X-ray microdiffraction for the analysis of bearing operation conditions

The use of residual stress measurements for the analysis of the performance of rolling bearings has become a common tool in the bearing industry. The effects of rolling contact fatigue on the development of residual stresses in the loaded zones of a bearing has been investigated in much detail. In this paper, the developments of the use of X-ray microdiffraction for residual stress measurements in bearings will be described. In microdiffraction, measurements are performed with very small irradiated spots. Advances in X-ray diffraction technology have made it possible to determine the residual stresses in loaded components in small areas with a high level of detail. The method and its consequences for bearing analysis is discussed in this paper. Using the method, much more information on the exact operation conditions of a bearing can be extracted from the components compared to conventional X-ray diffraction methods. Residual stress measurements using microdiffraction have been successfully applied in an application analysis case, where the measurements were used to show the residual stress development in the bearing surface during operation. In such a case, microdiffraction could also be used to investigate local bearing life limiting features, such as surface damages.