Ultra-high magnetic flux density unidirectional electrical sheet excellent in high magnetic field iron loss and coating characteristics and production method therefor

摘要: A unidirectional electrical sheet which comprises ferrite and at least 0.01 ppm less than 1000 of Bi in terms mass % present on a primary coating interface, is produced by subjecting the to preliminary annealing 700°C for 1-20 sec before decarburization anealing controlling an atmosphere this temperature region, or maximum reaching B (°C) final cold rolling within range represented expression, -10×ln(A)+1100≤B≤10×ln(A)+1220, according content (ppm) heating steel cold-rolled thickness, being annealed, 10 rate 100°C/sec, immediately it annealing, TiO2 amount against 100 pts wt MgO C (g/m2) that are used when applying drying anneal separating agent mainly containing range, A0.8≤B×C≤400, (ppm).