Abstract
The roll levelling is a forming process used to remove the residual stresses and imperfections of metal strips by means of plastic deformations. During the process the metal sheet is subjected to cyclic tension-compression deformations leading to a flat product. The process is especially important to avoid final geometrical errors when coils are cold formed or when thick plates are cut by laser. In the last years, and due to the appearance of high strength materials such as Ultra High Strength Steels, machine design engineers are demanding a reliable tool for the dimensioning of the levelling facilities. In response to this demand, finite element analysis is becoming an important technique able to lead engineers towards facilities optimization through a deeper understanding of the process. Nevertheless, the most commonly used material models, isotropic hardening models, are not able to reproduce the material’s Bauschinger effect and the final numerical results are not accurate enough. In the present paper, the roll levelling simulation of a DP1000 steel is performed using a combined isotropickinematic hardening formulation, firstly introduced by Armstrong and Frederick and subsequently modified by Chaboche. For material parameters’ identification tension-compression tests and shear-tests have been realized and compared. Finally, the influence of the material model in the numerical results is analyzed by comparing a pure isotropic model and a combined Chaboche hardening model.