The structure and properties of steel 30KhGSA are studied after hardening by the quenching and partitioning (Q&P) process and, for comparison, by the standard modes of quenching and tempering. Metallographic and fractographic analyses and impact bending tests of the steel are performed. Kinetic diagrams of fatigue fracture are plotted, and the stress intensity factor ∆K and the rate of growth of fatigue crack v are computed. It is shown that the Q&P treatment yields a heterogeneous martensitic structure with interlayers of ductile retained austenite, which raises the impact toughness of the steel by a factor of 1.5 – 2 and the resistance to fatigue crack propagation by a factor of 1.5 as compared to the same characteristics after the traditional quenching and tempering. The strength of the steel remains virtually unchanged. The Q&P treatment may be recommended for raising the structural strength of heavily loaded machine parts.

30KhGSA 钢的组织和性能在淬火和分配 (Q&P) 工艺硬化后进行了研究，并通过标准的淬火和回火模式进行了比较。进行了钢的金相和断口分析以及冲击弯曲试验。绘制疲劳断裂动力学图，应力强度因子ΔK和疲劳裂纹扩展速率v被计算。结果表明，Q&P 处理产生了具有延展性残余奥氏体夹层的异质马氏体结构，与之前相比，钢的冲击韧性提高了 1.5-2 倍，抗疲劳裂纹扩展性提高了 1.5 倍。经传统调质后具有相同特性。钢的强度几乎保持不变。Q&P 处理可推荐用于提高重载机器部件的结构强度。