Residual Mechanical Properties of Q235FR Steel Exposed to High-temperatures

Steel structures are commonly used in engineering projects and infrastructure. Steel structures should have high bearing capacity and be able to resist fire, earthquake, and corrosion. A new type of Q235 refractory steel has recently been developed in China, and the residual mechanical properties of steel structures are key indicators for estimating structural damage and reusability. Therefore, in-depth research is urgently needed. The yield stress, residual elastic modulus, ultimate tensile strength, and ultimate strain at room temperature to 900 °C and under air and water cooling conditions were detected. The residual mechanical properties of Q235FR steel were compared with other structural steels, and it was confirmed through experiments that they are closely related to temperature and cooling methods. In the case of the above cooling methods, the loss of mechanical properties can be negligible when exposed to temperatures up to 600 °C. When the temperature exceeds 600 °C, the high temperature and cooling method significantly impact the residual mechanical properties of Q235FR steel. The advantages of Q235FR steel are high strength, good ductility, strong corrosion resistance, and fire resistance. The suggested predictive equations could be used to accurately evaluate the residual mechanical properties of Q235FR steel at high temperatures.