| 摘要 |
PURPOSE: To increase the magnetic flux density of a high magnetic flux density grain-oriented silicon steel sheet used for transformer or the like to the limit and to stably produce a product extremely low in iron loss. CONSTITUTION: At the time of producing a grain-oriented silicon steel sheet using AlN as the main inhibitor and having an intensive draft as characteristics, a steel sheet contg. 0.0005 to 0.05% Bi is subjected to secondary recrystallization finishing annealing while a temp. gradient of 0.5 deg.C/cm lower than the conventional one is applied to the steel in the boundary part between a primarily recrystallized region and a secondarily recrystallized region. Thus, at the time of producing the grain-oriented silicon steel sheet in which Bi is added and incorporated into the steel sheet stock, the product having extremely high magnetic flux density B8 of >=1.96 T can be obtd. more stably than heretofore, and it can be produced at an extremely low cost compared to the case of the conventional temp. gradient annealing method. |
