Constitutive Modeling of Flow Behavior and Processing Maps of a Low-Carbon Steel

In order to study the thermal deformation behavior of a low-carbon steel, the samples were subjected to a single-pass thermal compression test on the Gleeble-1500 thermal simulator. The compression temperature was 900-1200 °C, and the strain rate was 0.01-10 s⁻¹. Based on the experimental results, a strain-compensated Arrhenius constitutive model and a physical constitutive model based on dynamic recrystallization were established. The correlation coefficient and average absolute relative error were used to appraisal the accuracy of models. These models were compared and both models can be used to predict the hot deformation behavior of the test steel. Furthermore, processing maps were established at the strains of 0.2, 0.4, 0.6, 0.8 and 1.0 to study the optimal processing conditions for the tested steel. The processing maps imply that two plastic instability zones formed at the areas of low temperature with high strain rate and high temperature with high strain rate, where the hot working process should be avoided. The optimal processing conditions for the tested steel are 1100-1175 °C and 1.35×10⁻¹–6×10⁻¹ s⁻¹.