Forging of steel encased titanium workpieces

• Applicant: Professor Dr.-Ing. Bernd-Arno Behrens
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 461918196

The proposed research project focuses on the development and the investigation of a new strategy for error-free forming of titanium components with complex geometries under pressure superposition. For this purpose, the blanks will be encapsulated in a steel case and subsequently formed together. A temperature gradient will be induced in the steel casing which arises due to the contact with the forming tools and the environment. At the same time, it will serve as a protective layer against oxidation and adhesion of the workpiece. Utilising this method, an isothermal process control is not needed which allows for the implementation of a flawless titanium forming process. By application of a steel capsule, an improvement of the titanium forming behaviour in the periphery regions is expected, which has a positive impact on the resulting microstructure and thus on the final product properties. The steel layer will be removed during the subsequent post-processing, so that the proportion of difficult-to-recycle titan cutting chips can be minimized. In addition, an increasing formability is expected due to the counter-pressure of steel case in terms of hydrostatic forming.In the framework of this research project, different manufacturing processes of encapsulated workpieces will be considered (spark plasma sintering, friction welding and hot isostatic pressing) to investigate their influence on the workpiece formability dependent on different process parameters. The forming process design will be accompanied by numerical process modelling using FEM, where the optimal parameters for the workpiece geometry and forming temperature will be selected. In the following, the experimental forming tests will be performed in order to define the process limits of the new method based on the resulting component quality.

• DFG Programme: Research Grants