Test of mechanical properties of high-strength Q460 steel at elevated temperatures and after fire exposure

Purpose In order to quantitatively evaluate the mechanical properties of high-strength Q460 steel at elevated temperatures and after fire exposure, tensile tests were conducted on Q460 high-strength steel at elevated temperatures and after fire exposure. Design/methodology/approach For the post-fire tensile tests, a constant tensile stress was applied during the heating and cooling stages of the specimen. The stress-strain curves for Q460 high-strength steel were recorded, from which the yield strength, ultimate strength and elastic modulus were obtained. Findings The results show that the strength decreases to 10% of its room-temperature value, while the elastic modulus remains at 40% at 800 °C. The post-fire residual strength of Q460 steel decreases sharply and the tensile stress has an approximately 10% adverse effect on the post-fire residual strength of high-strength Q460 steel when the exposure temperature is between 700 °C and 800 °C. Originality/value A series of constitutive models and predictive equations based on the test results are proposed to evaluate the mechanical properties of Q460 steel at high temperatures and after fire exposure.