Optimized Processing Method for Enhancing the Strength and Ductility of Austenitic Stainless Steel: A Combination of Cold Rolling and Cryogenic Treatment

In this study, 304 austenitic stainless steel was processed by cold rolling (CR) and subsequent cryogenic treatment (CT), and the microstructure and mechanical properties were compared with those subjected to CR without CT. The results show that both CR and CR + CT samples exhibit heterogeneous structures after annealing at 650 degrees C. Compared to CR samples, the microstructure of the CR + CT samples is finer and demonstrates superior mechanical properties, with higher yield strength (954 MPa) and ultimate tensile strength (1014 MPa). The higher yield strength in CR + CT samples is attributed to the increased existence of martensite, grain refinement, and higher dislocation density. In addition, the transformation-induced plasticity (TRIP) should be the main reason for the excellent ductility in both CR and CR + CT samples. Based on the comparison of the mechanical properties of the samples treated by various processes, it could be concluded that the combination of CR and CT gives the material a balanced enhancement of strength and ductility, making it a promising approach for high-performance materials.