Characterization of residual stresses in turbine discs by neutron and high-energy X-ray diffraction and comparison to finite element modeling

Abstract

Knowledge of the evolution of residual stresses developing during fabrication of industrial components is steadily gaining importance. In this paper, the prevailing residual stresses in hot-forged, water-quenched turbine discs made of the nickel-based superalloy IN718 have been studied by neutron diffraction. Simultaneously, independent simulations using a finite element model (FE) have been performed. For a deeper examination of the studied component, the material and the simulation, a smaller model plate of the same alloy was measured as well. Furthermore, an in situ tensile test, employing synchrotron radiation, has been carried out to study the deformation behavior of the different reflections. The results show that the simulation gives a good description of the residual stress distribution in the turbine disc while the agreement is less satisfactory for the smaller plate. The tensile tests confirm that the (3 1 1) reflection gives a good measure for the macrostress in the studied material.