Extension of the forming limits in internal high-pressure hot forming through isothermal process conditions

In the isothermal high-temperature pneumoforming (IHTP) process, direct resistance heating of tubes is maintained during the forming process, thus achieving extended forming limits compared to the conventional process route of internal high-pressure hot forming. This project focuses on expanding geometric flexibility through the use of active die elements. Furthermore, the aim is to quantify the geometry-specific temperature inhomogeneities. In doing so, both inhomogeneous heating rates resulting from the current density distribution and interactions between the workpiece and the tool are taken into account and are correlated with the resulting formability. Material-specific research objectives for ferritic stainless steel include characterizing the thermal softening behavior and the influence of this behavior on the internal pressure required for forming. For hardenable steel, the potential of process-integrated heat treatment through sufficiently high cooling rates after isothermal forming will be investigated.

Kamaliev, M.; Flesch, J.; Grodotzki, J.; Tekkaya, A.E., 2023

Numerical and experimental analysis of the isothermal high

temperature pneumoforming process. International Journal of Material Forming 16 (44).
https://doi.org/10.1007/s12289-023-01767-y