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

Effect of electrically insulating coatings on anisotropic features of magnetic properties of various sorts of cold-rolled anisotropic transformer steel 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 steels below insulating coatings, and the physical causes of this effect have been elucidated. Feasibility of using the technique of visualization of magnetic domains in a transformer steel beneath an electrically insulating layer for testing indirectly the material quality has been analyzed. Ways to improving the quality of thin-sheet, cold-rolled textured transformer steel through development of more active insulating coatings and efficient deposition techniques are discussed.