JOINED BODY

摘要

A joined body formed by joining end surfaces of two joining members to each other by a friction welding, the joined body includes a hollow portion formed on at least one of the two joining members, the hollow portion being configured to have an opening at the joining face between the two joining members; and an annular groove portion formed on an inner circumferential surface of the hollow portion at a position separated from a joining face in an axial direction.