Toward Holistic Digital Material Description During Press-Hardening

Abstract

AbstractPress hardening of manganese-boron steels is one of the most widely used production processes for high-strength automotive components. The low residual formability of these parts is a decisive disadvantage. The low formability originates from a strong, but brittle martensitic microstructure transformed during quenching in the press-hardening tool. In contrast, medium manganese steels (MMnS) contain high fractions of ductile retained austenite improving press-hardened parts toward promising candidates for crash-relevant car body components. Disadvantages include a more complex alloy design, a highly sensitive production process, and more demanding requirements on the tool due to higher strength during press-hardening.A detailed description of the entire production process along the process chain including the material and the press-hardening tool is important for tailoring the properties. Combined information is required to enable a precise control of the production process and its influences on the final properties of the part. Maximum economic use of the material is achieved by digitally describing MMnS as well as the tool along the entire process chain (casting, forging, hot rolling, cold rolling, galvanizing and press hardening including Q&P). To link the process steps and to describe the changes of the material, a new material database structure (idCarl) was developed. All production parameters are recorded and processed as a digital material twin. Ultimately, deviations occurring during production process can be deduced from in-line data analysis and counteracted. These can then be counteracted by adapted process control and the product can be brought back into the required parameter field of properties. Clear identification of the component and the used material allows conclusions about steps responsible for errors in the production process that become apparent during use.