Mechanism-driven fine blanking of high manganese steel for target-oriented setting of material and sheared part properties (Fine blanking induced plasticity)

• Applicants: Professor Dr.-Ing. Thomas Bergs; Professor Dr.-Ing. Ulrich Krupp
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 548386476

High manganese steels (HMnS) are characterized by a high strain hardening of the sheared surface zone during fine blanking as a result of the deformation mechanisms TWinning Induced Plasticity (TWIP) and TRansformation Induced Plasticity (TRIP). The high strain hardening driven by the deformation mechanisms offers potential for increased wear and fatigue strength of tribologically stressed fine blanked surfaces. The activation of various deformation mechanisms during fine blanking of HMnS and their interactions as a result of the variables acting in the shear zone lead to an influence on the sheared surface hardening as well as quality. These interactions are also influenced by the alloy design and the stacking fault energy (SFE) of HMnS. The interactions between HMnS alloy design, fine blanking process as well as deformation mechanisms and their influence on material and sheared part properties have not been researched so far. The objective of the research project is a knowledge-based explanation of the cause-effect relationships between the alloy design of HMnS and the process design during fine blanking as well as their effects on the sheared part properties regarding deformation mechanism-related hardening, quality and basic strength. For this purpose, the influence of the SFE as well as the fine blanking process parameters on the activation of the deformation mechanisms in the shear zone is to be analyzed regarding the Fe-Mn-C-Al-Si alloy system. This is done on the one hand by means of experimental investigations with regard to the process parameter influence on the sheared part properties during fine blanking of TWIP steel 1.7401. On the other hand, two alloys from the Fe-Mn-C-Al-Si system with differing SFE are designed, manufactured and subjected to a mechanical-technological analysis regarding the material properties. On this basis, an interaction analysis is carried out on both the process and material sides using numerical simulations based on the finite element method. By coupling numerically determined shear zone variables during fine blanking with a numerical material model for alloys of the Fe-Mn-C-Al-Si system, a mechanism-based strain hardening analysis is realized. The numerical material model is finally extended and analyzed in terms of the influence of microalloying elements on the strength properties. In a final synthesis of the results, an explanatory model is developed for the cause-effect relationships between the alloy design of HMnS, the process parameters during fine blanking as well as the mechanism-driven hardening and its effects on the sheared part and material properties. Based on the obtained findings, alloys with high basic strength are derived from the Fe-Mn-C-Al-Si system for a target-oriented activation of the deformation mechanisms during fine blanking.

• DFG Programme: Research Grants