Abstract：The flow stress curves in the deformation temperature range of 850-1200℃, the strain rate of 0.001-10s-1 and the deformation degree of 60% were obtained by hot compression test of A100 ultra-high strength steel on Gleeble-3500 thermal mechanical simulator. The effect of friction and temperature rise on the flow stress during the hot compression process was analyzed, and the flow stress curves were corrected. Phenomenological constitutive model based on introducing the strain parameter was established by the Arrhenius hyperbolic sine function equation. The results show that the influence of friction and temperature rise on the flow stress is gradually obvious with the decrease of deformation temperature or the increase of strain rate. Through comparison between experimental and predicted values, the absolute average relative error is 4.902% and the correlation coefficient is 0.99. It is revealed that the established constitutive model can accurately predict the flow stress under different strains.
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