Microstructural development and mechanical properties during hot rolling and annealing of an automotive steel combining TRIP/TWIP effects

摘要

This research was carried out in order to study the variations of microstructure and mechanical properties of 9 wt% Mn steel, which was produced by ingot casting, hot rolling and intercritical annealing (IA). Thermodynamic simulation of the corresponding phase diagram for the experimental composition allowed to select a suitable intercritical annealing temperature of 680 degrees C. After this step, we found a microstructure composed by lamellar ferrite within an austenite matrix. Austenite content was 47% for the hot rolled sample, while it was 36% and 52% for two and 6 h of intercritical annealing, respectively.