FIELD: metallurgy.
SUBSTANCE: invention relates to the field of metallurgy, namely to a sheet of electrical steel with a grain-oriented structure used as a material for iron cores of transformers. The sheet contains a base steel sheet containing Si and Mn, an intermediate layer located on the surface of the base steel sheet and containing silicon oxide as a main component, and an insulating coating located on the surface of the intermediate layer. When observing a cross section of an electrical steel sheet using a scanning electron microscope or a transmission electron microscope, a finish annealed film is not necessarily present on the surface of the base steel sheet, the area of which is not more than 1/2 of the area of the intermediate layer. In the area of the surface layer including the surface side of the base steel sheet and the intermediate layer, there is a Mn-poor layer in which the Mn content is lower than the average Mn content in the base steel sheet in the area at a depth of 25-30 µm from the surface of the electrical steel sheet, and in the region closer to the surface of the insulation coating than the Mn-poor layer, there is a Mn-rich layer in which the Mn content is higher than that of the Mn-poor layer.
EFFECT: resulting sheets have a high adhesion of the insulating coating.
8 cl, 7 dwg, 5 tbl, 20 ex
