淬硬模具钢 Cr12MoV 因硬度、强度高以及淬透性好等特点在大尺寸模具制造中被广泛应用，但在高循环应力和大冲击载荷的服役工况下，其耐磨性有待进一步提高。 热处理可以在不改变材料成分的基础上通过改变内部组织来改善材料的强度、硬度和耐磨性，进而提升其使用性能。 本论文研究了深冷处理温度对 Cr12MoV 合金硬度和摩擦学性能的影响。 结果表明， Cr12MoV 合金经过深冷处理之后，表面硬度较未深冷处理试样高 1~2 个 HRC ，并且 -65 ℃ 深冷处理之后摩擦系数从 0.7 下降至 0.59 ， -196 ℃ 深冷处理之后摩擦系数进一步下降至 0.54 ， 磨损体积降低了五倍，而合金在不同温度下深冷处理之后表面硬度和磨损体积变化不大，从原子力显微镜观察到 -196 ℃ 深冷处理的样品表面有更细小、弥散的物相析出。 结合相关理论阐述了深冷处理的作用机制，为 Cr12MoV 合金的生产和应用提供理论指导。

Hardened die steel Cr12MoV is widely used in the manufacture of large dies and molds because of its high hardness and strength as well as good hardenability, but its wear resistance needs to be further improved under service conditions of high cyclic stress and large impact load. Heat treatment can improve the strength, hardness, and anti-wear performance of the material by changing the internal organization without changing the material composition. A suitable heat treatment process is of great importance for improving its performance. In this paper, the effect of cryogenic treatment temperature on the mechanical and tribological properties of Cr12MoV alloy is investigated. The results show that the surface hardness of the Cr12MoV alloy is 1~2 HRC higher than that the original alloy after cryogenic treatment. The friction coefficient of the Cr12MoV alloy decreases from 0.7 to 0.59 after treatment at -65 ℃, and then decreases 0.54 after cryogenic treatment at -196 ℃. In addition, the wear volume decreases five times after cryogenic treatment, while the surface hardness and wear volume of the alloy remain almost constant after cryogenic treatment at different temperatures. Atomic force microscopy measurements show that finer precipates are dispersed on the surface of the sample treated with -196 ℃. The mechanism of cryogenic treatment is explained in combination with relevant theories to provide theoretical guidance for production and application.