Failure behaviour of various pre-formed steel sheets with respect to the mechanical grain boundary properties

The forming history influences the mechanical properties and the formability of sheet metals. Numerous models and approaches have been published to implement this influence into FE-tools, based on isotropic damage or failure criterions. In this paper, the influence of a uniaxial pre-forming and a change in loading direction on the material parameters is investigated for two different steel grades in tensile tests. It was found, that a change in loading direction significantly affects the mechanical properties of the material. The force–displacement curves obtained from nanoindentation experiments were utilized to determine the flow curves for single grains as well as grain boundaries of the pre-formed materials. This was done by inverse parameter identification using finite element analysis.