700MPa-grade hot-rolled dual-phase steel and manufacturing method thereof

The invention belongs to the technical field of steel and iron material engineering, relates to high-strength hot-rolled dual-phase steel and a manufacturing method thereof, and particularly relates to 700MPa-grade hot-rolled dual-phase steel and the manufacturing method thereof. The 700MPa-grade hot-rolled dual-phase steel comprises the following chemical ingredients in percentage by weight: 0.08-0.12 percent of C, 0.1-0.3 percent of Si, 0.7-1.00 percent of Mn, 0.02-0.06 percent of Alt, 0.60-1.00 percent of Cr, 0.03-0.06 percent of P, 0.02-0.05 percent of Ti, smaller than or equal to 0.005 percent of S, smaller than or equal to 0.006 percent of N and the balance of Fe and inevitable impurities. By controlling a suitable content of C and Si, greatly reducing the content of manganese, adding Cr, Ti and P, strictly controlling the content of S and N, adding no precious micro-alloyed elements Nb and V and no precious alloy such as Mo and Ni, the 700MPa-grade hot-rolled dual-phase steel is greatly lowered in cost.