FRICTION STIR WELDED JOINT

摘要

In joining together workpieces having a curved shape in a travelling direction of a tool using friction stir welding by keeping a rear portion of a shoulder of the tool from interfering with the workpieces, the present invention is intended to curb reduction in plate thickness of the weld between the workpieces after welding and prevent reduction in strength of the weld even when the curved shape has a small radius or when the workpieces have small plate thicknesses. [Solution] A friction stir welded joint 1 is produced by friction stir welding performed by butting together two workpieces 2 and 3 having a curved shape in a travelling direction F of a rotating tool 4 and inserting the rotating tool 4 into a targeted joining portion of the workpieces 2 and 3, in which: a protrusion 5 having a sloped portion 5a is provided on an end portion of workpiece 3 which is located on an inlet side of the rotating tool 4; and the rotating tool 4 is inserted substantially vertically into the sloped portion 5a to perform the friction stir welding.