Patent ID: 8820813

Claim:
A structural member for coupling by welding to another member, comprising: a hollow main tube part and at least two projecting portions formed integrally on an outer peripheral face of the main tube part, wherein the main tube part and the at least two projecting portions are formed by hydroforming an element tube having a tensile strength of 340 MPa or more and 850 MPa or less; and wherein the two projecting portions are disposed at an angle of 30 degrees or more and less than 180 degrees around a main axis of the main tube part, projecting planes of end faces of the respective projecting portions toward the main tube part share a plane perpendicular to the main axis of the main tube part only in portions of the projecting planes, areas of the portions of the projecting planes are 30% or more and 90% or less relative to areas of the respective projecting planes, and a projecting height of each of the two projecting portions is 0.3 D or more and 0.8 D or less, where D is an outside diameter of the element tube before hydroforming, and the main tube part includes a curved joining face which sequentially joins the two projecting portions and has a smooth curved face projecting inward of the main tube part or an oblique flat joining face which sequentially joins the two projecting portions and has an oblique flat face.