Patent ID: 8025200

Claim:
A friction stir welding tool for use in performing solid phase welding on a welding portion of materials to be welded, by pressing the welding tool against the welding portion of the materials to be welded while rotating the welding tool, and forcing the welding tool to be advanced into a softened portion which is softened by frictional heat while stirring the softened portion, wherein the welding tool includes a mounting portion having a first face and a second face, the mounting portion being configured to be inserted into a fitting recess formed at an end of a stirring rod of a friction stir welding machine, a first shoulder portion projecting from the first face of the mounting portion, a second shoulder portion projecting from the second face of the mounting portion, a first pin portion projecting from an end face of the first shoulder portion, and a second pin portion projecting from an end face of the second shoulder portion wherein the first and second shoulder portions and the first and second pin portions are coaxially disposed so as to be aligned with an axis of the stirring rod when the friction stir welding tool is removably attached to the end of the stirring rod.