| 摘要 |
PROBLEM TO BE SOLVED: To provide a friction stir welding method capable of making friction stir welding on curved sections of butting sections of a pair of hollow flat tubes while there are no defects on the curved sections of the butting sections of the pair of hollow flat tubes.SOLUTION: In a friction stir welding method, when the curvature radii r of the curved butting sections 3R1, 3R2 are set up to be one half or more of a thickness t of flat tubes (hollow flat tubes) 1, 2 and the part of the position of one half of the thickness t of the flat tubes 1, 2 and the distance from ends e of the flat tubes 1, 2 at a positional section at one half of the thickness t of the flat tubes 1, 2 is set up to be a relative rotary center O between the flat tubes 1, 2 and the rotary tool 4, and the flat tubes 1, 2 and the rotary tool 4 are relatively rotated around the rotary center O, and the curved butting sections 3R1, 3R2 are connected with friction stir welding by means of the rotary tool 4. |
