The Effect of Applied Compression Stress on Isothermal Phase Transformation Kinetics and Transformation Plasticity of Bainite for HQ785 Steel

Abstract

AbstractThe study of isothermal bainite transformation under the applied compression stress for the HQ785 steel was carried out on the Gleeble1500 thermal simulation test machine, according to the expansion curve of bainite transformation with different stress and isothermal temperature, the simulated calculation of the phase transformation kinetics and transformation plasticity is carried out. The results show that, the applied compression stress promotes bainite transformation, with the stress increased, the incubation period of phase transformation becomes shorter. With the stress increased, the parameter b of bainite transformation kinetics equation shows the tendency of increasing, however, the increasing rate of b-valued is different under the different isothermal temperature and applied stress. When the applied stress is in elastic range, phase transformation plastic coefficient K increased with the stress increased. The bainite transformation kinetics model was adopted to numerical simulation of the bainite transformation process, the results of which are in good agreement with the measured, which shows that the calculation model is correct.KeywordsBainitetransformation kineticstransformation plasticityHQ785 steel