Abstract: A structural member usable for a car capable of demonstrating excellent flexural strength and absorbed energy performance and, moreover, capable of realizing weight reduction and is a structural member for a car being formed with a high-tensile steel pipe having a material property of not less than 1,400 MPa in tensile strength and not less than 5% in elongation. The structural member has a closed section structure which is provided as the configuration of the cross section perpendicular to the direction of the longitudinal axis. The cross-sectional configuration satisfies the following expression when a is defined as the maximum length of said cross-sectional configuration in the longitudinal direction, when b is defined as the maximum length thereof in the direction perpendicular to said direction, when L is defined as the circumferential length thereof, and when t is defined as the wall thickness of the steel pipe, 0.65?b/a?0.75, 0.014?t/L?0.

Abstract: The present invention provides a structural member for a car capable of demonstrating excellent flexural strength and absorbed energy performance and, moreover, capable of realizing weight reduction and is a structural member for a car being formed with a high-tensile steel pipe having a material property of not less than 1,400 MPa in tensile strength and not less than 5% in elongation, and also having a closed section structure as the configuration of the cross section perpendicular to the direction of the longitudinal axis, the cross-sectional configuration satisfying the expression (1) below when defining a as the maximum length of said cross-sectional configuration in the longitudinal direction, when defining b as the maximum length thereof in the direction perpendicular to said direction, when defining L as the circumferential length thereof and when defining t as the wall thickness of the steel pipe,