Effect of intermediate annealing on microstructure and mechanical property of a Fe−19Mn−0.6C TWIP steel

Abstract

Abstract Annealing is an effective strategy to improve the properties of high-strength twin-induced plasticity (TWIP) steels, however, the adaption of intermediate annealing during cold rolling (CR) is scarcely studied. Here, the Fe-19Mn-0.6C TWIP steel was subjected to CR-annealing and CR-intermediate annealing-CR-annealing processes at room temperature to determine the role of intermediate annealing in the improvement of microstructure and mechanical properties. The total cold-rolled reduction in both processes is 75%. The morphological and phase characterizations of the TWIP steel annealed for 1 h showed that uneven element distribution had occurred as the annealing temperature was greater than the recrystallization start temperature, causing the presence of minor carbides. Moreover, the carbides vanished at the recrystallization end temperature and were quantitatively analyzed content via the refined XRD. Finally, the recrystallized austenite grains completely replaced the cold-deformed microstructures. At the same total CR reduction of 75%, the TWIP steel exerted intermediate annealing facilitates the formation of twins, endowing the tensile strength vast increase. This would provide a significant reference to improve the mechanical properties of steels via annealing.