Coated ultrahigh-strength steel with low spot welding crack sensitivity and manufacturing method therefor

Abstract

The present invention discloses coated ultrahigh-strength steel with low spot welding crack sensitivity, comprising a steel substrate and a zinc-containing coating on the surface of the steel substrate. The steel substrate contains Fe and inevitable impurity elements. The steel substrate further contains the following chemical elements in percentage by mass: 0.10-0.30% of C, 0.30-0.90% of Si, 1.00-2.20% of Mn, 0.001-0.003% of B, and 0.30-1.00% of Al. Correspondingly, the present invention further discloses a manufacturing method for the coated ultrahigh-strength steel. The coated ultrahigh-strength steel in the present invention can be effectively prepared by using the manufacturing method, the final yield strength is 600-850 MPa, the tensile strength is 980-1150 MPa, the uniform elongation is not less than 13%, and the elongation at break is not less than 15%.

Dependencies are inferred from the claim text.