Tool aspects for high temperature level gas forming: Presentation held at 9th International Conference on Tube Hydroforming, TUBEHYDRO 2019, November 18-21, 2019, Kaohsiung, Taiwan

Hydroforming at room temperature is a well-established process that is used to produce complex, tubular component geometries accordingly. However, the past has shown that multi-stage process chains (pre-and final-form operations), comparatively long process times and complex plant technology often lead to high production costs. This means that the technology is mainly reserved for highly complex components that have to meet particularly high quality standards. By using gaseous forming media instead of the water-based emulsion, the limitation of having to perform the forming process at room temperature is no longer necessary. For many typical materials for which hydroforming is today in series application, the forming properties can be significantly improved with the help of the process parameter temperature, which, on the one hand, leads to the loss of complex pre-form operations, on the other hand to a further increase in the safely manufacturable component complexity. Process, material and last but not least the necessary final component properties require different scenarios of heat treatment. These tempering concepts are particularly challenging for the forming tools. For this purpose, processes with passive temperature guidance are distinguished, in which a pre-heated component is inserted into an actively cooled tool or active processes in which the component is transferred into a heated tool. Especially in the latter case, the requirements for the forming tool are further increased by spatially and temporally variable temperature fields, which have to be implemented reproducibly. In addition to the heating and cooling technology used in the tool, the tool material and a corresponding tool coating play a crucial role in successful process management, consistent quality and a long tool lifetime. The associated aspects of high temperature level gas forming tool design are described in the following paper