Granular media-based tube press hardening

• Applicants: Dr. Philip Born; Professor Dr. Matthias Sperl; Professor Dr.-Ing. A. Erman Tekkaya
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: from 2014 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 266685077

Press hardening of boron micro-alloyed steel sheets 22MnB5 is a well-established manufacturing process for the production of ultra-high-strength-parts, which are used in modern car bodies, in order to fulfill the increasing requirements on crashworthiness and lightweight design. However, for some vehicle components, such as sub frame, crash box, axle components, not only strength but also stiffness is required. Press hardening of closed profiles is a prime candidate to reduce weight and increase safety of vehicle constructions, combining the advantages of press hardening of sheet components and of hydroforming of closed profiles to produce lightweight materials with high strength and high stiffness.The high pressures and high temperatures required for the hot forming process are not supported by present forming media. The application of granular media not only fulfill these requirements but also requires nearly no changes to current tube hydroforming equipment. It is the main objective of the proposed project to provide the technological and scientific foundation for the combination of press hardening and media-based tube forming using granular media.The investigations aim at identifying the intrinsic limitations posed by the use of granular media, developing strategies to improve the forming ability of granular material as working media and providing technologies for press hardening in media-based tube forming.Investigation of particle interactions, granular processing and structure formation from physical aspect will provide the granular media solution for the forming process. The effect of the granular media solution will be tested and identified by characterization tests as well as force transmission and distribution investigation. These fundamental works can provide knowledge on investigation of the process window to guide tube forming experiments. Process window consisting of knowledge from granular media aspect to process parameters like loading-feeding paths, tool geometries, temperature will be demonstrated in a complex geometry tube forming experiment.

• DFG Programme: Research Grants