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本文论述了30CrNi2MoVA钢在不同温度等温淬火和低温回火后,下贝氏体和马氏体混合组织对机械性能的影响。在Ms点以上等温,得到的<50%B_下+M混合组织,比在Ms点以下等温得到M+B_下的混合组织具有较高的强度和较好的韧性。这是因为,先形成的下贝氏体对原奥氏体晶粒有分割作用,使随后马氏体相变时形成的马氏体单元细化,同时形成的马氏体对先形成的下贝氏体铁素体有强烈压缩作用。采用310±10℃×90s等温淬火、250×回火是获得高强韧性的理想工艺。
This article discusses the mechanical properties of 30CrNi2MoVA steel after isothermal quenching and low temperature tempering at different temperatures, the lower bainite and martensite mixed structure. Above the Ms point isothermal, the resulting <50% B_ under + M mixed tissue, the M + B_ is lower than the Ms below the mixed tissue has a higher strength and better toughness. This is because the lower bainite formed first segregates the original austenite grains to refine the martensite unit formed during the subsequent martensitic transformation while the formation of the martensite pairs the previously formed lower Bainitic ferrite has a strong compressive effect. Using 310 ± 10 ℃ × 90s isothermal quenching, 250 × tempering is the ideal process to obtain high strength and toughness.