| 摘要 |
PROBLEM TO BE SOLVED: To provide a structural member for an automobile obtained by projection welding of a high strength steel sheet and a weld nut or a weld bolt, which is excellent in a delayed fracture characteristic and a static strength characteristic of a welded part, and to provide a method for manufacturing the same. SOLUTION: The high strength steel sheet 1 and the weld nut or the weld bolt are joined by the projection welding, and the weld nut or the weld bolt includes a flange part whose lower surface side is made as a joint surface with the high strength steel sheet 1. On the joint surface, projection parts in a substantially semispherical shape are arranged. Moreover, when a center on a semicircular chord formed by crossing of the substantially semispherical arc of the projection part and the joint surface in cross section is C, and a radius of the projection part is R (mm), a recess is arranged within the range of a distance from the center C to 3R. The recess is arranged locally around the projection part. The total volume of the recesses falls within the range of 0.7-1.3 times that of the projection parts. COPYRIGHT: (C)2012,JPO&INPIT |
