Enhanced stability of retained austenite and consequent work hardening rate through pre-quenching prior to quenching and partitioning in a Q–P microalloyed steel

We propose a novel concept of introducing pre-quenching prior to quenching–partitioning (Q&Q–P), in a low carbon Nb-microalloyed Si–Mn steel, where the steel is first quenched from the austenizing temperature to the room temperature and prior to the Q–P treatment. The pre-quenching leads to smaller grain size and high fraction of stable retained austenite in the Q&Q–P processed steel. The martensitic transformation of retained austenite in the Q&Q–P sample takes place at a relatively higher strain and is characterized by a higher true stress as compared to Q–P processed steel.