| 摘要 |
PURPOSE:To improve glass film characteristics and magnetic properties by controlling the total SiO2 content in the formed oxide film in a decarburizing annealing stage for a silicon steel sheet with a specific composition. CONSTITUTION:A slab of a silicon steel having a composition consisting of, by weight, 0.03-0.12% C, 2.5-4.5% Si, 0.03-0.20% Mn, 0.01-0.06% S, 0.01-0.05% acid-soluble Al, 0.0030-0.012% N, 0.03-0.5% Sn, 0.02-0.3% Cu, and the balance Fe with inevitable impurities, is rolled, annealed, rapidly cooled, pickled, and then cold-rolled to the final sheet thickness. In the successive decarburizing annealing stage, the components in the formed oxide film are controlled so that Fe and Mn components in [(Fe, Mn)O]a[SiO2]b become 0.15-0.60 expressed in terms of (FeO+MnO)/(total SiO2 in the oxide film) and also the total SiO2 in the oxide film becomes (0.4 to 1.6)g/m<2>. Subsequently, a separation agent at annealing is applied and final finish annealing is done. By this method, a tight glass film can be formed in the early stage in a finish annealing course. |
