A Method of Stress Measurement from Some Spotty X-Ray Diffraction Rings

Abstract

To measure residual stress in a large construction by X-ray method, it is convenient to use a simple and small apparatus with the photographical system. Generally, these structural steels have a coarse grained structure which provides spotty diffraction ring, thus preventing the accurate measurement of ring radius. To avoid this difficulty, several attempts such as oscillating the film or moving the specimens have been made. But these methods have their own limitation.
In the present paper, a method of determining ring radius from spotty X-ray diffraction rings obtained from a fixed specimen is presented. The method is basically to average the radial distance of each spot from the diffraction ring of the standard substance coated on the specimen surface. An automatic measuring device of these spotty rings is also discussed in the paper.