Improving the ultimate tensile strength without loss of plasticity of quenching-partitioning steel by introducing hot deformation

Quenching and partitioning (Q&P) is a heat treatment process which can obtain high strength and good plasticity matching steels. In this study, hot axial rolling was introduced in the Q&P steel and the microstructure evolutions and mechanical behaviors were compared with traditional Q&P steel. The results show that the introduction of hot deformation can retain more austenite, produce higher dislocation density and promote the precipitation of transition carbides. The higher dislocation density and more closely spaced transition carbides increase the work-hardening rate, which can not only increase the ultimate tensile strength, but also ensure no loss of plasticity, that is, improve the comprehensive mechanical properties of the Q&P steel.