含铌齿轮钢的晶粒长大动力学

Kinetics of Austenite Grain Coarsening in Nb-Bearing Gear Steels

利用金相试验方法和理论模型研究了几种Nb微合金化齿轮钢的奥氏体晶粒长大动力学。结果表明，试验钢中Nb含量分别为w（Nb）=0％、0．04％、0．06％和0．08％，奥氏体化温度在900-1200℃范围，奥氏体化保温时间为15～600min条件下，由于NbC颗粒的钉扎晶界作用，齿轮钢中添加微量Nb，可有效阻止奥氏体晶粒粗化，而且随Nb含量的增加，晶粒细化效果越明显。

Austenite grain growth kinetics in several Nb microalloyed gear steels has been investigated by metallographic technique and theoretic model, w（Nb） =0.04%, 0. 06%, 0. 08% are added to gear steels respectively. The heat treatments were performed in the temperature range of 900 to 1 200℃ for holding times of 15 to 600 rain. The results indicate that Nb can successfully be used to suppress grain growth in gear steels because NbC is effective for grain boundary pinning, moreover, the more the Nb content is, the more obvious is the grain refinement.