Tensile mechanical properties of Q690D-QT at high temperatures and high strain rate

Through the steady-state test and high-temperature SHTB test of domestic high-strength steel Q690D-QT, the quasi-static and dynamic tensile mechanical properties of the steel at 20-700 ℃ were investigated. The steady-state test results show that the elastic modulus and the nominal yield strength f0. 2 and f0. 5(f0. 2 is the intersection point of the stress-strain curve and the proportional line offset by 0. 2% strain, f0. 5 is determined from the intersection of the stress-strain curve and vertical line at 0. 5% strain) decrease continuously with the increase of temperature, while the nominal yield strength f1. 0,f1. 5,f2. 0(f1. 0, f1. 5 and f2. 0 are determined from the intersection of the stress-strain curve and vertical line at 1. 0%, 1. 5%, and 2. 0% strain) and ultimate strength first increased slightly between 200-300 ℃ and then decreased continuously. The dynamic test results show that the strain rate effect of tensile yield strength at 700 ℃ is more significant than that at room temperature. With polynomial fitting, prediction formulae were obtained for the elastic modulus, yield strength, and ultimate strength reduction coefficient. The Johnson-Cook model parameters (A = 760 MPa, B = 402 MPa, n = 0. 534, C = 0. 004, m = 0. 966) were determined to describe the high-temperature dynamic tensile mechanical properties of Q690D-QT high-strength steel at temperature ranging from 20 ℃ to 700 ℃ and at a strain rate of 1 000 s - 1 © 2024 Science Press. All rights reserved.