This application provides a quenched and tempered steel plate and its production method. The quenched and tempered steel plate comprises the following components by
mass percentage: C: 0.15–0.20%; Si: 0.20–0.40%; Mn: 1.20–1.50%; Cr: 0.20–0.50%; Ni: 0.10–0.20%; Nb: 0.020–0.040%; Ti: 0.010–0.040%; Mo: 0.30–0.50%; B: 0.0010–0.0025%; P≤0.015%, S≤0.004%; N≤0.004%, Als: 0.010–0.060%, with the remainder being Fe and unavoidable impurities. This application manufactures a thick, high-strength quenched and tempered steel plate with
high surface quality by adjusting the
elemental composition and content of the quenched and tempered steel plate, specifically by adding certain amounts of Ni, Cr, and B.