| 摘要 |
PURPOSE:To manufacture the monodirectional silicon steel sheet containing Al permissible high magnetic flux density, by controlling the partial pressure of N2 in the atmosphere at temperatures over through the period ending with completion of the secondary recrystallization is the heating pass for the final annealing process being executed for the cold relled Al containing silicon steel. CONSTITUTION:After hot rolling, annealing and cold rolling the slab of Al containing silicon steel, the final annealing process is executed; hereupon, over through the heating pass, the partial pressure of N2 in the annealing atmosphere of 800-950 deg.C is controlled to under 20% of the total pressure. Hereby, the preparatory layer for coarsening the crystal grain in the skin layer of the sheet is formed. Following to this, the partial pressure of N2 is kept above 3%, preferably above 10%, over through the period from the start of recrystallization to the end point of the secondary recrystallization at 1100 deg.C. As a result of this treatment, the concentration of AlN in the skin layer is appropriately reduced, and the characteristic with high magnetic flux density, that is B8 above 1.90, can be stably obtained. |
