HARDENED STEEL TUBE MEMBER AUTOMOBILE AXLE BEAM USING HARDENED STEEL TUBE MEMBER AND METHOD FOR MANUFACTURING HARDENED STEEL TUBE MEMBER

摘要

The quenched steel pipe member is formed of a GI galvanized steel pipe and has a cross section perpendicular to the longitudinal direction at a central portion in the longitudinal direction of the GI galvanized steel pipe with a contact portion in contact with the inner circumferential surfaces of the GI galvanized steel pipe And the contact portion is integrated by the Fe-Zn alloy phase, and the micro Vickers hardness at the depth of 50 mu m from the surface of the base material is 95% or more of the micro Vickers hardness at the depth of 200 mu m from the surface of the base material. %.