机车车轮用钢奥氏体晶粒的长大行为

采用金相显微镜和截距法，对不同加热温度和保温时间下机车车轮用钢的奥氏体晶粒长大行为进行研究，分析加热温度和保温时间对奥氏体晶粒尺寸的影响，应用简单动力学模型对奥氏体晶粒的长大过程进行分析，同时研究钢中第二相粒子变化对奥氏体晶粒长大的影响.随着加热温度的升高和保温时间的延长，奥氏体晶粒尺寸明显增加，加热温度对晶粒的长大影响更明显.奥氏体晶粒长大的动力学时间指数随着温度升高而增加且其值均接近理论值0.5；奥氏体晶粒长大和钢中第二相粒子AlN体积分数和尺寸的变化呈明显的相关性. 

Austenite grain growth behavior of locomotive wheel steel

Metallographic microscopy and intercept method were adopted to investigate the austenitic grain growth behavior of locomotive wheel steel at different heating temperatures and holding time. On the basis of analyzing the effects of heating temperature and holding time on the austenite grain size, a simple kinetic model was used to analyze the austenite grain growth process, and the influence of the evolution of second phase particles on the austenite grain growth was also discussed. It is found that the austenite grain size increases with the rise of heating temperature and the prolonging of holding time, but the influence of heating temperature is more obvious. The kinetic time exponent of austenitic grain growth increases with temperature rise and the value is close to the theoretical value of 1/2. Austenite grain growth and the volume fraction and size variation of second phase particles AlN in the steel have a significant correlation.