Preparation method of high performance ultra-thick steel plate

The invention discloses a preparation method of a high performance ultra-thick steel plate. The steel plate comprises the following components in percent by mass: 0.14% of C, 0.31% of Si, 1.45% of Mn, 0.02% of P, 0.003% of S, 0.020% of Nb, V and Ti and the balance of Fe. The method comprises the following steps: (1) controlling the carbon equivalent to smelt; (2) adopting the micro-alloying of Nb, V and Ti, refining in a ladle furnace and performing vacuum treatment; (3) pouring in a vertical-arc continuous casting machine to obtain a plate blank by the dynamic soft reduction technology; (4) controlling the inclusions of the steel blank; (5) heating; performing two-stage controlled rolling on a rolling mill, wherein the first-stage rolling technology adopts the austenitic recrystallization rolling technology and the second-stage rolling technology adopts the austenitic non-recrystallization area rolling technology; and (6) performing accelerated cooling. Compared with the prior art, by adopting the preparation method disclosed by the invention to produce the high performance ultra-thick special steel plate, the heat treatment cost and the alloy cost can be effectively reduced.