800 MPa-grade dual-phase steel with one steel for multiple purposes and regulation and control method of 800 MPa-grade dual-phase steel

A steel billet of the 800MPa-grade dual-phase steel comprises the following chemical components in percentage by weight: 0.09 to 0.12 percent of C, 0.7 to 0.9 percent of Si, 1.8 to 2.0 percent of Mn, 0.8 to 1.0 percent of Alt, 0.20 to 0.30 percent of Cr, 0.03 to 0.05 percent of Nb, 0.0015 to 0.0030 percent of B, less than or equal to 0.008 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.005 percent of N, less than or equal to 0.005 percent of O and the balance of Fe and other inevitable impurities. The method is used for producing hot-rolled 800MPa-grade ferrite/martensite dual-phase steel, hot-rolled 800MPa-grade ferrite/bainite dual-phase steel, cold-rolled 800MPa-grade ferrite/martensite dual-phase steel, cold-rolled 800MPa-grade ferrite/bainite dual-phase steel and hot-galvanized 800MPa-grade ferrite/bainite dual-phase steel. The invention discloses a method for regulating and controlling 800MPa-grade dual-phase steel with one steel for multiple purposes. The method compris