GRAIN-ORIENTED SILICON STEEL SHEET HAVING LOW IRON LOSS AND ITS PRODUCTION

摘要

PURPOSE:To improve the grain size and arrangement of secondary recrystallization and to obtain a grain-oriented silicon steel sheet having a low iron loss by subjecting a hot rolled silicic steel sheet to cold rolling including intermediate annealing and coating an accelerator for development of secondary recrystallization thereon after decarburization and primary recrystallization annealing then subjecting the steel sheet to finish annealing. CONSTITUTION:The hot-rolled silicic steel sheet is subjected to cold rolling including intermediate annealing to a final sheet thickness and is then subjected to decarburization and primary recrystallization annealing. The accelerator for development of secondary recrystallization such as SrO powder is discretely stuck to the surface of such steel sheet. A separating agent for annealing consisting essentially of MgO is then coated thereon and the steel sheet is subjected to final finish annealing and finish coating. The grain-oriented silicon steel sheet of which the grain size distribution of the secondary recrystallization grains is made into the duplex grain size distribution consisting of 40- 80% number ratio of crystal grains having 1.0-2.5mm. grain size and >=15% number ratio of the crystal grains having 5.0-10.0 grain size and which has the low iron loss is thus obtd. Such silicon steel sheet has the exceptionally outstanding iron loss characteristic without having the deteriorated magnetic flux density.