--- _id: '59907' abstract: - lang: eng text: Abstract. Flow forming is recognized for its precision in producing rotationally symmetric components, but the use of metastable austenitic stainless steel (AISI 304L) introduces challenges due to uncontrolled strain-induced α’ martensite formation. Variations in factors such as eccentricity and batch inconsistencies lead to unpredictable microstructural profiles, limiting reproducibility [1,2]. This study addresses these issues by incorporating thermal actuators for cryogenic cooling and induction heating to regulate forming temperatures, enabling control of the α’-martensite content. Experimental investigations demonstrate that local tempering during thermomechanical reverse flow forming produces discernible variations in microstructure, affecting mechanical and magnetic properties [3]. Controlled local adjustments of α’-martensite content allow for customization of properties in seamless tubes, advancing manufacturing capabilities for complex, defect-free components. The results presented demonstrate promising strategies for implementation within the context of closed-loop property control in flow forming. author: - first_name: Bahman full_name: Arian, Bahman id: '36287' last_name: Arian - first_name: Werner full_name: Homberg, Werner id: '233' last_name: Homberg - first_name: Lukas full_name: Kersting, Lukas last_name: Kersting - first_name: Ansgar full_name: Trächtler, Ansgar id: '552' last_name: Trächtler - first_name: Julian full_name: Rozo Vasquez, Julian last_name: Rozo Vasquez - first_name: Frank full_name: Walther, Frank last_name: Walther citation: ama: 'Arian B, Homberg W, Kersting L, Trächtler A, Rozo Vasquez J, Walther F. Advanced thermomechanical flow forming: A novel approach to α’-martensite control for enhanced material properties. In: Carlone P, Filice L, Umbrello D, eds. Materials Research Proceedings. Vol 54. Materials Research Forum LLC; 2025. doi:10.21741/9781644903599-127' apa: 'Arian, B., Homberg, W., Kersting, L., Trächtler, A., Rozo Vasquez, J., & Walther, F. (2025). Advanced thermomechanical flow forming: A novel approach to α’-martensite control for enhanced material properties. In P. Carlone, L. Filice, & D. Umbrello (Eds.), Materials Research Proceedings (Vol. 54). Materials Research Forum LLC. https://doi.org/10.21741/9781644903599-127' bibtex: '@inproceedings{Arian_Homberg_Kersting_Trächtler_Rozo Vasquez_Walther_2025, title={Advanced thermomechanical flow forming: A novel approach to α’-martensite control for enhanced material properties}, volume={54}, DOI={10.21741/9781644903599-127}, booktitle={Materials Research Proceedings}, publisher={Materials Research Forum LLC}, author={Arian, Bahman and Homberg, Werner and Kersting, Lukas and Trächtler, Ansgar and Rozo Vasquez, Julian and Walther, Frank}, editor={Carlone, Pierpaolo and Filice, Luigino and Umbrello, Domenico}, year={2025} }' chicago: 'Arian, Bahman, Werner Homberg, Lukas Kersting, Ansgar Trächtler, Julian Rozo Vasquez, and Frank Walther. “Advanced Thermomechanical Flow Forming: A Novel Approach to α’-Martensite Control for Enhanced Material Properties.” In Materials Research Proceedings, edited by Pierpaolo Carlone, Luigino Filice, and Domenico Umbrello, Vol. 54. Materials Research Forum LLC, 2025. https://doi.org/10.21741/9781644903599-127.' ieee: 'B. Arian, W. Homberg, L. Kersting, A. Trächtler, J. Rozo Vasquez, and F. Walther, “Advanced thermomechanical flow forming: A novel approach to α’-martensite control for enhanced material properties,” in Materials Research Proceedings, Paestum, Italy, 2025, vol. 54, doi: 10.21741/9781644903599-127.' mla: 'Arian, Bahman, et al. “Advanced Thermomechanical Flow Forming: A Novel Approach to α’-Martensite Control for Enhanced Material Properties.” Materials Research Proceedings, edited by Pierpaolo Carlone et al., vol. 54, Materials Research Forum LLC, 2025, doi:10.21741/9781644903599-127.' short: 'B. Arian, W. Homberg, L. Kersting, A. Trächtler, J. Rozo Vasquez, F. Walther, in: P. Carlone, L. Filice, D. Umbrello (Eds.), Materials Research Proceedings, Materials Research Forum LLC, 2025.' conference: end_date: 2025-05-09 location: Paestum, Italy name: The 28th International ESAFORM Conference on Material Forming - ESAFORM 2025 start_date: 2025-05-06 date_created: 2025-05-15T06:59:28Z date_updated: 2025-10-30T13:55:08Z department: - _id: '156' - _id: '153' - _id: '241' doi: 10.21741/9781644903599-127 editor: - first_name: Pierpaolo full_name: Carlone, Pierpaolo last_name: Carlone - first_name: Luigino full_name: Filice, Luigino last_name: Filice - first_name: Domenico full_name: Umbrello, Domenico last_name: Umbrello has_accepted_license: '1' intvolume: ' 54' keyword: - Flow Forming - Thermomechanical Forming - α’-Martensite - Property Control language: - iso: eng main_file_link: - open_access: '1' url: https://mrforum.com/product/9781644903599-127/ oa: '1' publication: Materials Research Proceedings publication_identifier: issn: - 2474-395X publication_status: published publisher: Materials Research Forum LLC quality_controlled: '1' status: public title: 'Advanced thermomechanical flow forming: A novel approach to α’-martensite control for enhanced material properties' type: conference user_id: '36287' volume: 54 year: '2025' ... --- _id: '23465' abstract: - lang: eng text: One of the main objectives of production engineering is to reproducibly manufacture (complex) defect-free parts. To achieve this, it is necessary to employ an appropriate process or tool design. While this will generally prove successful, it cannot, however, offset stochastic defects with local variations in material properties. Closed-loop process control represents a promising approach for a solution in this context. The state of the art involves using this approach to control geometric parameters such as a length. So far, no research or applications have been conducted with closed-loop control for microstructure and product properties. In the project on which this paper is based, the local martensite content of parts is to be adjusted in a highly precise and reproducible manner. The forming process employed is a special, property-controlled flow-forming process. A model-based controller is thus to generate corresponding correction values for the tool-path geometry and tool-path velocity on the basis of online martensite content measurements. For the controller model, it is planned to use a special process or microstructure (correlation) model. The planned paper not only describes the experimental setup but also presents results of initial experimental investigations for subsequent use in the closed-loop control of α’-martensite content during flow-forming. author: - first_name: Bahman full_name: Arian, Bahman id: '36287' last_name: Arian - first_name: Werner full_name: Homberg, Werner id: '233' last_name: Homberg - first_name: Markus full_name: Riepold, Markus last_name: Riepold - first_name: Ansgar full_name: Trächtler, Ansgar id: '552' last_name: Trächtler - first_name: Julian full_name: Rozo Vasquez, Julian last_name: Rozo Vasquez - first_name: Frank full_name: Walther, Frank last_name: Walther citation: ama: 'Arian B, Homberg W, Riepold M, Trächtler A, Rozo Vasquez J, Walther F. Forming of metastable austenitic stainless steel tubes with axially graded martensite content by flow-forming. In: ULiège Library; 2021.' apa: Arian, B., Homberg, W., Riepold, M., Trächtler, A., Rozo Vasquez, J., & Walther, F. (2021). Forming of metastable austenitic stainless steel tubes with axially graded martensite content by flow-forming. 24th International Conference on Material Forming - ESAFORM 2021, Liège, Belgium. bibtex: '@inproceedings{Arian_Homberg_Riepold_Trächtler_Rozo Vasquez_Walther_2021, place={Liège}, title={Forming of metastable austenitic stainless steel tubes with axially graded martensite content by flow-forming}, publisher={ULiège Library}, author={Arian, Bahman and Homberg, Werner and Riepold, Markus and Trächtler, Ansgar and Rozo Vasquez, Julian and Walther, Frank}, year={2021} }' chicago: 'Arian, Bahman, Werner Homberg, Markus Riepold, Ansgar Trächtler, Julian Rozo Vasquez, and Frank Walther. “Forming of Metastable Austenitic Stainless Steel Tubes with Axially Graded Martensite Content by Flow-Forming.” Liège: ULiège Library, 2021.' ieee: B. Arian, W. Homberg, M. Riepold, A. Trächtler, J. Rozo Vasquez, and F. Walther, “Forming of metastable austenitic stainless steel tubes with axially graded martensite content by flow-forming,” presented at the 24th International Conference on Material Forming - ESAFORM 2021, Liège, Belgium, 2021. mla: Arian, Bahman, et al. Forming of Metastable Austenitic Stainless Steel Tubes with Axially Graded Martensite Content by Flow-Forming. ULiège Library, 2021. short: 'B. Arian, W. Homberg, M. Riepold, A. Trächtler, J. Rozo Vasquez, F. Walther, in: ULiège Library, Liège, 2021.' conference: end_date: 2021-04-16 location: Liège, Belgium name: 24th International Conference on Material Forming - ESAFORM 2021 start_date: 2021-04-14 date_created: 2021-08-23T13:00:35Z date_updated: 2023-05-02T08:27:48Z department: - _id: '156' - _id: '153' - _id: '241' keyword: - Flow-forming - Spinning - Process Strategy - Martensite Content - Property Control - Micromagnetic Measurement - Metastable Austenitic Stainless Steel language: - iso: eng main_file_link: - open_access: '1' url: https://popups.uliege.be/esaform21/index.php?id=2759 oa: '1' place: Liège publication_identifier: eisbn: - 978-2-87019-303-7 isbn: - 978-2-87019-302-0 publication_status: published publisher: ULiège Library quality_controlled: '1' status: public title: Forming of metastable austenitic stainless steel tubes with axially graded martensite content by flow-forming type: conference user_id: '36287' year: '2021' ... --- _id: '9862' abstract: - lang: eng text: 'In order to improve the credibility of modern simulation tools, uncertainties of different kinds have to be considered. This work is focused on epistemic uncertainties in the framework of continuum mechanics, which are taken into account by fuzzy analysis. The underlying min-max optimization problem of the extension principle is approximated by α-discretization, resulting in a separation of minimum and maximum problems. To become more universal, so-called quantities of interest are employed, which allow a general formulation for the target problem of interest. In this way, the relation to parameter identification problems based on least-squares functions is highlighted. The solutions of the related optimization problems with simple constraints are obtained with a gradient-based scheme, which is derived from a sensitvity analysis for the target problem by means of a variational formulation. Two numerical examples for the fuzzy analysis of material parameters are concerned with a necking problem at large strain elastoplasticity and a perforated strip at large strain hyperelasticity to demonstrate the versatility of the proposed variational formulation. ' author: - first_name: Rolf full_name: Mahnken, Rolf last_name: Mahnken citation: ama: Mahnken R. “A variational formulation for fuzzy analysis in continuum mechanics.” Mathematics and Mechanics of complex systems. 2017;5(3-4). apa: Mahnken, R. (2017). “A variational formulation for fuzzy analysis in continuum mechanics.” Mathematics and Mechanics of Complex Systems, 5(3–4). bibtex: '@article{Mahnken_2017, title={“A variational formulation for fuzzy analysis in continuum mechanics”}, volume={5}, number={3–4}, journal={Mathematics and Mechanics of complex systems}, author={Mahnken, Rolf}, year={2017} }' chicago: Mahnken, Rolf. “‘A Variational Formulation for Fuzzy Analysis in Continuum Mechanics.’” Mathematics and Mechanics of Complex Systems 5, no. 3–4 (2017). ieee: R. Mahnken, “‘A variational formulation for fuzzy analysis in continuum mechanics,’” Mathematics and Mechanics of complex systems, vol. 5, no. 3–4, 2017. mla: Mahnken, Rolf. “‘A Variational Formulation for Fuzzy Analysis in Continuum Mechanics.’” Mathematics and Mechanics of Complex Systems, vol. 5, no. 3–4, 2017. short: R. Mahnken, Mathematics and Mechanics of Complex Systems 5 (2017). date_created: 2019-05-20T11:36:47Z date_updated: 2019-05-27T12:54:35Z department: - _id: '154' intvolume: ' 5' issue: 3-4 keyword: - fuzzy analysis - α-level optimization - quantities of interest - optimization with simple constraints - large strain elasticity - large strain elastoplasticity language: - iso: eng main_file_link: - open_access: '1' url: https://msp.org/memocs/2017/5-3/memocs-v5-n3-p03-s.pdf oa: '1' publication: Mathematics and Mechanics of complex systems publication_identifier: issn: - ' 2325-3444' publication_status: published status: public title: '"A variational formulation for fuzzy analysis in continuum mechanics"' type: journal_article user_id: '78813' volume: 5 year: '2017' ... --- _id: '34441' abstract: - lang: eng text: The state of the art industrial manufacturing process to produce shafts as counter surfaces for radial shaft seal rings is plunge grinding. This process consists of three major steps. The blank is turned to a slight diameter-oversize followed by the heat treatment and the hard-finishing by plunge grinding. The geometric surface structures of the resulting shafts in general exhibit a stochastic distribution. These surface characteristics contribute to a reliable and stable sealing functionality. And the surface and subsurface hardness generally leads to a higher wear resistance of the shaft. Motivated by economic benefits and in order to achieve a compact production process for at least ten years, turning is investigated as an alternative manufacturing process. However due to the resulting lead structure on the shaft surface and the associated risk of leakage it has not become prevalent yet. In this paper turned shafts of the metastable austenitic steel AISI 347 (1.4550, X6CrNiNb1810) are investigated as alternative material for counter surfaces of radial shaft seal rings and compared to turned shafts of carburized AISI 5115 (1.7131, 16MnCr5). In addition to surfaces dry turned at room-temperature, cryogenic turned AISI 347 counter surfaces are analyzed. By applying cryogenic cooling, the formation of deformation-induced α′-martensite in the surface layer is possible during the turning process. Endurance tests in radial shaft seal ring test rigs are performed and complemented with detailed investigations of microstructure, micro-hardness and surface topography. The results are compared to results of state of the art ground AISI 5115 shafts. author: - first_name: D. full_name: Frölich, D. last_name: Frölich - first_name: Balázs full_name: Magyar, Balázs id: '97759' last_name: Magyar - first_name: B. full_name: Sauer, B. last_name: Sauer - first_name: P. full_name: Mayer, P. last_name: Mayer - first_name: B. full_name: Kirsch, B. last_name: Kirsch - first_name: J.C. full_name: Aurich, J.C. last_name: Aurich - first_name: R. full_name: Skorupski, R. last_name: Skorupski - first_name: M. full_name: Smaga, M. last_name: Smaga - first_name: T. full_name: Beck, T. last_name: Beck - first_name: D. full_name: Eifler, D. last_name: Eifler citation: ama: Frölich D, Magyar B, Sauer B, et al. Investigation of wear resistance of dry and cryogenic turned metastable austenitic steel shafts and dry turned and ground carburized steel shafts in the radial shaft seal ring system. Wear. 2015;328-329:123-131. doi:https://doi.org/10.1016/j.wear.2015.02.004 apa: Frölich, D., Magyar, B., Sauer, B., Mayer, P., Kirsch, B., Aurich, J. C., Skorupski, R., Smaga, M., Beck, T., & Eifler, D. (2015). Investigation of wear resistance of dry and cryogenic turned metastable austenitic steel shafts and dry turned and ground carburized steel shafts in the radial shaft seal ring system. Wear, 328–329, 123–131. https://doi.org/10.1016/j.wear.2015.02.004 bibtex: '@article{Frölich_Magyar_Sauer_Mayer_Kirsch_Aurich_Skorupski_Smaga_Beck_Eifler_2015, title={Investigation of wear resistance of dry and cryogenic turned metastable austenitic steel shafts and dry turned and ground carburized steel shafts in the radial shaft seal ring system}, volume={328–329}, DOI={https://doi.org/10.1016/j.wear.2015.02.004}, journal={Wear}, author={Frölich, D. and Magyar, Balázs and Sauer, B. and Mayer, P. and Kirsch, B. and Aurich, J.C. and Skorupski, R. and Smaga, M. and Beck, T. and Eifler, D.}, year={2015}, pages={123–131} }' chicago: 'Frölich, D., Balázs Magyar, B. Sauer, P. Mayer, B. Kirsch, J.C. Aurich, R. Skorupski, M. Smaga, T. Beck, and D. Eifler. “Investigation of Wear Resistance of Dry and Cryogenic Turned Metastable Austenitic Steel Shafts and Dry Turned and Ground Carburized Steel Shafts in the Radial Shaft Seal Ring System.” Wear 328–329 (2015): 123–31. https://doi.org/10.1016/j.wear.2015.02.004.' ieee: 'D. Frölich et al., “Investigation of wear resistance of dry and cryogenic turned metastable austenitic steel shafts and dry turned and ground carburized steel shafts in the radial shaft seal ring system,” Wear, vol. 328–329, pp. 123–131, 2015, doi: https://doi.org/10.1016/j.wear.2015.02.004.' mla: Frölich, D., et al. “Investigation of Wear Resistance of Dry and Cryogenic Turned Metastable Austenitic Steel Shafts and Dry Turned and Ground Carburized Steel Shafts in the Radial Shaft Seal Ring System.” Wear, vol. 328–329, 2015, pp. 123–31, doi:https://doi.org/10.1016/j.wear.2015.02.004. short: D. Frölich, B. Magyar, B. Sauer, P. Mayer, B. Kirsch, J.C. Aurich, R. Skorupski, M. Smaga, T. Beck, D. Eifler, Wear 328–329 (2015) 123–131. date_created: 2022-12-15T10:17:23Z date_updated: 2022-12-15T10:18:54Z department: - _id: '146' doi: https://doi.org/10.1016/j.wear.2015.02.004 extern: '1' keyword: - Radial shaft seal ring - Shaft surface - Cryogenic turning - Metastable austenitic steel - Deformation-induced martensite formation language: - iso: eng page: 123-131 publication: Wear publication_identifier: issn: - 0043-1648 status: public title: Investigation of wear resistance of dry and cryogenic turned metastable austenitic steel shafts and dry turned and ground carburized steel shafts in the radial shaft seal ring system type: journal_article user_id: '38077' volume: 328-329 year: '2015' ...