Experimental Investigation of Shot Peening on Case Hardened SS2506 Gear Steel

Shot peening is a manufacturing process commonly used to increase fatigue life in components for the automotive and aircraft industry. In this paper the effect of shot peening is described for a case hardened gear steel. For gears there are three main factors from shot peening that influence fatigue life: residual stresses, microstructure and surface roughness. The paper describes an experimental series where these parameters were measured for common industrial shot peening settings. The aim was to show how several different measurement techniques and results correspond to each other for certain shot peening parameters. The aim was also to gather experimental results that can be used for verification of shot peening simulations. To simplify measurements and decrease variation, flat steel plates were used as targets. Residual stress, full width at half maximum (FWHM), retained austenite, surface roughness/topology, hardness and Barkhausen noise were measured and related to microstructural changes. The mean indentation diameter was measured for individual shots at low coverage of each intensity which was used to determine the average velocity of the media. The mean diameter and hardness of the shot peening media was also determined.