Heat treatment process for hot work die steel

The invention aims to provide a heat treatment method for the hot work die steel of 4Cr5Mo3Co2SiV. According to the process, the quenching heat treatment process is carried out at the temperature of 1050-1080 DEG C, the temperature is kept for 0.5-1 hour, oil cooling is carried out; the tempering heat treatment process is carried out at the temperature of 520-570 DEG C, the temperature is kept for 1.5-2.5 hours, and oil cooling is carried out; and the secondary tempering heat treatment is carried out at the temperature of 200 +/-10 DEG C, the temperature is kept for 1.5-2 hours, and oil cooling is carried out. Compared with the prior art, the hot work die steel treated by the method has better mechanical properties. 本发明的目的在于提供种热作模具钢4Cr5Mo3Co2SiV的热处理方法，其中，淬火热处理工艺为：1050℃～1080℃下保温0.5～1h，油冷；回火热处理工艺为：520～570℃下保温1.5～2.5h，油冷；二次回火热处理：200±10℃，保温1.5～2h，油冷。与现有技术相比，采用该方法处理过的热作模具钢具有更好的力学性能。