A new mathematical model for predicting flow stress of X70HD under hot deformation

Abstract

To realize numerical simulation of rolling and obtain the hot forming process parameters for X70HD steel, the flow stress behaviors of X70HD steel were investigated under different temperatures (820−1100 °C) and strain rates (0.01−10 s⁻¹) on a Gleeble-3500 thermo-simulation machine. A new flow stress model was established. The linear and exponential relationship methods were applied to the parameters with respect to temperature and deformation rates. The rise of curve ends under certain conditions was analyzed. The flow stress of X70HD steel predicted by the proposed model agrees well with the experimental results. So, it greatly improves the precision of the metal thermoplastic processing through finite element method and practical application of engineering.

Keywords

flow stress / dynamic recovery / dynamic recrystallization / Z parameter

References

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