X-Ray Diffraction is a common NDE technique that can be used to determine the levels of residual stress in the near surface layers of a component. X-rays probe a very thin surface layer of the material (typically tens of microns), and it is from this layer that the near surface residual stress is measured. The sample need to be polycrystalline materials.

There is currently a European standard being formulated. There is an NPL Good Practice Guide which is used internally as a measurement procedure.