High temperatures deformation and formability behavior of DP590 steel: mechanical characterization and modeling

In this study, the deformation and formability characteristics of DP 590 steel have been determined at high temperature. Firstly, theoretical uniaxial flow stress prediction has been studied by modified Arrhenius, Fields–Backofen, Khan–Huang–Liang and modified Fields–Backofen, type constitutive models in different test temperatures (773–1093 K) with strain rates (0.001–0.1 s −1 ). The flow stress behavior of DP590 steel has been well predicted by the KHL model compared to other models. Furthermore, traditional yield functions such as, Hill 1948 and Barlat 1989, have been formulated. Barlat 1989 exhibits better prediction ability for all test temperatures. Additionally, Nakazima tests have been conducted for experimental determination of formability behavior by means of Forming limit Diagram (FLD), surface strain distribution, limit dome height and thickness distribution. Forming test temperature has significantly affected the formability behavior of the alloy. For theoretical prediction of FLD, Marciniak–Kuczynski (M–K) model has been implemented with different combination of uniaxial constitutive modeling and the yield function. The M–K model with a combination of KHL model with the Barlat 1989 yield function has given the best predictability with a 0.05 average error for all forming test temperatures. Furthermore fractography of the post stretched specimens has revealed a ductile fracture for test temperatures.