X-ray diffraction is a well-known experimental technique for measuring residual stresses inmetallic materials. If XRD is applied to the fracture surface of a broken part it becomes a fractographicaltechnique, that is to say that it is possible to relate the results of the measures to the loading condition thatlead a component to fail. In this paper, after an introduction about the technique, XRD fractography is appliedto a fatigue failed diesel engine crankshaft. It was possible to determine the load that lead the crankshaftto fail and to evidence some original aspects about the application of this technique to real machineparts
