Effect of Nb on Austenite Grain Growth in 10Cr-3Co-2W Martensitic Heat-Resistant Steel

The effect of Nb on austenite grain growth kinetics was investigated in 10Cr-3Co-2W martensitic heat-resistant steel under various tempering conditions (temperature and time). The results demonstrate that Nb effectively refines the austenite grain size; this result is attributed to the combined effect of Nb atom solute drag effect and pinning effect of NbC precipitates. Based on the measured values, an empirical model was developed to predict the grain growth behavior of this alloy system. In addition, the key conditions and parameters for application to the microstructure evolution model of MatCalc software were derived. Results will enable the prediction of grain size at different Nb contents and temperature parameters, and provide useful information for designing heat treatment processes and alloys.