Analysis of Vibratory Finishing Effect on the Fatigue Behavior of Shot Peened Notched 40NiCrMo7 Steel Notched Specimens

Author:  I. Fernandez-Pariente a, S. Bagherifard b, M. Bandini c, M. Guagliano
Source:  ICSP-13
Doc ID:  2017125
Year of Publication:  2017
Abstract:  
Abstract: In this paper the influence of surface roughness on fatigue behavior of notched specimens has been studied. Series of notched specimens of 40NiCrMo7 quenched and tempered steel, shot peened with different parameters followed by a vibratory finishing process, were subjected to room temperature rotating bending fatigue tests in order to study the influence of roughness on fatigue behavior. The effect of all treatments were characterized by means of roughness measurements, X-ray diffraction measurements and scanning electron microscopy (SEM) analysis. The results show that vibratory finishing affects the surface condition of shot peened specimens in two ways: decreasing surface roughness and removing a very thin layer of material with compressive residual stresses. This effects influence fatigue behavior, and confirm that high surface roughness does not necessarily lead to reduced fatigue strength.