Thermo-mechanical simulation of hard turning with macroscopic models and phase-field-models

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Compared to grinding is hard turning an advantageous alternative manufacturing process with respect to high chip removal rates, flexibility in case of geometrically complex work pieces and dry processing resource efficiency. The physical properties of the work piece material, which are relevant for the future component behavior, are essentially influenced by the surface layer formation, the phase transformations during the hard turning process and the development of residual stress. The process optimization of hard turning concerning the work piece thermal load requires the simulative mapping of these phenomena. Hence, the simulation of viscoplastic deformation processes taking into account the phase transformations in the work piece material by the use of a Multi-Mechanism-Model represents one of the main goals of the proposed project. The model validation is carried out on the basis of high speed and phase transformation experiments as well as in-situ temperature and resultant force component measurements. Moreover, phase-field models are used in order to achieve a better understanding of the phase transformations at the mesoscale such as austenitization, martensite formation and development of anisotropy. The research work within the first period of support focuses on the investigation of adequate simulation techniques that enable a realistic modeling of the thermal flux in rolling bearing rings during hard turning. In the second period of support, the results achieved in the first project phase are transferred to geometrically complex grooved turned parts with shaft shoulders. Furthermore, the development of an extensive material model taking into consideration the phase transformations, the phase plasticity and diffusion processes as well as enabling the derivation of thermally profitable machining strategies is intended. In the third period of support, the simulation models will be used to consider up- or downstream machining processes with the aim of deriving compensation strategies, which will lead to the reduction of thermal deformations by modifying the process control or the process sequence.