| 摘要 |
PURPOSE:To produce the title low-iron-loss grain-oriented electrical steel sheet having a nice-looking coating film by preannealing a cold-rolled sheet under specified condition prior to decarburization annealing to obtain a recovery crystal aggregate texture, and controlling the surface oxidation amt. to a low level. CONSTITUTION:The cold-rolled sheet having final thickness is preannealed prior to decarburization annealing at 600-650 deg.C for 30sec to 10min in the nonoxidizing atmosphere having the dew point of <=0 deg.C or preferably <-10 deg.C. As a result, the formation of Fe3O4 on the surface can be preferably controlled, a forsterite coating film good for finish annealing is formed, a grain-oriented electrical steel sheet having a nice-looking coating film is obtained, the crystal grain is not strained in flattening annealing, and the magnetic flux density is not deteriorated. |
