Friction stir welding tool with groove on a shoulder surface; Friction stir welding apparatus with such tool

摘要

The present invention relates to a bobbin tool including: a first shoulder surface (32) which comes into contact with a front surface of a subject work piece; a second shoulder surface (35) which is disposed so as to face the first shoulder surface (32) and comes into contact with a rear surface of the work piece; and a shaft portion (37) which connects the first shoulder surface (32) and the second shoulder surface (35) to each other with a gap therebetween fixed, the first shoulder surface (32) and the second shoulder surface (35) are provided with a first vortex groove (33) and a second vortex groove (36) which extend toward the front side of a tool rotation direction (R) so as to be opened to the outer peripheral edge as it moves to the outer peripheral side.