Analysis of the application potential of roll-clad MnB-Cr steel composites for press hardening

• Applicants: Professor Dr.-Ing. Gerhard Hirt; Professor Dr.-Ing. A. Erman Tekkaya
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Metallurgical, Thermal and Thermomechanical Treatment of Materials
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 444548865

In this project, a new material system is to be developed and improved in terms of its applicability in the direct press hardening process. Instead of the usual hot-dip aluminized sheet blanks, a composite material with a boron-manganese alloy core and outer layers of Cr or Cr-Ni steel is to be produced. Disadvantages of the standard aluminum-silicon coating (AlSi) such as reduced heating rates, extended holding times at elevated temperatures, increased wear and the lack of active corrosion protection are thus eliminated. At the same time, there is now a need for research regarding the production and processing of such composites.At IBF, the focus is on the fundamental physics of composite fabrication. Derived experiments under laboratory conditions and the use of numerical tools serve to provide a basic understanding of composite fabrication. Required temperatures and roll passes, as well as the need for pre- and post-processing, are determined and used to promote the reliable production of composite blanks. In the later part of the project, it is intended to design and produce composites with asymmetrical outer layers, as well as different cover layer materials, which would enable the manufacture of flexible and load-adapted composite blanks.At the IUL, the focus is on the reliable processing of composite materials in the press hardening process. Based on the tribological and mechanical characterization of the individual materials, the boundary conditions for the process are investigated by experimental and numerical studies. The evaluation of the composites under press-hardening conditions provides information on the adequacy of the inter-layer adhesion during hot working as well as under press-hardened condition. The design of a demonstrator component, in which the influences of the electrical and conventional heating methods on the process and the product properties can be examined in a targeted manner, as well as the determination of component properties, conclude the planned work in the first funding period.Synergies between the research centers emerge in the determination of the plasto-mechanical properties, as well as the numerical and experimental determination of the time-temperature-transformation behavior. Particularly, due to the differing behavior of the two composite-partners, time-delayed and internal-stress influenced microstructural changes are to be expected.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Christian Löbbe