| 摘要 |
PROBLEM TO BE SOLVED: To provide a friction spot welding method and a friction spot welding structure that enable friction welding strength to be secured for a friction weld zone in which two aluminum alloy sheets are superposed on a steel sheet and successively spot welded, and that ensure high corrosion resistance against contact corrosion of the friction weld zone. SOLUTION: The steel sheet W1 and the aluminum alloy sheet W2 are superposed, and a first welding tool, while being rotated, is pressurized to the aluminum alloy sheet W2, thereby the aluminum alloy sheet W2 is softened with frictional heat and is caused to flow plastically, and thus a first welding part is formed in which the boundary between the steel sheet W1 and the aluminum alloy sheet W2 is solid-phase welded. Then, the aluminum alloy sheet W3 is superposed on the aluminum alloy sheet W2 so as to cover the first welding part 30, and a second welding tool, while being rotated, is pressurized to the aluminum alloy sheet W3 at a position corresponding to the first welding part 30, thereby softening the aluminum alloy sheet W3 with frictional heat, causing the softened aluminum alloy sheet W3 to flow plastically for welding to form a second welding part 31. COPYRIGHT: (C)2007,JPO&INPIT |
