| 摘要 |
PURPOSE:To produce the low-iron loss grain-oriented electrical steel sheet having a high magnetic flux density by forming a hard glassy film on the surface of the grain-oriented electrical steel sheet, then applying a solid lubricating material for an insulating film thereon and drying the coating, then forming grooves thereon with a toothed roll and further applying a solid lubricating material thereon. CONSTITUTION:A silicon steel slab contg. <4.5wt.% Si is hot-rolled, annealed and cold-rolled to form the steel sheet of the final thickness and is then annealed at a high temp. The glassy film of a hard ceramic type essentially consisting of forsterite is applied thereon, and in succession, the solid lubricating material essentially consisting of phosphoric acid, chromic acid, etc., is applied on this steel sheet in a 0.1 to 2.5g/m<2> amt., and thereafter, the coating is dried at 200 to 350 deg.C. The grooves are formed in the direction intersecting with the cold rolling direction of the cold rolled steel sheet by using the toothed roll and further, the solid lubricating material essentially consisting of the phosphoric acid and chromic acid is applied thereon in such a manner that the total amt. of the previous coated amt. and the coated amt. of this time attains 3.5 to 5.0g/m<2>. This coating is bated at >=750 deg.C. The grain-oriented electrical steel sheet having the high magnetic flux density and the decreased iron loss is produced. |
