Abstract: Under the conditions of compression temperature of 950-1050 ℃(interval 50 ℃), prestrain of 0.1-0.2 s^-1(interval 0.05), strain rate of 0.01-1 s^-1, different prior grain sizes and different pass intervals, double-hit hot compression test of the 17CrNiMo6 steel was carried out on Gleeble-1500 thermo-mechanical simulator. The effects of pass interval, compression temperature, prestrain, strain rate and prior grain size on static recrystallization behavior of the 17CrNiMo6 steel were discussed. According to the microstructure of the specimens after compression and the flow stress curves of static recrystallization under different deformation conditions obtained by regression analysis, the static recrystallization kinetics model and grain size model of the 17CrNiMo6 steel were established. The results show that the volume fraction of static recrystallization increases with the increase of compression temperature, interval time, prestrain and strain rate. The grain size of static recrystallization increases with the increase of compression temperature and prior austenite grain size, while decreases with the increase of prestrain and strain rate. By comparing the predicted results by the models with the experimental values of thermal compression test, it is found that the two are in good agreement, which proves the accuracy of the models is high.

Key words: 17CrNiMo6 steel, double-hit hot compression test, static recrystallization, kinetic model, grain size model