980 mpa-grade hot-rolled ferritic bainite dual-phase steel and manufacturing method therefor

Abstract

A 980 MPa-grade hot-rolled ferrite bainite dual-phase steel and a manufacturing method therefor. The chemical components of the steel comprise, in percentage by weight, 0.15-0.30% of C, 0.8-2.0% of Si, 1.0-2.0% of Mn, 0-0.02% of P, 0-0.005% of S, 0-0.003% of O, 0.5-1.0% of Al, 0-0.006% of N, 0.01-0.06% of Nb, 0.01-0.05% of Ti, and the balance of Fe and inevitable impurities. In addition, the chemical components meet the following relations: 0.05%≤Nb+Ti≤0.10%, and 2.5≤Al/C≤5.0. The microstructure of the steel is made of ferrite and bainite. The average grain size of the ferrite is 5-10 μm, and the equivalent grain size of the bainite is less than or equal to 20 μm. The yield strength of the steel is greater than or equal to 600 MPa, the tensile strength of the steel is greater than or equal to 980 Mpa, and the ductility is greater than or equal to 15%.

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