FIELD: metallurgy.
SUBSTANCE: invention relates to the field of metallurgy, namely to the production of a grain-oriented electrical steel sheet used as a material for the manufacture of iron cores of transformers. Hot rolling of a steel billet is carried out, having a chemical composition, in 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 up to 0.010 Bi, the rest is iron and impurities, to obtain a hot-rolled sheet. Cold rolling is carried out, and then decarburization annealing is carried out in an atmosphere with a PH2O/PH2oxidation 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 MgO is applied, followed by drying. Finish annealing is carried out with exposure at 1100-1200°C for 10 hours or more in a mixed gas atmosphere containing 50 vol.% or more of hydrogen. Excess annealing separator is removed from the surface of the sheet by washing with water using a solution with an inhibitor that is at least one of triethanolamine, amine rosin or mercaptan, while the amount of iron hydroxide and iron oxide on the surface is controlled so that it is 0.9 g/m2 or less per side. The surface of the sheet is smoothed by chemical polishing to provide an average roughness Ra of its surface of 0.10 µm 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, 10 tbl
