Hongshuang Di

Flow stress prediction for B210P steel at hot working conditions

Prediction of the flow stress is a significant step to optimize the hot working processes. In order to establish a proper deformation constitutive equation, the compressive deformation behavior of B210P steel was investigated at temperature from 950° to 1150° and strain rates from 0.1s−1 to 10s−1 on a Gleeble-2000 thermo-simulation machine. Based on the true stress-strain data from flow stress curves, a revised model describing the relationships of the flow stress, strain rate and temperature of B210P steel at elevated temperatures is proposed considering the effect of strain on flow stress. The activation energies have been in the range of 277.740-420.241kJ/mol for different amounts of strain. Finally, the accuracy of the developed constitutive equation has been verified using standard statistical parameters. The results confirm that the developed strain-dependent constitutive equation gives an accurate and precise estimate of the flow stress in the relevant deformation conditions.

On the Constitutive Modeling of the Hot Deformation Behavior of a High-Mn Twinning-Induced Plasticity Steel

The hyperbolic-sine model is commonly used to describe the constitutional relation between the strain rate, temperature and the peak or steady-state stress. However, for the purpose of modeling of the hot deformation behavior, the strain should be taken into consideration. In this study, the hot deformation behavior of a high-Mn twinning-induced plasticity steel was studied by using isothermal compression tests conducted in the temperature range of 900 to 1150 °C and strain rate range of 0.001 to 20 s−1. Based on the hyperbolic-sine model, the constitutive equations of the steel were developed by using the flow stress data. The strain was introduced in the constitutive equations through the material constants α, n, Q and A. Comparison of the flow stresses based on the constitutive equations with those obtained from the tests suggests that the developed constitutive equations can give a precise modeling of the hot deformation behavior of the steel investigated.