from the conferences organized by TANGER Ltd.
The QP process enables to achieve excellent combination of strength and ductility in low alloyed steels. However, the process itself is rather difficult to implement into a serial production of high strength parts as it is demanding precisely controlled temperature cycle for each part. Hot metal gas forming (HMGF) is a technology with potential to provide QP thermal treatment within tight constraints. Moreover, the tool for HMGF can be segmented from materials with different thermal conductivity. This results in different cooling rates, different microstructures and ultimately in different mechanical properties in different areas of the part which can be favourable for the for lightweight design. Three steels have been casted as 500 kg test batches and dilatometer analysis were performed to map the austenite decomposition. Steels 42SiCr, 38SiCr and 32MnB5 were subjected to the simulation of HMGF regime with two different cooling rates simulating the HMGF tool composed of two different materials. SICr steels proved to be able to preserve significant amount of austenite in the microstructure, up to 16 vol.%.
Keywords: quenching and partitioning, hot metal gas forming, retained austenite, high strength steel© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.