Automotive structural steel having a yield strength of equal to or greater than 1000 mpa and manufacturing method therefor

Abstract

An automotive structural steel having a yield strength of ≥1000 MPa and a manufacturing method therefor. The steel comprises, in percentage by weight, the components of: 0.15-0.23% of C, 0.12-0.5% of Si, 1.6-2.4% of Mn, 0.001-0.004% of B, 0.01-0.04% of Al, 0.05-0.5% of Cr, 0.15-0.5% of Mo, P≤0.015%, S≤0.005%, and the balance comprising Fe and other inevitable impurities, and needs to satisfy the following relations: the characteristic value Bs of the formation rate of lower bainite is 0.6-1.4, Bs=(Mo+B*100−Mn/5)/C; and the lower bainite in the microstructure thereof is ≥95%. The automotive structural steel has a yield strength of ≥1000 MPa, a tensile strength of ≥1180 MPa, an elongation of ≥7%, the 180° bending property d of ≤3.5T. The automotive structural steel of the present invention has ultra-high strength, and further has excellent formability, especially bending formability, thus being specifically suitable for manufacturing parts of an automotive chassis system.

Dependencies are inferred from the claim text.