Life Enhancement of Aero Engine Components by Shot Peening: Opportunities and Risks

Author:  Gerhard W. Konig, MTU Aero Engines, Munich, German
Source:  Conf Proc: ICSP-8 Sept. 16-20, 2002 Garmisch-Partenkirchen, Germany
Doc ID:  2002003
Year of Publication:  2002
Abstract:  
Abstract In service, aero engine parts are subject to high temperatures and extreme cyclic loads. As a consequence, the initiation and propagation of surface fatigue cracks is life-limiting for many components. The application of surface treatments, such as shot peening, can cause a shift of the crack initiation site from surface to subsurface and concomitantly, a significant increase in the cyclic life. However, in practice, the actual improvement achieved by shot peening is sometimes found to be less than expected. One reason is that residual stresses produced by shot peening are not stable against high temperatures and non-elastic deformation induced by service loads. Another reason is that defects (intrinsic defects of the material, surface defects caused by handling as well as surface damage caused by peening itself) may also reduce the benefit of shot peening. The following paper discusses the possibilities to exploit the benefits of shot peening for life enhancement of aero engine components and the requirements that must be fulfilled to take full advantage of shot peening.