The novel quenching and partitioning processes concerned with the stabilization of carbon enriched austenite and provision of higher strength with higher toughness. The microstructural and mechanical properties of one-step quenched and partitioned 65Mn steel were investigated under various partitioning times, ranging from 30 to 600 s. The optical microscopy revealed that microstructure transformed from ferrite and pearlite to supersaturated lath martensite and retained austenite phases after one-step quenching and 30 s of partitioning. The unstable epsilon carbides were nucleated with the increase in partitioning time to 60 s and 180 s, whereas a further increase in partitioning time to 300 s transformed these unstable epsilon carbides into a stable cementite phase. Prolonged partitioning for 600 s produced carbon depleted martensite phase and nucleated ferrite phase. A maximum improvement of 88% in hardness and tensile strength and maximum reduction of 64% in elongation and 44% in impact toughness were achieved after 30 s of partitioning, compared to the as-received steel sample. On the other hand, partitioning for 600 s offered almost identical mechanical properties to the as-received steel. Partitioning for 180 s offered an optimum combination of mechanical properties of one-step quenched and partitioned 65Mn steel.

新的淬火和分配过程涉及富碳奥氏体的稳定化以及提供更高的强度和更高的韧性。在30到600 s的不同分配时间下，研究了一步淬火和分配65Mn钢的显微组织和力学性能。光学显微镜显示，显微组织从铁素体和珠光体转变为过饱和板条马氏体，并在一步淬火和分配30 s后保留了奥氏体相。随着分配时间增加到60 s和180 s，不稳定的ε碳化物被形核，而分配时间的进一步增加到300 s，这些不稳定的ε碳化物转变为稳定的渗碳体相。长时间分配600 s会产生贫碳马氏体相和有核铁素体相。与原样钢样品相比，在分配30 s后，硬度和拉伸强度的最大提高为88％，伸长率的最大降低为64％，冲击韧性的最大降低为44％。另一方面，分配600 s可提供与原钢几乎相同的机械性能。180 s的分区可将一步淬火和分区65Mn钢的机械性能最佳组合。600 s的分隔提供了与原钢几乎相同的机械性能。180 s的分区可将一步淬火和分区65Mn钢的机械性能最佳组合。600 s的分隔提供了与原钢几乎相同的机械性能。180 s的分区可将一步淬火和分区65Mn钢的机械性能最佳组合。