| 摘要 |
PURPOSE:To manufacture a grain-oriented electrical steel sheet having small iron loss and undergoing no increase in the loss at a low cost by wetting a grain-oriented electrical steel sheet subjected to finish annealing with water or an aq. soln., grooving the steel sheet with a geared roll and carrying out washing and treatment for forming an insulating film. CONSTITUTION:An electrical steel sheet subjected to finish annealing or a grain- oriented electrical steel sheet treated to form an insulating film after finish annealing is grooved with a geared roll. Immediately before or during the grooving, water or an aq. soln. is fed to wet the steel sheet. A water soluble resin such as PVA or polyvinylpyrrolidone is suitable for use as the solute in the aq. soln. By the wetting, the wear of the edges of the gears is remarkably reduced and the formation of an ununiform film due to fine powder produced during the grooving is prevented. The grooved steel sheet is washed and then conventional treatment under tension for forming an insulating film or surface retreatment is carried out. Thus, an electrical steel sheet whose small iron loss is not increased even by strain relief annealing is obtd. |
