ELECTRICAL STEEL SHEET WITH ORIENTED GRAIN STRUCTURE Russian patent published in 2019 - IPC H01F1/18 C21D8/12 C22C38/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, namely to a sheet of electrical steel with grain-oriented structure used as a material for transformer cores. Sheet contains the base metal of the steel sheet and an insulating film. Grooves are made on the surface of the base metal of the steel sheet, passing in the direction crossing the rolling direction and in the direction of the depth of the groove, which coincides with the direction of the sheet thickness. In the longitudinal section of the groove, including the direction of its length and the direction of the thickness of the sheet, the arithmetic average of the height Ra of the roughness curve characterizing the relief of the zone of the bottom of the groove is from 1 to 3 mcm, and the average RSm length of the element of the roughness curve characterizing the relief of the zone of the groove bottom is from 10 to 150 mcm. In the cross section of the groove perpendicular to the direction of its length, the insulating film contains iron-containing particles with a diameter of equivalent circumference from 0.1 to 2 mcm in the zone, stretching 10–500 mcm in the direction perpendicular to the thickness of the sheet from the base point, which is the boundary between this groove and the surface of the steel sheet, to points remote from the groove in the cross section of the groove. Ratio of the area of iron-containing particles to the area of the zone containing iron-containing particles is greater than or equal to 0.1 % and less than 30 %, and iron-containing particles have a chemical composition containing in wt. %: 80–100 Fe, 0–10 Si and 0–10 Mg.

EFFECT: increased corrosion resistance of a sheet having grooves on its surface to reduce the size of magnetic domains.

5 cl, 14 dwg, 5 tbl