Effect of electrically insulating coatings on anisotropy of magnetic characteristics of textured transformer steels

Effect of electrically insulating coatings on anisotropic features of magne tic properties of various sorts of cold-rolled anisotropic transformer stee l manufactured by VIZ-Stal (Verkh-Isetsk Metal Works) has been investigated using a modified magnetic-powder technique for studying scattered magnetic fields, which enables observation of domain structures in large-grain stee ls below insulating coatings, and the physical causes of this effect have b een elucidated. Feasibility of using the technique of visualization of magn etic domains in a transformer steel beneath an electrically insulating laye r for testing indirectly the material quality has been analyzed. Ways to im proving the quality of thin-sheet, cold-rolled textured transformer steel t hrough development of more active insulating coatings and efficient deposit ion techniques are discussed.