Friction stir welding method

摘要

The end of a hollow member 10 is abutted against the end of a hollow member 20. The end of a face plate 21 is supported on a protrusion 15. A small-diameter portion 52 of a rotary tool 50 is inserted into the abutted area, and the tool 50 is moved along the abutted region while being rotated in a clockwise direction as observed from the large-diameter potion 51. Thus, the pressure of mobilized metal is greater on the right side of the axial center of the rotary tool. The thickness of the member from the tip of the inserted small-diameter portion 51 to the hollow areas 10b and 10a is thicker at the right side where the pressure is higher, thus preventing metal from flowing out into the hollow region 10a.