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本文对20Gr2Mo2V钢粒状贝氏体回火时的沉淀硬化过程进行了电镜观察,并分析了各强化的组织因素。发现在回火过程中,一方面贝氏体铁素体基体中有细小弥散的VC析出,且粗化相当缓慢。与此同时基体固溶含碳量降低。另一方面,“小岛”中的残余奥氏体转变成马氏体而岛中原有马氏体则逐步分解折出M_3C。对粒状贝氏体沉淀硬化效应的半定量估计表明,VC微粒的折出是产生强化的主要原因,“小岛”中残余奥氏体向马氏体的转变也对强化有一定贡献,而基体中含碳量的减少使固溶强化作用有所降低。
In this paper, the precipitation hardening process of 20Gr2Mo2V steel granular bainite tempering was observed by electron microscopy, and the strengthening of the organizational factors. Found in the tempering process, on the one hand, fine dispersed bainitic ferrite matrix VC precipitation, and the coarsening is quite slow. At the same time the matrix solid solution carbon content decreased. On the other hand, the residual austenite in the “island” is transformed into martensite and the original martensite in the island is gradually decomposed to M_3C. The semi-quantitative estimation of the precipitation hardening effect of granular bainite shows that the folding of the VC particles is the main reason for the enhancement. The transformation from retained austenite to martensite in “islands” also contributes to the strengthening, while the matrix Reduction of carbon content in the solid solution strengthening effect decreased.