| 摘要 |
PROBLEM TO BE SOLVED: To provide a friction stir welding method in which hollow cylindrical members are welded with each other without impairing any roundness of the hollow cylindrical members in their circumferential welding. SOLUTION: In welding the two hollow cylindrical members 3 and 4, a first probe 12 of a first rotary tool 1 and second probe 22 of a second rotary tool 2 are used, the pressing position of the first probe to a circumferential surface of the member and the pressing position of the second probe to a circumferential surface of the member are set to be in a plane orthogonal to the axes of the hollow cylinders at an angle of about 90 deg. therebetween. The members are welded with each other by moving the probes on the circumference of the members while being rotated. The pressure and the speed of rotation of the first and second probes are controlled to be same, respectively. |
