Constitutive Modeling of a Nb-Contained Advanced High-Strength Steel (AHSS) under Hot Compression Experiments

In this study, the evaluation of hot forming behavior of an advanced high-strength steel (AHSS), namely Nb-Contained dual phase (DP) steel, is carried out using hot compression tests at temperatures of 850, 900, and 950ºC with strain rates of 0.001, 0.01, and 0.1 (s-1). The resulting flow curves indicated the occurrence of dynamic recrystallization (DRX) at all different conditions of testing. Furthermore, based on the measured stress-strain data, material constants and activation energy (Q) were calculated for the peak stress. Additionally, the values of these constants were estimated for different true strains and the correlation between them and the strain has been illustrated by various diagrams. The comparison shows that the derived Arrhenius equation has an accepted accuracy for predicting the values of flow stress.