MG600锚杆钢的奥氏体晶粒长大规律

Austenite grain growth behavior of MG600 anchor steel

利用光学显微镜(OM)、扫描电镜(SEM)、热力学软件Thermo-calc等研究了MG600锚杆钢奥氏体晶粒的长大规律。结果表明:加热温度对晶粒长大的影响比保温时间更显著,温度越高晶粒长大速率越快,但长大速率受界面曲率的影响而不断减小。热力学计算证明较低温度下V(C,N)的析出是抑制晶粒长大的主要因素。随着温度的升高,V(C,N)溶解以后,奥氏体晶粒进入平稳长大阶段。借助Sellars方程建立的MG600钢奥氏体晶粒长大模型与试验实测值吻合较好,能够较好地预测不同温度下的奥氏体晶粒尺寸。

The austenite grain growth behavior in MG600 anchor steel was investigated by optical microscope,scanning electron microscope and thermodynamic software thermo-calc.The results show that the temperature has greater discernible impact on grain growth than the soaking time.The grain growth rate increases with the temperature,but it will slow down due to the effect of interface curvature.The thermodynamic calculation results show that the V(C,N)precipitation in low temperature is the dominant limiting factor in the austenite grain growth.It will enter the stable growth stage after the dissolution of V(C,N)with the temperature elevated.The austenite grain growth model in MG600 steel can be successfully established with the help of Sellars equation,with which the prediction results are in good agreement with experimental ones.The mathematical model could precisely predict the grain size with the temperature.