FIELD: metallurgy.
SUBSTANCE: invention relates to the field of metallurgy, namely to the production of a sheet of electrical steel with a grain-oriented structure used as a material for iron cores for transformers. Hot rolling of a steel billet is carried out, having a chemical composition, wt.%: from 0.030 to 0.100 C, from 0.80 to 7.00 Si, from 0.01 to 1.00 Mn, from 0 to 0.060 in the sum of S and Se, 0.010 to 0.065 acid soluble Al, 0.004 to 0.012 N, 0 to 0.30 Cr, 0 to 0.40 Cu, 0 to 0.50 P, 0 to 0.30 Sn, 0 to 0, 30 Sb, 0 to 1.00 Ni, 0 to 0.008 V, 0 to 0.15 V, 0 to 0.20 Nb, 0 to 0.10 Mo, 0 to 0.015 Ti, 0 to 0.010 Bi, the rest is iron and impurities, to obtain a hot-rolled sheet. Cold rolling is carried out to obtain a cold-rolled sheet, which is subjected to decarburization annealing in an atmosphere with a PH2O/PH2 oxidation state of 0.18-0.80 at a temperature of 750-900°C and a holding time of 10-600 s. An annealing separator including Al2O3 and MgO is applied at a MgO/(MgO+Al2O3) value of 5-50% and an amount of water of hydration in the annealing separator of 1.5 mass% or less, followed by drying. The sheet is finished annealed by holding at 1100-1200°C for 10 hours or more in a mixed gas atmosphere containing 50 vol.% or more of hydrogen. The excess annealing separator is removed by washing with water using a solution with an inhibitor which is at least one of triethanolamine, rosin amine, or mercaptan while ensuring that the amount of iron hydroxide and iron oxide on the sheet surface is 0.9 g/m2 or less per side. The surface of the sheet is smoothed by chemical polishing to provide an average surface roughness Ra of 0.1 mcm or less. An insulating coating is formed by applying a solution containing phosphate, colloidal silica and crystalline phosphide, and baking it at 350-1150°C, and after reducing the temperature of applying a solution containing phosphate and colloidal silica and not containing crystalline phosphide, and baking it at 350- 1150°C.
EFFECT: sheet has excellent magnetic performance and coating adhesion.
6 cl, 1 dwg, 13 tbl
