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For a reliable virtual assessment of the press hardening process, thermomechanically coupled simulations have to be conducted. In this work a staggered solution procedure is employed for the coupling of the thermal and the mechanical system. Based on extensive experimental studies, the plastic flow behavior of the boron-alloyed steel 22MnB5 in the austenitic regime is characterized. Different mathematical models for the definition of the yield stress as a function of temperature, strain rate and plastic strain are examined. The parameters of these flow stress models are determined by inverse analysis. The coefficient of thermal expansion for the heating and the cooling phase is identified by dilatometry. Also based on dilatometer tests a CCT diagram for 22MnB5 is assembled. The temperature distribution and history within the blank are mainly determined by the thermomechanical interaction of the blank with the tools. Therefore the heat transfer coefficient between the blank and the tools is investigated for different contact scenarios. It is either defined as a function of the height of the air gap between the contact partners or as a function of the contact pressure. The determination of the heat transfer coefficient is carried out analytically as well as by inverse analysis. Furthermore input values for the convection coefficient as well as the radiation to the environment are estimated using empirical approaches and experimental data. The temperature dependent Coulomb friction coefficient for contact of the zinc-coated blank with the tools is determined with pin on disc tests in a tribometer. In addition to that the adequate modeling of the blank and the tools for the thermomechanically coupled simulation of the press hardening process is examined. As a result of these investigations, different modeling approaches are recommended for sheet and tools in the thermal and mechanical part of the simulation. To be able to efficiently simulate the complete press hardening process it is broken up in several process steps. For each of these process steps a specific simulation strategy is proposed. In order to illustrate this approach, the direct as well as the indirect press hardening process is simulated for a test part. The simulation results are in good agreement

Simulation des Presshärteprozesses und Vorhersage der mechanischen Bauteileigenschaften nach dem Härten