【摘要】 利用热模拟试验机、OM和TEM研究了钒微合金化中锰马氏体耐磨钢的奥氏体晶粒长大行为，分析了不同加热温度和保温时间下第二相粒子的形貌、尺寸和粒径分布及其与奥氏体晶粒长大行为的交互作用。结果表明，在820℃保温10 s时，试样的平均奥氏体晶粒尺寸为3.98μm，继续保温3600 s后仅长大1.47μm，具有较强的抗粗化能力。这是因为基体中细小的V(C, N)粒子钉扎奥氏体晶界，抑制了奥氏体晶粒的长大。随着保温温度升高和时间的增加，V(C, N)粒子发生溶解和粗化，钉扎能力减弱，奥氏体晶粒快速长大。利用增加时间指数的新型Sellars模型，通过预设误差函数的新型计算方法，建立了两段奥氏体长大模型，其与传统Beck模型相比，预测精度大幅度提升。更多还原

【Abstract】 Medium manganese martensitic wear-resistant steel is a new type of wear-resistant steel with high hardenability and hardness; moreover, the controlling austenite grain size is of great significance for improving its comprehensive properties. In this study, the austenite growth behavior of vanadium microalloying medium manganese martensitic wear-resistant steel was systematically investigated using the Gleeble-3500 thermal simulation testing machine, OM, and HRTEM. The morphology, size, and particle size distribution of the second phase particles at different heating temperatures and holding times were analyzed. The influence of second phase particles on the growth behavior in austenite was also revealed. The results showed that the ultra-fine austenite grains with grain size of 3.98 μm were obtained when the sample was held at 820oC for 10 s. After holding for 3600 s, the average grain size of austenite only increased by 1.47 μm, and the austenite grains showed a strong ability to resist coarsening at820oC. This could be attributed to the fine V(C, N) particles which could pin the austenite grain boundary and inhibit the growth of austenite grains. Furthermore, when reheating temperatures and holding times increase, the dissolution and coarsening of V(C, N) particles lead to the decrease of pining ability and then to the rapid growth of austenite. A new Sellars model with a time index was used to establish austenite growth model using a new method with a predetermined error function. The accuracy of the prediction for austenite grain sizes with new Sellars model was greatly improved compared with the traditional Beck model.更多还原