WELDING METHOD OF FORMING RAW MATERIAL USING HIGH STRENGTH STEEL PLATE, LASER WELDING APPARATUS, FORMING RAW MATERIAL OBTAINED BY METHOD, FORMING METHOD, AND FORMED ARTICLE

摘要

PROBLEM TO BE SOLVED: To provide a welding method of a forming raw material, which improves a ductibility of a portion welded in advance of a high strength steel plate as a target workpiece, and then enhances a forming limit, and also to provide a laser welding apparatus, a forming raw material obtained by the method, and a forming method and a formed article by using the forming raw material.SOLUTION: The welding method of a forming raw material using a high strength steel sheet is characterized as follows. The welding method welds a forming raw material piling up two or more high strength steel sheets, and heats a welded part again. A second welding is performed at the neighborhood of a first welded part 7, substantially parallel with the first welded part 7, so that the second welded part 10 may become farther than the first welded part 7 from a portion deformed when forming. The reheating or the second welding is performed by using laser or by laser welding, further a distance is desirably made 1.5-2 mm. The method is suitably performed by the laser welding apparatus.