SILICON ELECTRIC STEEL AND METHOD OF TREATMENT THEREOF Russian patent published in 1997 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: object of invention is to manufacture anisotropic cold-rolled electric steel with clearly expressed electromagnetic characteristics. Steel contains (in wt %): carbon, at most 0.07; manganese, 0.15-0.24; silicon. 2.8-3.5; phosphorus, at most 0.015; sulfur, at most 0.005; chromium, at most 0.05; nickel, at most 0.09; copper, 0.4-0.6; aluminum, 0.017-0.030; nitrogen, according to inequality 0.015 ≅ [N+(3/8)Al] ≅ 0.017; titanium, according to inequality 0.012 ≅ [Ti+(3/8)Al] ≅ 0.014; iron, the balance. Steel is subjected to hot rolling, first cold rolling to intermediate thickness, decarbonizing annealing, second cold rolling to final thickness 0.17-0.27 mm with cogging 65-75%, final high-temperature annealing of sheets covered by thermally stable coating at temperature 1000-1150, and rectifying annealing of sheets covered by electrically insulating coating. EFFECT: increased electromagnetic characteristics of steel. 2 cl, 4 tbl