Simultaneous observation of grain structure and orientation in oriented silicon steel

To determine the origin of grains having spurious orientations in otherwise well-oriented silicon steel, it is sometimes desirable to observe simultaneously the shape and distribution of grains having specific orientations in a large sample of a coarse-grained polycrystalline sheet. A technique related to optical goniometry and an optical device for making the desired observations are described in detail. Photographic records of such observations are presented and explained. This device and rapid technique can be used to depict the preferred orientation in large (and therefore, statistically significant) samples of coarse-grained polycrystalline material. Present methods, which involve the stereographic plotting of poles of many grains, whose orientations have been determined by as many Laue interpretations, could be supplanted. Resulting photographic records could be more widely and intuitively understood, particularly by less technically skilled observers, since interpretation does not require familiarity with pole figures or stereographic projection.