Experimental investigation of high-temperature mechanical and creep properties of high-strength steel Q500qE

This study investigates the high-temperature mechanical properties and creep behavior of high-strength steel (HSS) Q500qE. High-temperature tensile tests (20 °C–700 °C) were conducted to determine reduction factors for yield strength, elastic modulus, ultimate strength, and elongation at break. At 700 °C, yield strength, elastic modulus, and ultimate strength decreased by 80 %, 53 %, and 81 %, respectively, while elongation at break increased by 210 %. New predictive equations with high regression coefficients were developed to estimate these reduction factors. High-temperature creep tests at 400 °C–600 °C under stress ratios of 0.4–1.0 were analyzed using the Norton-Bailey model, calibrated through nonlinear fitting. Results indicate that increasing temperature and stress ratio accelerate creep strain and shorten creep life. At 600 °C, even with a low stress ratio of 0.5, the specimen entered the accelerating creep stage and fractured within 549 min. The proposed predictive equations and calibrated model offer reliable estimates of Q500qE's high-temperature performance, providing valuable guidance for its application in elevated-temperature environments.