METHOD FOR MANUFACTURING ELECTROTECHNICAL STEEL SHEET WITH ORIENTED GRAIN STRUCTURE AND ELECTROTECHNICAL STEEL SHEET WITH ORIENTED GRAIN STRUCTURE Russian patent published in 2021 - IPC C22C38/60 C21D8/12 H01F1/147 H01F1/18 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, namely, to production of an electrotechnical steel sheet with an oriented grain structure used as a core material for transformers. A slab with a component composition containing, % wt.: C: 0.02 or more and 0.10 or less, Si: 2.5 or more and 4.5 or less, Mn: 0.01 or more and 0.15 or less, S and Se total: 0.001 or more and 0.050 or less, acid-soluble Al: 0.01 or more and 0.05 or less, and N: 0.002 or more and 0.015 or less, Fe and impurities the rest, is heated to the temperature of 1,280 to 1,450°C and hot-rolled to produce a hot-rolled steel sheet. The hot-rolled steel sheet is annealed and cold-rolled once, twice or more with intermediate annealing between the passes to produce a cold-rolled steel sheet. Annealing is executed for primary recrystallisation of the cold-rolled steel sheet, and a separation annealing agent including MgO is applied to the surface thereof. The final annealing is then executed, an insulating coating is applied, and levelling annealing is executed. During the annealing for primary recrystallisation, in the process of increasing the temperature, the average rate of increasing the temperature V (°C/s) in the temperature range of 550 to 700°C equals 400°C/s or more, the value T/L (°C/mm), which is the ratio of the value T of increasing the temperature (°C) in a series of processes of increasing the temperature, including the increase in the temperature in the temperature range of 550 to 700°C, to the heated length L (mm) in the series of processes of increasing the temperature, equals 0.1 ≤ T/L ≤ 4.0, and the tensile stress S (H/mm²) applied to the cold-rolled steel sheet in the direction of movement thereof equals 1.96 ≤ S ≤ (19.6-1.96 x T/L).

EFFECT: manufactured sheets have low losses in iron and an improved shape of the surface.

2 cl, 7 dwg, 8 tbl, 5 ex