Forged parts classified as class 1 parts in the field of aerospace own high requirements in safety and quality and must not fail prematurely. The manufacturing of such highly critical parts needs a production-strategy with maximized process-stability and high focus on quality. Turbine discs, made of IN 718, are class 1 parts. The mechanical properties of such parts have a certain sensibility to different production parameters like the effective strain. Thus it is essential, that the deformation in manufacturing is the same as in the original process design. Due to the high temperature strength of IN 718 and the geometry of the focused part, high forces are required to forge the billet into its turbine disc shape. Therefore huge forging equipment with high accuracy are used to produce this kind of parts. Due to the high forces the forging press deforms itself elastically, which has a direct influence on the plastic deformation of the forging part. As this fact cannot be eliminated it is necessary to gain knowledge about the elastic behaviour of the press and its influence on the amount of plastic deformation in the part. In this thesis the effect of the elastic press response during forging on the degree deformation of turbine discs is investigated. Thus the mounting condition of forging tools is evaluated by means of Finite-Element Method (FEM). In addition possible sensors for an active measurement of the distance between upper and lower die with higher accuracy should be found. The influence of the forging press elasticity on degree of deformation of the focused part was evaluated using a FE-multiple-body simulation. The examined main tool components are the toolholder, the dieholder and the die itself. The output of the multiple-body simulation presented a very strong inhomogeneous elastic response of the die and a low elastic deformation of the toolholder and the dieholder. Based on the simulation it can be seen that in the center of the die a higher elastic deformation (+ 2mm) occurs than in the edge area. For the measurement of the die-gap the existing sensors of the forging press were evaluated. The result showed the necessity of a more precise system closer to the forging part. Hence commercially available measuring systems were compared against each other and the best ones were tested in operation. The harsh environment with its high temperatures (more than 300°C) and heavy polluting effect of the lubrication prohibit most commercially available sensor options. Even such rugged sensors like inductive and capacitive sensors could not achieve the requirements. Optical measurement systems could not be applied because of the invisibleness of the deformation area due to the overlapping upper toolholder. Only contact based “sensors” showed their usability to measure the die-gap as the already existing and firmly established method with aluminum cubes positioned at the edge of the lower die. After the forming process the squeezed aluminum cubes deliver the die-gap by simply measuring their height. For a repeatable measurement of the die-gap, an automatic positioning system for the aluminum cubes with an also automatic height measuring method is recommended.
|Translated title of the contribution||Multi-body analysis and digitization of the installation condition of forging tools|
|Award date||25 Oct 2019|
|Publication status||Published - 2019|
Bibliographical noteembargoed until 13-09-2024
- Aerospace Turbine Discs
- Process Data