Abstract
Failures in operation sometimes result from defects in engineering structures. The purpose of failure analysis is to determine the cause of failure. In order to prevent the failure accidents, it is necessary to make a quantitative analysis on the fracture surface.
In the present paper the X-ray fractographic technique was applied to the examples of actual fracture of machine parts. The distribution of the residual stress beneath the fracture surface was measured with the X-ray diffraction technique. The plastic zone size was determined from the distribution of the residual stress and was used to estimate the actual fracture stress.
