Plastic Deformation and X-Ray Stress Measurement of Grain Oriented Silicon Steel

Abstract

For the purpose of stress measurements in a particular grain of metallic materials or in a few grains of grain oriented materials, the strain conditions in individual grains were analyzed in terms of crystallography. The analytical results were examined experimentally by X-ray stress measurements which were carried out on the grain oriented silicon steel sheets being in the state of uniaxial plastic deformation.
In the case that the silicon steel sheets were stressed in parallel to the rolling direction, it was found experimentally that the stress in each grain could be regarded as constant and nearly equal to the applied stress. This tendency was also recognized in the analytical results of the stress in grains calculated on the assumptions of the Sachs' and Taylor's models, and the stress in both models agreed with those measured by the X-rays.
In the case that the tensile axis was selected coincident with the direction perpendicular to the rolling one in the plane of the sheet, the measured values indicated a large amount of scattering due to the dispersion of the stress in each grain. Although the results from the Taylor's model showed a similar tendency, the amount of scattering from this model was larger than the measured one. On the other hand, no scattering was recognized in the results from the Sachs' model. In this case, the stress of the specimen in bulk could be obtained from the averaged values of the lattice strain over several times of measurement.