| 摘要 |
PURPOSE:To easily obtain a silicon steel sheet reduced in iron loss by subjecting a hot rolled strip of silicon steel, in which respective contents of Si, acid soluble Al, N, and Fe are specified, to plural cold rollings while performing annealing between the cold rolling stages and then applying finish annealing to the resulting sheet under specific conditions. CONSTITUTION:A silicon steel having a composition consisting of, by weight, 2-4.8% Si, 0.008-0.05% acid soluble Al, <=0.01% N, and the balance Fe is refined. Cold rolling is applied to a hot rolled strip of the above-mentioned silicon steel twice or more while performing annealing between the cold rolling stages until the prescribed sheet thickness is reached. Subsequently, after primary recrystallization annealing is performed, alumina as a separation agent at annealing is electrostatically applied to the resulting steel sheet and finish annealing is performed. At this time, the atmosphere is regulated so that it consists of 0-95% N2 and the balance H2, temp. rise rate at the time of finish annealing is regulated to 50 deg.C/Hr, and the above steel sheet is subjected to temp. rise up to 920-1150 deg.C and held at this temp. for >=5hr. |
