ADVANCED Q-P-T STEELS WITH ULTRAHIGH STRENGTH-HIGH DUCTILITY

The quenching-partitioning-tempering (Q-P-T) process was developed from quench- ing & partitioning (Q&P) process and their difference are first described in this paper. The development of Q-P-T steels from ultrahigh strength to high strength-ductility is summarized. Novel Q-P-T pro- cess and conventional quenching-tempering (Q-T) process and their different effects on mechanical properties are compared. The micro-mechanism of the ductility enhancement from retained austenite in unltrahigh strength steels during deformation is emphasized in discussion, which provides guidance for microstructural design and control on the further development of advanced high strength steels.