| 摘要 |
PROBLEM TO BE SOLVED: To provide excellent friction stir welding when plural joint lines are brought into friction stir welding at the same time and parts not requiring the friction stir welding coexist with each other. SOLUTION: There are two joint lines, and rotary tools 340A and 340B corresponding to the joint lines. In a part requiring for joining two joint lines, two joint tools are inserted in a joint part and shifted together. At a position P1 of a window 210, the rotary tool 340A is retracted from the joint part and friction stir welding is stopped. At a position P3 thereof, the rotary tool 340B is gradually retracted, shifted it and joined. At a position P4 thereof, shift of the rotary tools 340A and 340B is stopped, the rotary tool 340B is retracted and welding is stopped. Then, the rotary tools 340A and 340B are inserted, and shift is started again. The amount of insertion of the rotary tool 340B is larger than that in stop shifting the rotary tool. |
