the protrusion is interposed therebetween. Next, the laser light is irradiated onto a portion where the metal members are superposed to weld the metal members to each other.

Abstract: A laser welding device includes a laser irradiation unit, a visible light sensor and a control unit. The laser irradiation unit irradiates a laser beam. The visible light sensor detects an emission intensity of visible light that is emitted from a welded portion. The control unit can freely switch the operation of the laser irradiation unit between a welding mode for welding a plurality of metal members to each other by irradiating laser beam and an inspection mode for irradiating the laser beam again onto the welded portion as an inspection light. After the welding the metal members, the control unit switches the laser irradiation unit to the inspection mode to irradiate the laser beam again onto the welded portion as an inspection light. The control unit detects if a hole is generated after welding based on changes in the emission intensity of the visible light.

Abstract: In a laser welding method, first, laser light is irradiated on one side surface of one of the metal members to form a protruding portion projecting from the other side surface on the opposite side. Next, a part of the protruding portion that was formed is melted by scanning the laser light to generate a metal melt flow toward a top of the protruding portion so as to form a protrusion. The protrusion projects farther from the other side surface than a height of the protruding portion that was initially formed. Then, the one of the metal member having the protrusion is superposed on another of the metal members so that the protrusion is interposed therebetween. Next, the laser light is irradiated onto a portion where the metal members are superposed to weld the metal members to each other.

Abstract: A laser welding method includes a pretreatment process and a welding process. At least one metal member of the plurality of metal members is formed from a metal-plated steel plate in which a base metal has been covered with a coating material that has a melting point lower than the base metal. In the pretreatment process, with the position of the first metal member in the in-plane direction fixed, processing is performed from the front surface of the first metal member to form on the back surface, a protrusion that bulges from the back surface. Then, in the welding process, the first metal member in which a protrusion has been formed is superposed on a second metal member with the protrusion therebetween while maintaining the position in the in-plane direction, and laser light is irradiated on the superposed region to weld the plurality of metal members to each other.