Effect of Microstructure Morphology of Q&P Steel on Carbon and Manganese Partitioning and Stability of Retained Austenite

In this study, we used 0.2C-1.7Si-1.9Mn wt% cold-rolled sheet as the experimental material to prepare Q&P sample with blocky microstructures and QQ&P lath-shaped through processes, respectively. The partitioning behavior of carbon manganese in two samples after intercritical annealing were studied. During annealing, occurred, resulting contents being significantly higher than those ferrite. Meanwhile, due migration ferrite–austenite interface during formation austenite, distributions austenite both homogenous. morphology had little influence on distribution metastable annealing. partitioning, diffusion can be ignored. Carbon first diffuses from ferrite grains then grains. has a great effect homogenization Compared coarse shorten path increase homogeneity grains, thereby improving thermal stability austenite. sample, content retained (14.74% vs. 13.96%), better elongation (25.9% 19.2%), product strength (27.5 GPa% 24.4 GPa%).