A lap fillet weld joint and a lap fillet weld joint manufacturing method are provided. On a side of a first edge, a first metal plate is provided with a bulging portion that has an internal space of a prescribed size, and a second metal plate has a protruding portion that faces to the bulging portion and can be inserted into the bulging portion. In a state in which the protruding portion has been inserted into the bulging portion, the first metal plate and a second edge of the second metal plate are welded, and a first weld bead is formed.

A lap fillet weld joint and a lap fillet weld joint manufacturing method are provided. On a side of a first edge, a first metal plate is provided with a bulging portion that has an internal space of a prescribed size, and a second metal plate has a protruding portion that faces to the bulging portion and can be inserted into the bulging portion. In a state in which the protruding portion has been inserted into the bulging portion, the first metal plate and a second edge of the second metal plate are welded, and a first weld bead is formed.

Irradiation with a laser beam is performed along a welding bead, while the laser beam is aimed, as an irradiation point of the laser beam, at a contact point between a deck plate and a U-rib that is contained in a non-welded portion of a root part, from a side of the welding bead of the root part. Thereby, it is possible to remove a crack beginning at the non-welded portion of the root part generated at a joining portion between the deck plate and the U-rib of a steel floor slab, by the irradiation with the laser beam.

A method of joining electrical connections together includes evaluating at least one weld joint between at least two substrates, determining a mismatch between the at least two substrates, and welding the at least two substrates together with a multi-step welding process. The multi-step welding process includes compensating for the mismatch between the at least two substrates by welding on both sides but not overlapping a joint line between the at least two substrate with a first welding step and increasing melt volume and penetration depth of a weld between the at least two substrates with a second welding step.

A method of joining electrical connections together includes evaluating at least one weld joint between at least two substrates, determining a mismatch between the at least two substrates, and welding the at least two substrates together with a multi-step welding process. The multi-step welding process includes compensating for the mismatch between the at least two substrates by welding on both sides but not overlapping a joint line between the at least two substrate with a first welding step and increasing melt volume and penetration depth of a weld between the at least two substrates with a second welding step.

A method of manufacturing a terminal-attached electric wire includes: installing an electric wire including a core wire including a plurality of element wires to a terminal having a conductor coupling part having a pair of barrel pieces, the core wire being installed between the pair of barrel pieces; bending the pair of barrel pieces to cause the pair of barrel pieces to wrap around and cover the core wire in a circumferential direction to form a slit extending in an axial direction between the pair of barrel pieces, with respect to the circumferential direction; melting the element wires of the core wire by emitting laser light toward the core wire through the slit; and adhering the element wires melted with the laser light to the conductor coupling part.

To enable welding in a state in which aluminum plating in a desired welding region is removed at a desired high accuracy, a plating layer (103) in a welding region (151) and a plating layer (104) in a welding region (152) are removed using an alkaline solution to form a preprocessed aluminum plated steel sheet (101a), and a plating layer (123) in a welding region (153) and a plating layer (124) in a welding region (154) are removed using an alkaline solution to form a preprocessed aluminum plated steel sheet (121a).

To enable welding in a state in which aluminum plating in a desired welding region is removed at a desired high accuracy, a plating layer (103) in a welding region (151) and a plating layer (104) in a welding region (152) are removed using an alkaline solution to form a preprocessed aluminum plated steel sheet (101a), and a plating layer (123) in a welding region (153) and a plating layer (124) in a welding region (154) are removed using an alkaline solution to form a preprocessed aluminum plated steel sheet (121a).

Provided is a butt laser-welding method for a metallic member in which a laser beam is scanned so as to repeatedly cross butting surfaces of metallic members to weld the metallic members to each other. When the laser beam is scanned so as to cross the butting surfaces, the closer the laser beam comes to the butting surfaces, the more an irradiation energy density of the laser beam is increased. The bottom surfaces of the molten pools formed on the metallic members are inclined so as to descend toward the butting surfaces.

Provided is a butt laser-welding method for a metallic member in which a laser beam is scanned so as to repeatedly cross butting surfaces of metallic members to weld the metallic members to each other. When the laser beam is scanned so as to cross the butting surfaces, the closer the laser beam comes to the butting surfaces, the more an irradiation energy density of the laser beam is increased. The bottom surfaces of the molten pools formed on the metallic members are inclined so as to descend toward the butting surfaces.