Determination of shot peening effect on fatigue behavior of AISI 4140 steel by non-destructive measurement of surface residual stresses

Thesis Type: Post Graduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Turkey

Approval Date: 2018




The fatigue performance of aircraft parts can be improved by inducing compressive residual stresses in the near-surface zone by shot-peening. The depth profile and the magnitude of residual stresses depend on the shot peening parameters. Aircraft industry requires an easy and rapid non-destructive method for determination of residual stress state to verify the achievement of the desired results of shot-peening. This study aims to determine nondestructively the residual stresses at the surface by the Magnetic Barkhausen Noise (MBN) method, and also, to investigate the effect of the shot peening severity on the fatigue life of AISI 4140 steel. By this way, it might be possible to correlate the MBN measurement results with fatigue life and to verify nondestructively the success of shot-peening process to achieve the desired fatigue life.