New approach for the characterisation of sheet materials - a precondition for the use of new sheet materials and forming processes

Based on the demands to decrease drastically the fuel consumption, the use of lightweight materials and semi-finished products such as - aluminum, - magnesium, - high- and ultra-high strength steel materials, - innovative tailored blank concepts, becomes more and more important. These aspects has to be considered for the tool and process design especially for forming operations. On the other hand, new innovative technologies (e. g. press hardening, hydroforming, temperature-supported forming processes, high-speed forming processes) lead to additional demands to guarantee high-quality parts. The determination of relevant material parameters which describe accurately the forming behavior represents the precondition for the extension of the application of these new materials and these innovative forming processes. In this context, the consideration of the following features is of crucial importance: - forming temperature - forming speed - high forming levels Another demand is the use of the FE simulation as an effective tool for process design. To guarantee high-quality simulation results, accurate input data are required which describe these phenomena. The Fraunhofer Institute for Machine Tools and Forming Technology meets this challenge. Therefore, an integrated concept for the materials characterization was developed. It comprises established test methods as well as new innovative characterization concepts to consider also phenomena such as springback, anisotropy and Bauschinger effect. Based on this approach, information about the interactions between sheet material, lubricant and forming tool can be derived. The following paper gives an overview about these activities including - the new challenges for material characterization, - the development of new material testing methods and - the achievable effects concerning the accuracy of the FE simulation results.