| 摘要 |
PURPOSE:To obtain a protective coating material for annealing which gives a directional silicon steel plate with superior magnetic properties when used in the finish annealing of a directional silicon steel plate by adding sulfuric acid or >=1 kind of sulfate to unhydrated magnesium oxide by a prescribed amount as S. CONSTITUTION:Sulfuric acid or >=1 kind of sulfates is added to unhydrated magnesium oxide by 150-1,000, especially 300-600ppm as S to obtain the desired protective coating material for anneaing for a directional silicon steel plate. It is effective to use >=1 kind of sulfates such as iron surfate, manganese sulfate, nickel sulfate or magnesium sulfate as said sulfate. When the protective coating material is used, the resulting directional silicon steel plate has 1.919-1.940 magnetic flux density B8 and 1.05-1.10 iron loss W17/50. |
