Residual stress evolution during the manufacturing of an aircraft component

This paper proposes a comprehensive analysis of the evolution of the surface residual stress state over the manufacturing stages of generic forged aircraft components. This has been achieved through an experimental procedure, involving forging of the generic component preforms, heat treatments, and machining operations on Computer Numerical Control milling and lathe centers. Surface residual stresses were measured using X-ray diffraction technique. The results showed a high scatter of surface residual stress measured in the same zone although the machining was done by the same cutting tool and under the same machining conditions. This suggests that the residual stress measured at a specific zone is significantly sensitive to previous and further major material removal such as rough pocketing the components have underwent. Moreover, it was found that the quenching and aging heat treatment drastically modify, not only the machining induced-residual stress state, but also the physical surface characteristics as demonstrated by the shear to normal residual stress ratio and the full width at half maximum of the X-ray diffraction peaks. Conclusively, the findings of this work help both researchers and manufacturers to better understand the challenges related to the design and the manufacturing of structural aircraft components made from forgings.