Influence of surface coating on transverse magnetostriction in silicon iron

Samples of grain-oriented 3¿% silicon iron have been tested for magnetostriction when magnetised at 90° to the rolling direction, and the effects of tensile stress have been observed. These tests were performed on coated and decoated samples, and included the effect of magnetic annealing. From variations in magnetostriction, an assessment has been made of the internal stresses in the materials, and a stress equivalent for magnetic annealing has been deduced. The influence of the coating has been considered in the light of the various stresses which it sets up, both on the magnetostriction and magnetic-annealing processes. A comparison has been made of the differing contributions of the coating to the performance of conventional and highly oriented silicon iron.