FRICTION STIR WELDING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a friction stir welding method which lightens a load on a friction stir device so as to be capable of joining a deep position of a butting part.SOLUTION: A friction stir welding method joining two metallic members 1 by use of a rotary tool F including a stirring pin F2 comprises: a primary joining step in which the stirring pin F2 rotating is inserted into a butting part where the metallic members 1 are abutted and friction stir welding is performed in a state where only the stirring pin F2 contacts with the metallic members 1; a recessed groove formation step in which a recessed groove is formed on a surface of plasticized area W formed in the primary joining step; an arrangement step in which an auxiliary member is arranged at the recessed groove; and an auxiliary member joining step in which the metallic member 1 is joined with the auxiliary member.