| 摘要 |
PURPOSE:To improve the iron loss characteristic of a grain-oriented electrical steel sheet by applying locally a heating-cooling cycle on the surface of the grain-oriented electrical steel sheet subjected to finish rolling thereby forming a thermal strain region. CONSTITUTION:Laser light 4 or the like is scanned on the surface of a grain- oriented electrical steel sheet 1 subjected to finish annealing at a speed of vmm./ sec over the entire width by a scanning mechanism 5. Said light is further condensed at the size of a diameter dmm. on the surface of the sheet 1 by a condensing optical system 6. On the other hand, the sheet 1 is run in such a way that the irradiating space (l) of the light 4 attains a prescribed distance. A thermal strain region by the heating-cooling cycle is thus formed on the surface of the sheet 1 over the entire width thereof, by which the iron loss characteristic is improved. Even if the above-mentioned method is applied to a surface coated steel sheet, the film thereon is kept free from damage. |
