SHEET OF ANISOTROPIC ELECTROTECHNICAL STEEL AND METHOD FOR MANUFACTURE THEREOF Russian patent published in 2022 - IPC C23C28/04 C23C26/00 C22C38/34 C23C8/14 C21D9/46 H01F1/147 H01F1/18 

FIELD: metallurgy.

SUBSTANCE: present invention relates to a sheet of anisotropic electrotechnical steel used as a material of a metal core for a transformer, as well as to a method for manufacture thereof. The sheet of anisotropic electrotechnical steel comprises the main steel sheet, an intermediate layer of an oxide film, located on the main steel sheet, containing SiO₂, with an average thickness of 1.0 nm to 1.0 mcm, and an insulating coating with tension, located on the intermediate layer of an oxide film. When analysing the surface of the intermediate layer of an oxide film using infrared reflective spectroscopy, the peak intensity I_A originating from SiO ₂ and existing at a wave number of 1,250 cm^-1 and the peak intensity I_B originating from Si(Mn)O_x and existing at a wave number of 1,200 cm^-1 satisfy the following formula I_B/I_A ≥ 0.010. The method for manufacturing a sheet of anisotropic electrotechnical steel includes forming an intermediate layer of an oxide film on a steel sheet, wherein, in the process of formation of the layer of an oxide film, the annealing is executed provided that the temperature of annealing T1 is 600 to 1,200°C, time of annealing is 5 to 200 s, the degree of oxidation P_H2O/P_H2 is 0.15 or less, and the average heating rate HR1 in the temperature range from 100 to 600°C is 10 to 200°C /s. In order to form an insulating coating, a solution is applied and hardened by heating, producing an insulating coating with tension.

EFFECT: formation of an insulating coating with tension with excellent adhesion without deterioration of the magnetic characteristics and stability thereof on the surface of the sheet of anisotropic electrotechnical steel after final annealing.

4 cl, 1 dwg, 4 tbl, 3 ex