304 stainless steel (SS 304), as a high-temperature resistant material, has attracted widespread attention. To investigate the high-temperature rheological behavior of SS 304, isothermal hot compression tests were conducted using the Gleeble-3800 thermal simulation machine at temperatures ranging from 800 to 1200 °C, strain rates of 0.01 to 10 \(\:{s}^{-1}\) , and a deformation of 60%. Based on the experimental data, the Johnson–Cook (JC) constitutive model was established and modified. By incorporating the coupling effects of strain, strain rate, and temperature, a more accurate constitutive equation was proposed. The results show that the modified JC model provides better predictions of the rheological behavior of SS 304, with a correlation coefficient (Rco) of 0.9884 and an average absolute relative error (AARE) of 8.452%, indicating high prediction accuracy. The modified model was validated using ABAQUS. This study provides important theoretical references for the hot processing of SS 304 and help accurately calculate the material’s stress response at high temperatures, thereby optimizing processing parameters and enhancing material performance.
