TAPE CORE Russian patent published in 2023 - IPC H01F27/245 H01F1/147 C22C38/02 C21D8/12 

FIELD: electrical engineering.

SUBSTANCE: strip core has a substantially rectangular strip core body in side view. The main body of the strip core includes a portion of anisotropic electrical steel sheets in which the first flat portions and the corner portions alternate continuously in the longitudinal direction, and the angle formed by the two first flat portions adjacent to each other, with each corner portion between them, is 90°, are stacked in the sheet thickness direction, and have a substantially rectangular laminated structure in side view. In a side view of the anisotropic electrical steel sheet, each of the corner portions has two or more curved portions having a curved shape and a second flat portion between adjacent curved portions, and the sum of the bending angles of the curved portions in one corner portion is 90°. The curved portion in the side view has an inner radius of curvature r of 1 mm or more and 5 mm or less. Sheets of anisotropic electrical steel have a chemical composition containing, wt.%: Si: 2.0 to 7.0, with a remainder of Fe and impurities, and have a Goss-oriented texture. The frequency of existence of subgrain boundaries in the region inside 9 mm in the direction perpendicular to the boundary with the curved part satisfies the following formula (Nac+Nal)/Nt≥ 0.010(1) where, Nt is the total number of grain boundary detection positions in the region of the first flat portion and the second flat portion adjacent to the curved portion, and Nac and Nal are each the number of determination positions at which subgrain boundaries can be identified in a direction parallel and a direction perpendicular to the boundary of the curved part.

EFFECT: increasing the efficiency of the core by reducing magnetic losses during bending of the core sheets.

5 cl, 9 dwg, 12 tbl