@article{36327, abstract = {{AbstractWith an innovative optical characterization method, using high-temperature digital image correlation in combination with thermal imaging, the local change in strain and change in temperature could be determined during thermo-mechanical treatment of flat steel specimens. With data obtained by this optical method, the transformation kinetics for every area of interest along the whole measuring length of a flat specimen could be analyzed by the generation of dilatation curves. The benefit of this innovative optical characterization method compared to a dilatometer test is that the experimental effort for the design of a tailored component could be strongly reduced to the investigation of only a few tailored thermo-mechanical processed specimens. Due to the implementation of a strain and/or temperature gradient within the flat specimen, less metallographic samples are prepared for hardness analysis and analysis of the microstructural composition by scanning electron microscopy to investigate the influence of different process parameters. Compared to performed dilatometer tests in this study, the optical method obtained comparable results for the transformation start and end temperatures. For the final design of a part with tailored properties, the optical method is suitable for a time-efficient material characterization. Graphical Abstract}}, author = {{Reitz, Alexander and Grydin, Olexandr and Schaper, Mirko}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, keywords = {{Metals and Alloys, Mechanics of Materials, Condensed Matter Physics}}, number = {{8}}, pages = {{3125--3142}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Optical Detection of Phase Transformations in Steels: An Innovative Method for Time-Efficient Material Characterization During Tailored Thermo-mechanical Processing of a Press Hardening Steel}}}, doi = {{10.1007/s11661-022-06732-z}}, volume = {{53}}, year = {{2022}}, } @article{23794, author = {{Westermann, Hendrik and Reitz, Alexander and Mahnken, Rolf and Schaper, Mirko and Grydin, Olexandr}}, issn = {{1611-3683}}, journal = {{steel research international}}, title = {{{Microstructure transformations in a press hardening steel during tailored thermo‐mechanical processing}}}, doi = {{10.1002/srin.202100346}}, year = {{2022}}, } @article{29811, abstract = {{In order to reduce CO2 emissions in the transport sector, the approach of load-adapted components is increasingly being pursued. For the design of such components, it is crucial to determine their resulting microstructure and mechanical properties. For this purpose, continuous cooling transformation diagrams and deformation continuous cooling transformation diagrams are utilized, however, their curves are strongly influenced by the chemical composition, the initial state and especially the process parameters. In this study, the influence of the process parameters on the transformation kinetics is systematically investigated using an innovative characterization method. The experimental setup allowed a near-process analysis of the transformation kinetics, resulting microstructure and mechanical properties for a specific process route with a reduced number of specimens. A systematic investigation of the effects of different process parameters on the microstructural and mechanical properties made it possible to reveal interactions and independencies between the process parameters in order to design a partial heating or differential cooling process. Furthermore, the implementation of two different cooling conditions, representative of differential cooling in the die relief method with tool-contact and non-contact areas, showed that the soaking duration has a significant influence on the microstructure in the non-contact tool area.}}, author = {{Reitz, Alexander and Grydin, Olexandr and Schaper, Mirko}}, issn = {{0921-5093}}, journal = {{Materials Science and Engineering: A}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, publisher = {{Elsevier BV}}, title = {{{Influence of thermomechanical processing on the microstructural and mechanical properties of steel 22MnB5}}}, doi = {{10.1016/j.msea.2022.142780}}, volume = {{838}}, year = {{2022}}, } @inproceedings{28440, author = {{Triebus, Marcel and Reitz, Alexander and Grydin, Olexandr and Grenz, Julian and Schneidt, Andreas and Erhardt, Rüdiger and Tröster, Thomas and Schaper, Mirko}}, booktitle = {{13th European LS-DYNA Conference 2021}}, location = {{Ulm}}, title = {{{Forming Simulation of Tailored Press Hardened Parts}}}, year = {{2021}}, } @article{29089, author = {{Westermann, Hendrik and Reitz, Alexander and Mahnken, Rolf and Grydin, Olexandr and Schaper, Mirko}}, issn = {{1617-7061}}, journal = {{PAMM}}, title = {{{Constitutive modeling of viscoplasticity including phase transformations for graded thermo‐mechanical processing}}}, doi = {{10.1002/pamm.202100041}}, year = {{2021}}, } @article{23803, author = {{Reitz, Alexander and Grydin, Olexandr and Schaper, Mirko}}, journal = {{Materials Data for Smart Forming Technologies}}, location = {{Freiberg}}, title = {{{Characterization of phase transformations during graded thermo- mechanical treatment of steel 22MnB5 by means of optical methods }}}, year = {{2021}}, } @inbook{23801, author = {{Reitz, Alexander and Grydin, Olexandr and Schaper, Mirko}}, booktitle = {{The Minerals, Metals & Materials Series}}, issn = {{2367-1181}}, publisher = {{Springer}}, title = {{{Phase Transformation Characterization by Means of High Temperature Digital Image Correlation for Graded Thermo-Mechanical Processing of Sheet Parts}}}, doi = {{10.1007/978-3-030-36628-5_7}}, year = {{2020}}, } @article{23797, abstract = {{Abstract Safety-relevant components in automobiles require materials that combine high strength with sufficient residual ductility and high-energy absorption. A graded thermo-mechanical treatment of the press-hardening steel 22MnB5 with graded microstructure can provide a material with such properties. Different austenitization temperatures, cooling and forming conditions within a sheet part lead to the development of microstructures with mixed phase compositions. To determine the resulting phase contents in such graded processed parts, a large number of dilatometric tests are usually required. With a non-contact characterization method, it is possible to detect local phase transformations on an inhomogeneously treated flat steel specimen. For press-hardening steel after heat treatment and thermo-mechanical processing, correlations between austenitization temperature, hot deformation strain, microstructure, and hardness are established.}}, author = {{Reitz, Alexander and Grydin, Olexandr and Schaper, Mirko}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, pages = {{5628--5638}}, publisher = {{Springer}}, title = {{{Characterization of Phase Transformations During Graded Thermo-Mechanical Processing of Press-Hardening Sheet Steel 22MnB5}}}, doi = {{10.1007/s11661-020-05976-x}}, year = {{2020}}, }