Modeling flow stress and grain size of GCr15 bearing steel at hightemperature deformation near end of solidification

摘要

Hot-core heavy reduction rolling is an innovative technology for continuous casting billet at the end of solidification.The deformation characteristics of GCr15 bearing billet were investigated over the temperature range of 1000-1300℃ with the strain rate of 0.001-10 s^(-1) by the Gleeble 3800 thermo-mechanical simulator.Firstly,the true stress-strain data are calibrated by the friction correction method to acquire accurate parameters near the solidus.Then,the Laasraoui-type constitutive model and dynamic austenite grain size model are established by the thermal compression results and corrosion experimental results,and the predicted values of the experimental interval are obtained by using the models.Meanwhile,the accuracy of models is verified by comparing the predicted curves with the experimental data.Last but not the least,the dynamic parameters between solidus and liquidus are predicted by the two models,and the difficulty of experimental collecting near the melting point is solved.