PRODUCTION OF LIGHT-GAGE GRAIN ORIENTED ELECTRICAL STEEL SHEET OF LOW IRON LOSS

PURPOSE:To produce a light-gage grain oriented electrical steel sheet of a low iron loss by executing plural times of cold rolling at respective specific drafts in the stage of subjecting a slab having a specific compsn. to hot rolling and annealing at specific temps. CONSTITUTION:The slab contg. 0.025-0.12% C, 3.0-4.0% Si, 0.04-0.15% Mn and 0.020-0.040% 1 or 2 kinds of S and Se as the basic components is heated to 1320-1430 deg.C and is subjected to hot rolling and annealing. The hot rolled sheet is then subjected to plural cold rolling including intermediate annealing to 0.10-0.20mm final sheet thickness. Such sheet is subjected to decarburization annealing, then to high-temp. finish annealing after a separating agent for annealing is coated thereon. The cold rolling is executed at 20-70% draft in the 1st rolling, 50-80% draft in the 2nd rolling and 50-70% in the 3rd rolling. The light-gage grain oriented electrical steel sheet of the low iron loss is thus stably produced.