Thermal assisted incremental forming of tubes and sheets with process-integrated heat generation
Funding organisation:
Deutsche Forschungsgemeinschaft, Sonderforschungsbereich Transregio 30
Description:
The motivation of this project is to enhance the forming limits of metal spinning processes by integrating local thermo-mechanical sub-processes. The process-integrated and locally adapted heat generation by friction substitutes external heat sources as torches and burner systems and enables the production of innovative products with graded property profiles, needing less machinery effort and energy. This allows the manufacture of hollow metal workpieces with task-adapted, locally graded properties which were not or only hardly producible so far. The so-called `friction-spinning process provides the potential to manufacture such products by combining metal spinning and friction welding.
Special friction and forming tools generate the shape and gradation by simple trajectories which will be enhanced in the further course of the project. Furthermore, based on the specific statistical methods which have been developed within the scope of the first period of this project, focus is put on the identification and choice of process parameters and on gaining better fundamental process insight. In the context of the process-oriented technological research the findings concerning hardness gradation and distribution should transferred from forming tube ends to the contour processing. Moreover, promising gradation options regarding (micro-) structural setup, insertion of residual stress states, and, in case of steel as workpiece material, the setting of specific phase distribution options need to be investigated. In addition to the generation of various types of gradation the setting of defined gradation transitions with regard to dimension and sharpness will be an important aspect of the ongoing research activities. At first, focus will be put on conventional high-strength and higher-strength 5000, 6000, and 7000 series aluminum alloys. In the course of the project steel materials such as S235JRG2 or 20MnB5 will become object of the research activities. Apart from various research approaches regarding the generation of different gradations, the development of new tools and tool systems for shaping is an essential part of this subproject. Promising results of manufacturing single geometric elements are shown in figure A7-2. Based on these results, composite and more complex geometries may be producible after a step-by- step process of development.
