A novel design to enhance the stability of local austenite and the volume fraction of retained austenite in a low-carbon Si Mn Q-P steel

Pre-quenching prior to intercritical annealing quenching and partitioning(Q-P) process was proposed to enhance the volume fraction of retained austenite and the mechanical properties of a low-carbon Si-Mn steel.The intercritical austenite exhibited a lath morphology due to the martensitic microstructure maintained prior to intercritical annealing.Consequently, the alloy element enrichment of intercritical austenite, in which the alloy element was aggregated at the austenitic boundaries and further diffused inside, improved the stability of intercritical austenite and decreased the Mof it.As a result, the fraction of retained austenite in steel was increased, which improved the mechanical properties of the experimental Q-P steel.