High-strength and high-toughness Cr8 cold work die steel and preparation method thereof

The invention provides high-strength and high-toughness Cr8 cold work die steel and a preparation method thereof. According to the preparation method provided by the invention, the step A) of electric furnace smelting is firstly carried out, specifically, a1) melting, a2) oxidation, a3) pre-reduction and a4) tapping; b, LF furnace refining is conducted, specifically, b1, molten steel is fed into the furnace, and b2, power transmission reduction is conducted; and C) VD furnace vacuum refining, D) forging and E) spheroidizing annealing are conducted, and finally the high-strength and high-toughness Cr8 cold work die steel is obtained. According to the method, the steps are carried out in sequence, so that the obtained product has high heat treatment hardness and unnotched impact resistance, non-metallic inclusions are reduced, the structure uniformity and eutectic carbide uniformity are improved, and flaw detection is qualified. 本发明提供了一种高强高韧Cr8冷作模具钢及其制备方法。本发明提供的制备方法，先进行步骤A)电炉冶炼，具体包括a1)熔化→a2)氧化→a3)预还原→a4)出钢；再进行步