Effect of fire temperature on the performance of 304 stainless steel: mechanical property degradation and microstructural evolution

This study systematically investigated the mechanical property degradation law and oxidation damage mechanism of 304 stainless steel rolled plate under high-temperature fire environment. The results show that as the temperature increases, the material exhibits systematic mechanical degradation: hardness, tensile strength, and plasticity significantly decrease, mainly attributed to thermal softening effect and grain boundary weakening. The thickness of the oxide layer on the 1223 K ablated sample reaches 9.5-25.5 μm, which is significantly increased compared to 973 K and 1023 K. Through this study, it was found that after the ablation temperature exceeds 1023 K, the oxidation damage of 304 stainless steel samples will sharply increase, providing a key basis for the fire-resistant design of elevator landing doors and the replacement standards of components after a fire.