Forming and joining of semitubular self-piercing rivets made of high strength steel with adapted mechanical properties and numerical analysis of the process chain

• Applicants: Professorin Dr.-Ing. Marion Merklein; Professor Dr.-Ing. Gerson Meschut
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: from 2017 to 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 328853593

• Final Report Year: 2024

Final Report Abstract

In view of climate action, mechanical joining processes such as semi-tubular self-piercing riveting are of particular relevance for production technology, as they enable lightweight design. However, the production of auxiliary elements such as rivets is time-consuming, costly and energy-intensive due to the required heat treatment and coating processes. In order to contribute to the transformation towards sustainable production processes, as part of the project, a new approach for the process chain consisting of forming and joining was researched. By using high strain hardening, stainless rivet materials, the heat treatment and coating of the rivets can be omitted. However, challenges for forming and joining exist in this context. During forming, a high tool load arises, which is why suitable forming concepts are required to ensure manufacturability. As the demanding joining of high-strength steel is indispensable for lightweight design, the joinability must be ensured. The aim of the project was therefore to develop a fundamental understanding of the forming and joining of selfpiercing rivets made of high strain hardening, stainless materials. Experimental and numerical analyses were used to identify cause-and-effect relationships, which represented the basis for the successful realisation of the new approach. As the heat treatment of the rivets can be omitted, the gradation of the mechanical properties resulting from forming is retained. This effect can be utilised by adjusting the properties according to the requirements of joining. Thus, the basis for the production of customised rivets was created.

Publications

• Heating effect on the forming behaviour of high nitrogen steel in bulk forming. AIP Conference Proceedings, 2113, 160004. AIP Publishing.
  Kuball, Clara-Maria & Merklein, Marion
  
• Influence of the process temperature on the tribological behaviour during bulk forming of high nitrogen steel. In: Faculdade de Engenharia da Universidade do Porto (Hrsg.) AJP 2019 – 1st International Conference on Advanced Joining Processes, 24.-25. Oktober 2019, Ponta Delgada, Azoren, Portugal. Quântica Editora, Lda., 2019, S. 29
  Kuball, C.-M.; Jung, R.; Uhe, B.; Meschut, G. & Merklein, M.
  
• Improvement of a rivet geometry for the self-piercing riveting of high-strength steel and multi-material joints. Production Engineering, 14(4), 417-423.
  Uhe, Benedikt; Kuball, Clara-Maria; Merklein, Marion & Meschut, Gerson
  
• Influence of the process temperature on the forming behaviour and the friction during bulk forming of high nitrogen steel. Journal of Advanced Joining Processes, 1, 100023.
  Kuball, C.-M.; Jung, R.; Uhe, B.; Meschut, G. & Merklein, M.
  
• Process design for the forming of semi-tubular self-piercing rivets made of high nitrogen steel. Procedia Manufacturing, 50, 280-285.
  Kuball, Clara-Maria; Uhe, Benedikt; Meschut, Gerson & Merklein, Marion
  
• Influence of the Rivet Coating on the Friction during Self-Piercing Riveting. Key Engineering Materials, 883, 11-18.
  Uhe, Benedikt; Kuball, Clara Maria; Merklein, Marion & Meschut, Gerson
  
• Selective application of different forming temperatures for individual process stages in a rivet manufacturing process with high nitrogen steel. In: Faculdade de Engenharia da Universidade do Porto (Hrsg.) AJP 2021 – 2nd International Conference on Advanced Joining Processes, 21.-22. Oktober 2021, Sintra, Portugal. Quântica Editora, Lda., 2021, S. 29
  Kuball, C.-M.; Uhe, B.; Meschut, G. & Merklein, M.
  
• Self-Piercing Riveting Using Rivets Made of Stainless Steel with High Strain Hardening. The Minerals, Metals & Materials Series, 1495-1506. Springer International Publishing.
  Uhe, Benedikt; Kuball, Clara-Maria; Merklein, Marion & Meschut, Gerson
  
• Strength of self-piercing riveted Joints with conventional Rivets and Rivets made of High Nitrogen Steel. ESAFORM 2021.
  Uhe, Benedikt; Kuball, Clara-Maria; Merklein, Marion & Meschut, Gerson
  
• Process-adapted temperature application within a two-stage rivet forming process for high nitrogen steel. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 236(6), 1285–1301.
  Kuball, C.-M.; Uhe, B.; Meschut, G. & Merklein, M.
  
• Approach for a sustainable process chain in manufacturing of fasteners for mechanical joining. Sheet Metal 2023, 25, 397–404.
  Uhe, B.
  
• Controlled Rivet Deformation During Self-piercing Riveting Through a Tailored Strength Distribution Within the Rivet Material. Lecture Notes in Mechanical Engineering, 64-71. Springer Nature Switzerland.
  Uhe, Benedikt; Kuball, Clara-Maria; Merklein, Marion & Meschut, Gerson
  
• Increased Sustainability in Fastener Production with the Example of Self-Piercing Rivets. Journal of Manufacturing and Materials Processing, 7(6), 193.
  Uhe, Benedikt; Kuball, Clara-Maria; Merklein, Marion & Meschut, Gerson
  
• Mechanical joining of high-strength multi-material systems − trends and innovations. Mechanics & Industry, 24, 16.
  Merklein, Marion; Jäckisch, Manuel; Kuball, Clara-Maria; Römisch, David; Wiesenmayer, Sebastian & Wituschek, Simon
  
• Corrosion behaviour of self-piercing riveted joints with uncoated rivets in high nitrogen steel. Production Engineering, 18(3-4), 475-482.
  Uhe, Benedikt; Kuball, Clara-Maria; Merklein, Marion & Meschut, Gerson
  
• Cross-process chain influence of process variations in self-piercing riveting with regard to semi-finished product dimensions. Journal of Advanced Joining Processes, 9, 100227.
  Kuball, Clara-Maria; Uhe, Benedikt; Meschut, Gerson & Merklein, Marion
  
• Grundlegende Untersuchungen zur umformtechnischen Herstellung von Halbhohlstanznieten aus hochverfestigenden Werkstoffen. Dissertation, FAU Erlangen-Nürnberg, 2024. ISBN: 978-3-96147-717- 3
  Kuball, C.-M.
  
• Ressourcenschonende Herstellung von Halbhohlstanznieten durch Prozesskettenverkürzung. Dissertation, Universität Paderborn, 2024. ISBN: 978-3-8440-9601-9
  Uhe, B.
  
• Umformung von Bauteilen aus hochverfestigenden Werkstoffen zur Vermeidung von Wärmebehandlungen – Potentiale und Herausforderungen. Werkstoffe in der Fertigung 5, S. 26–29. ISBN: 0939-2629/B 25800
  Kuball, C.-M.; Uhe, B.; Meschut, G. & Merklein, M.