Load and function-oriented tool design for finish turning of rotationally symmetrical components made out of the nickel-based alloy Inconel 718

• Applicant: Professor Dr.-Ing. Thomas Bergs
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 503700894

Functionality, operational behavior and service life of highly stressed, safety-critical jet engine components, such as turbine disks and blades that are made out of the nickel-based alloy NiCr19Fe19Nb5Mo3 (Inconel 718), are largely determined by the dimensional accuracy and by the properties of the machined surface. Therefore, manufactured turbine components have to meet the highest demands concerning geometric tolerances, residual stresses and microstructure modifications in the machined surface. Numerous scientific studies have shown that the machining induced thermo-mechanical load has a significant influence on the machined surface and fatigue strength of the component. Therefore, there is a great potential for increasing the component's fatigue strength by the tool design and tool behavior during the cutting process. A broad, systematic use of this potential is not yet given in practice. In addition, the process design for the machining of critical components in the aerospace industry is largely based on empirical values. The reason for this is the lack of knowledge of generally applicable statements about the influence of the process parameters on specific rim zone characteristics and the component behavior during turning operation. The aim of this research proposal is to analyze the manufacturing-related influence of turning operations on the rim zone and the fatigue strength of dynamically highly loaded, rotationally symmetrical components, to evaluate them and to derive measures for a load and function-oriented design of the cutting edge for finish machining high-temperature materials. The design of the surface-generating cutting part (secondary cutting edge) is based on the premise of maximizing the service life of the component and the design of the material-removing cutting part (main cutting edge) on the premise of maximizing the tool life. With the help of the process simulation, the designed cutting edge geometries are tested in use. The optimized cutting edge geometries are finally selected on basis of the computed result variables, manufactured and verified in the real machining process.

• DFG Programme: Research Grants