Investigations of magnetostatic fields related to grain boundaries in silicon steel sheets

Abstract

The origin and peculiarities of the spatial distribution of the magnetostatic fields m near the planar grain boundaries (GB) oriented perpendicular to the rolling direction (RD) in grain-oriented silicon steel (GOSS) sheets, which are magnetized along the RD to induction above 1.0 T, are investigated. It was found experimentally that there are perturbations of the net magnetization in grains near the planar GB even at inductions close to saturation Bs. Such perturbations exclude ruptures of the net magnetization normal component Mn and the appearance of magnetic charges (m = µ0 Mn = 0) on the GB surfaces. The calculation of the field m components related to the planar GB was carried out with our assumptions that net magnetization inhomogeneities (the volume magnetic charges m = -µ0 div ) in grains are the sources of this field. The results of the computation are in good agreement with the results of the field m component measurements for the samples of GOSS. Some regularities of magnetic interaction between neighbouring grains in GOSS sheets are discussed.