Friction stir welding tool member, and friction stir welding method using the same

Abstract

A friction stir welding tool member according to the present embodiment has a shoulder portion and a probe portion concentrically projecting from an upper surface of the shoulder portion. The shoulder portion includes a curved surface processed portion that is curved to have a curved shape on an outer peripheral edge of the shoulder portion. A space occupancy occupied by the two-dimensional space in which neither the shoulder portion nor the probe portion exists is in a range of 30% to 70%, the space occupancy being determined based on a projection drawing of a side surface region surrounded from a tip of the probe portion to the curved surface processed portion of the shoulder portion.

Dependencies are inferred from the claim text.