Effect of Heat Treatment Temperature on the Microstructure and Mechanical Properties of 30% Cold-Rolled AISI 304 Austenitic Stainless Steel

Stainless steel is widely utilized across various industrial applications, including as an implant material, due to its favorable biocompatibility, excellent corrosion resistance, and adequate mechanical properties. However, under physiological conditions, the toughness of stainless steel tends to decrease. To enhance its mechanical performance, cold rolling combined with subsequent heat treatment is often employed. In this study, AISI 304 austenitic stainless steel was subjected to a 30% cold rolling reduction, followed by austenitizing at different temperatures (600 °C, 700 °C, 800 °C, 900 °C, and 1000 °C) and then quenched in water to room temperature. The results showed that the highest hardness and tensile strength were achieved in the 30CR-NHT (non-heat-treated) sample, with values of 382.677 HV and 1007 MPa, respectively. The greatest toughness was observed in the 30CR-HT 1000 °C sample, reaching 62.526 J. Meanwhile, the finest average grain size was recorded in the 30CR-HT 800 °C sample, measuring 3.621 μm. These findings indicate that both mechanical strength and microstructural characteristics of stainless steel implants can be significantly influenced by the combination of cold working and controlled heat treatment parameters.