In the present paper, to provide information on the stress measurement in coarse grained materials by X-ray micro-beam diffraction technique using a crystal oscillation method, the authors first examined experimentaly and theoretically the relation between the sizes of X-ray beam and crystal to obtain the particular diffraction ring in the case of use of crystal oscillation method. The specimen attachment of X-ray camera used in this experiment can be oscillated automatically around a horizontal and vertical axes with high accuracy centering around an illuminated position on the specimen surface.
Accordingly it is possible to increase the number of the diffraction spots without changing the area and position of the specimen illuminated. Experiments were carried out for three kinds of annealed low careon steel with grain sizes of about 15, 30 and 50μ in diameter, and with X-ray beam collimated by pinhole slits of 0.12, 0.30 and 1.00 mm in diameter, using CrKα characteristic X-rays. On the other hand, a theoretical analysis was carried out according to the X-ray diffraction theory which have been proposed by P. B. Hirsch et al. As the conclusion, it is found that the crystal oscillation method is extremely
useful for X-ray stress measurement of coarse grained materials. Moreover, the conditions of the crystal oscillating operation were clarified theoretically for any pair of the sizes of X-ray beam and crystal.