The invention discloses high-
toughness hot-rolled high-strength steel with the yield strength being 800 MPa and a manufacturing method of the high-
toughness hot-rolled high-strength steel. The chemical components of the high-
toughness hot-rolled high-strength steel comprise, by weight, 0.02-0.05% of C, 0-0.5% of Si, 1.5-2.5% of Mn, 0-0.015% of P, 0-0.005% of S, 0.02-0.10% of Al, 0-0.006% of N, 0.01-0.05% of Nb, 0.01-0.03% of Ti, 0.03-0.06% of Nb and Ti, 0.1-0.5% of Cr, 0.1-0.5% of Mo, 0.0005-0.0025% of B, and the balance Fe and inevitable impurities. According to the high-toughness hot-rolled high-strength steel, the
design thinking of ultra-low carbon
martensite is adopted, the grain size of
austenite is refined through compound addition of Nb and Ti, the
hardenability and the temper hardening resistance are improved through compound addition of Cr and Mo, and by utilizing the hot
continuous rolling technique, ultra-low carbon
martensite structures are obtained through direct
quenching or the low-temperature coiling technique; the yield strength of the high-strength structural steel can reach 800 MPa, quite excellent low-temperature
impact toughness can still be achieved within the temperature range from minus 80 DEG C to
room temperature, and the ballistic work can reach over 100 J at the temperature of minus 80 DEG C.