| 摘要 |
PURPOSE:To produce an electrical sheet having superior magnetic characteristics and insulation characteristics by producing laser traces through laser beam irradiation on the surface of the electrical sheet having undergone secondary recrystallization annealing then subjecting the same to insulation film treatment in a low temp. region. CONSTITUTION:For example, an electrical steel coil coated with an annealing release agent is finished and annealed at high temp., after which it is removed of the excess release agent according to a conventional method, thence it is subjected to flattening at 700-900 deg.C. After this, it is subjected to insulation film treatment at <=600 deg.C sheet temp., preferably <=550 deg.C, and more preferably <=500 deg.C. The electrical sheet obtained by this method is considerably improved of watt loss and as a result, the need for tension effect by the insulation film which has hitherto been industrially practised is eliminated. In addition, the use of stable treating agents, in place of costly insulation film treating agents contg. colloidal silica is made possible. |
