Structural Metals after Exposure to High Temperatures: Residual Mechanical Properties and Predictions

Most research works have focused on studying the postfire (after exposure to high temperatures) mechanical properties of either carbon steel, stainless steel, or aluminum alloy. There are few studies directly comparing the mechanical properties of these structural metals after exposure to high temperatures, and there is no universal predictive equation describing their postfire retention factors. Herein, mechanical properties of structural metals (i.e., carbon steel, stainless steel, and aluminum alloy) after exposure to high temperatures are experimentally investigated. The mechanical properties of these structural metals are compared and rigorously analyzed. Existing equations are assessed by comparing their predictions against the corresponding postfire retention factors of the coupon specimens. A unified equation for the postfire mechanical properties of structural metals is developed, proposing different sets of coefficients for various structural metals based on the new test data from this study and the existing literature. The unified equation generally provides a safe and convenient assessment method, enabling practical engineers to determine the mechanical properties of metal structures after exposure to high temperatures in terms of Young's modulus, 0.2% proof stress (yield strength), and ultimate strength.