Some observations on the magnetic anisotropy of non-oriented 3% Si steels

The standard method of assessment of the degree of anisotropy in non-oriented electrotechnical silicon steels destined for use in rotating machines has been to measure total power loss typically at 1.5 T, 50 Hz in samples cut longitudinally and transversely with respect to the rolling direction of the sheet. The validity of this method is based on the assumption that the change in total power loss is such that as one progresses from the longitudinal to the transverse direction, the minimum and maximum values respectively occur in these directions. Recent work has thrown considerable doubt on this assumption. It has been shown that differing production methods do not produce such a change between longitudinal and transverse results; that the maximum and minimum values may not occur at these positions; and that changes in the rolling/annealing regimes of production produce loss/ angle to rolling direction relationships of widely differing form.