980MPa-grade high-strength steel and preparation method thereof

The invention relates to the technical field of steel and iron manufacturing, in particular to enhanced pore-expanding 980MPa-grade high-strength steel and a preparation method thereof, and the enhanced pore-expanding 980MPa-grade high-strength steel comprises the following chemical components: 0.08%-0.18% of C, 0.2%-0.8% of Si, 1.8%-3.0% of Mn, 0.2%-0.6% of Cr, 0.1%-0.3% of Mo, 0.01%-0.04% of Ti, 0.03%-0.06% of Alt, less than or equal to 0.010% of P, less than or equal to 0.006% of S and the balance of iron. According to the method, Mo and Ti microalloying is adopted, fine Mo and Ti composite precipitates are formed in the later stage of continuous rolling and coiling, austenite grains are refined, then ferrite grains are refined, meanwhile, a ferrite matrix is strengthened by a precipitated phase in ferrite, and the hardness difference between the ferrite matrix and martensite is reduced; two-pass dephosphorization of rough rolling and finish rolling is adopted, so that the surface quality is guaranteed; an