Dynamic magnetostriction and mechanical strain in oriented 3% silicon-iron sheet subject to combined longitudinal and transverse stresses

Measurements have been made of dynamic magnetostriction in 3%-silicon oriented magnetic sheet steel (Goss textured) under combined longitudinal and transverse stresses between 600Ibf/in2 compression and 600Ibf/in2 tension longitudinally, and between 600Ibf/in2 compression and 400Ibf/in2 tension transversely. It was found that the results obtained on many different samples could all be reasonably represented by a single master curve of magnetostriction against longitudinal stress with appropriate zero shift for each sample. This zero shift was then used as a figure of merit for the stress sensitivity of each material. Measurements were also made of static strain against mechanical stress. The stress/strain curves show nonlinearity due to domain movements. The shape of these curves was used quantitatively to support a theoretical explanation of the relations between the effects of longitudinal and transverse stresses on dynamic magnetostriction. The curves may also be significant for such purposes as calculation of core resonant frequencies. Double-phosphate-coated catenary-annealed steel was found to be less stress-sensitive than normal single-phosphate-coated roller-hearth-annealed sheet, and it was shown that the second phosphate coating was responsible for much of the improvement.