| 摘要 |
PURPOSE:To obtin an electromagnetic steel sheet having a magnetic property and an insulating property under a stable condition, while improving an iron loss property, by forming tension films having different thickness on the opposite surfaces of the electromagnetic steel sheet, irradiating laser beams to the surface of the thinner film, and then coating the thinner film with an insulating film at a proper temperature. CONSTITUTION:Tension films having different thickness are formed on the opposite surfaces of an electromagnetic steel sheet in a proper manner. Laser beams are irradiated to the surface of the thinner tension film to form laser- irradiated marks. An insulating film is then applied to the laser-irradiated surface in a temperature range not to eliminate the laser-irradiating effect, e.g. under the condition that the temperature of the sheet is held below 600 deg.C. According to this method, the iron loss property of the electromagnetic steel sheet is remarkably improved without reduction of adhesiveness, space factor ratio resistance and a voltage-withstanding property. |
