| 摘要 |
The objective of the present invention is to form a strong joint while solving the problem whereby indentations remain and mar the external appearance. In this friction stir welding method a pair of plate materials (3, 4) are arranged opposing one another such that the ends thereof (3a, 4a) are butted together, after which friction stir welding is performed. A first shoulder (5) is arranged at one surface (7) of the pair of plate materials (3, 4) and a second shoulder (6) is arranged at the other surface (8) of the plate materials (3, 4) so as to sandwich therebetween a joint (S) to be formed by friction stirring of the end parts (3a, 4a) of the plate materials (3,4), and the first shoulder (5) and the second shoulder (6) are rotated, thereby friction stirring the joint (S) of the pair of plate materials (3, 4). As the joint (S) is friction stirred the first shoulder (5) and the second shoulder (6) are moved from the other surface (8) toward the one surface (7) of the plate materials (3, 4), thereby forming at the joint (S) a protruding part (31) protruding from the one surface (7) of the plate materials (3, 4) as the friction stir welding is performed. |
