GRAIN ORIENTED ELECTRICAL STEEL SHEET HAVING GOOD ADHESIVENESS OF GLASS FILM AND LOW IRON LOSS AND PRODUCTION THEREOF

摘要

PURPOSE:To produce a grain oriented electrical steel sheet having good adhesiveness of a glass film and low iron loss by forming sharp and fine ruggedness on the surface of a rolled steel sheet of a silicon steel and forming an oxide on the surface thereof by decarburization annealing or finish annealing. CONSTITUTION:A silicon steel slab is hot rolled and is annealed, then the slab is subjected to one pass or >=2 passes of cold rolling including intermediate annealing. The rolled sheet is then subjected to decarburization annealing and further a separating agent for annealing is coated on the surface; thereafter, the rolled sheet is subjected to finish annealing. The surface of the steel sheet is activated by a mechanical means such as brush roll or sand blasting in such a manner that the sharp and fine ruggedness exists on the surface of the steel sheet before or after the above-mentioned decarburization annealing. The oxide essentially consisting of SiO2 partially plunged to the base iron side of the steel sheet by the decarburization annealing or finish annealing is thus thereby formed. The above-mentioned oxide forms the glass film having the good adhesiveness by reacting with the above-mentioned separating agent for annealing in the finish annealing. The above-mentioned film applies large tension to the steel sheet and the grain oriented electrical steel sheet having extremely low iron loss is obtd.