FIELD: metallurgy.
SUBSTANCE: invention relates to metallurgy, namely to production of electrotechnical steel sheet with oriented grain structure used as material of iron cores of transformers. Heating a steel slab containing, wt.%: C: 0.100 or less; Si: from 0.80 to 7.00; Mn: from 0.05 to 1.00; diss. Al: from 0.0100 to 0.0700; N: from 0.0040 to 0.0120; Seq=S+0.406×Se: from 0.0030 to 0.0150; Cr: from 0 to 0.30; Cu: from 0 to 0.40; Sn: from 0 to 0.30; Sb: from 0 to 0.30; P: from 0 to 0.50; B: from 0 to 0.0080; Bi: from 0 to 0.0100; Ni: from 0 to 1.00, balance — Fe and impurities, to temperature less than 1,250 °C and the steel slab is hot rolled to produce a hot-rolled steel sheet. Performing hot annealing, etching and cold rolling to produce cold-rolled steel sheet with final thickness d from 0.15 to 0.23 mm, wherein the weight ratio between diss. Al and N (diss. Al/N) in the steel slab and the final thickness d of the sheet satisfy the expression: -4.17×d+3.63 ≤ diss. Al/N ≤ -3.10×d+4.84. Performing decarburizing annealing at temperature less than 1,000 °C, nitriding with provision of nitrogen content in cold-rolled sheet from 40 to 1,000 mln-1, and then finishing annealing is performed. A liquid coating is applied on a cold-rolled sheet to form an insulating coating and its subsequent baking.
EFFECT: reduced losses in steel due to reduced thickness of sheet, improved quality of decarburization, improved magnetic characteristics.
1 cl, 2 dwg, 5 tbl, 4 ex
