High-toughness normalizing steel plate with 460MPa yield strength and manufacturing method thereof

The invention relates to the technical field of manufacture of medium steel plates, and discloses a high-toughness normalizing steel plate with 460MPa yield strength and a manufacturing method thereof. The high-toughness normalizing steel plate comprises the following chemical components by weight percent: 0.14%-0.20% of C, 0.20%-0.60% of Si, 1.20%-1.70% of Mn, 0.12%-0.20% of V, 0.15%-0.40% of Ni, 0.005%-0.020% of N, 0.005%-0.040% of Alt, less than or equal to 0.015% of P, less than or equal to 0.005% of S, and the balance of Fe and inevitable impurity. The manufacturing method disclosed by the invention comprises the steps of: heating a continuous casting blank to be at 1210-1240 DEG C by using a controlled rolling process and a normalizing process; controlling the total heating time according to 1.0-1.2min/mm; adopting a two-stage rolling mode, and controlling the initial rolling temperature of a non-recrystallization zone to be at 850-920 DEG C, and controlling the finishing temperature to be at 780-840 DE