Effect of Nb on Austenite Recrystallization in High Temperature Deformation Process

By analyzing the stepped test pieces with optical microscope, the influence of the technological parameters including rolling temperature and reduction on the austenite recrystallization fraction of steel with Nb content of 0.08% deformed at high temperature processing was studied, and the deformed austenite recrystallization figures of the test steel were obtained. The result indicates that when the reduction is 60%, the critical temperature of complete recrystallization is 1070 ℃ and the borderline temperature of non-recrystallization is 900 ℃. In contrast with general HSLA steel, the recrystallization and non-recrystallization temperatures are respectively 120 ℃ and 100 ℃higher than those of ordinary HSLA, so the steel with high content of Nb has better hot processing performance because Nb has great function of holding back recrystallization.