ICHIHOKOSEIKEISOKOHANNOZETSUENHIMAKUKEISEIHOHO

摘要

PURPOSE:To form a crystalline tension-imparting insulating film on a grain- oriented silicon steel sheet free of an inorg. mineral film while preventing the internal oxidation. CONSTITUTION:An amorphous oxide film is formed on the surface of a steel sheet prior to the formation of a crystalline tension-imparting insulating film. Consequently, the internal oxidation caused during the formation of the insulating film is prevented, and the iron loss of a grain-oriented silicon steel sheet is remarkably improved.