Effect of heating rate on microstructural evolution and mechanical properties of cold-rolled quenching and partitioning steel

Abstract

Quenching and partitioning (Q&P) processes were performed using initial heating rates ranging from 0.5 to 300 K s−1 with either one step or two steps in the intercritical annealing stage. Increasing the heating rate strongly affected the recrystallisation of ferrite and spheroidisation of pearlite. The nucleation and growth mechanisms of austenite under various heating rates were discussed, and the characteristics of retained austenite in each annealed sample were evaluated. Tensile tests demonstrated that the mechanical properties of Q&P steel increased with increasing heating rate. The poor mechanical properties of the slowly heated samples are suggested to result from the linable distribution of martensite.