State of residual stress induced by cyclic rolling contact loading

The accumulation of plastic microdeformation during cyclic stressing under rolling contact loading conditions results in a complex state of residual stress in the subsurface volume of deep groove ball bearing inner rings. The three-dimensional state of residual stress was analysed experimentally for the first time, employing a combination of methods based on X-ray diffraction. The residual stress field exhibited components of internal stress which were maximal close to the depth at which stresses induced by the external load were at a maximum. From this position the values of the principal components of residual stress decreased with steep gradients towards the surface and to a larger depth. Compressive residual stresses existed in the circumferential and axial directions while in the surface normal direction a tensile residual stress was present. The trends observed by the diffraction analysis were in qualitative agreement with measurements of ring distortion performed upon sectioning.