To obtain a grain oriented silicon steel sheet excellent in iron loss characteristics by artificially regulating secondarily recrystallized particles.
In the method for producing a series of grain oriented silicon steel sheets, a silicon steel sheet slab contg., by weight, 2.5 to 4.0% Si, ≤-0.075% C, 0.05 to 0.45% Mn, ≤0.015% S, 0.010 to 0.040% acid soluble Al, ≤0.010% N, 0.02 to 0.15% Sn, and the balance Fe with inevitable impurities is heated at ≤1280°C and is thereafter subjected to hot rolling, and hot rolled sheet annealing is executed or is not executed to regulate its sheet thickness to product one in final cold rolling ratio of ≥80%, and decarburizing annealing, nitriding treatment and finish annealing are executed. In this case, the cold rolled sheet is coated with a P compd., an S compd. and oxide in the range of 90 to 45°to the rolling direction, at 5 to 25 mm interval in the rolling direction and at 0.5 to 3 mm width in a linear shape or in the shape of a broken line to regulate the secondarily recrystallized grains to suitable dimensions.
FUJII NOBUNORI
FUJII HIROYASU
KUROKI KATSURO
TANAKA OSAMU
NITTETSU PLANT DESIGNING CORP