Shot Peening for Surface Topography Optimization to Avoid Micro Pitting

Author:  C. Peyrac, D. Ghribi, F. Lefebvre, J. Samuel
Source:  ICSP-13
Doc ID:  2017049
Year of Publication:  2017
Abstract:  
Abstract: Mechanical components suchas gears or bearings are highly affected by contact fatigue phenomenon. It is well known that the micro pitting mechanism is responsible for components fracture/failure by contact fatigue, and there are a lot of details in the literature describing its morphology, apparition, etc. [1-3]. Despite the trivial predominant impact of the surface roughness on micro pitting apparition, there are several attempts in literature to establish a relationship between surface roughness and micro pitting. In this paper, it is shown that an appropriate/controlled shot peening, could reduce the micro pitting phenomenon. A specific image analysis methodology applied to quantify the micro pitting, is described. This methodology allows the comparison between the reference and the shot peened specimen by means of interrupted tests. Relationship between surface topography and micro pitting is also established using surface characteristics (Rku or Rsk) and functional parameters (specific film thickness ( and sliding ratios). EBSD analyses have pointed out surface accommodation by plastic deformation at the beginning of contact fatigue tests.