PURPOSE: To stabilize the magnetic properties of a grain-oriented silicon steel sheet used mainly as iron core material for electrical equipment such as transformer, particularly a grain-oriented silicon steel sheet having a thickness as thin as 0.10-0.25mm.
CONSTITUTION: In a series of stages where a steel slab is hot-rolled and the resulting hot rolled plate is cold-rolled twice or more, while process-annealed between the cold rolling stages, and is subjected to decarburizing annealing and then to final finish annealing, this hot rolled plate is rolled down, prior to the above cold rolling, at 0.5-15% reduction of area by means of a rolling mill, where (roll diameter)/(plate thickness)=50 is satisfied, and is then subjected to hot rolled plate annealing at 700-1100°C. By this method, the occurrence of abnormal structure where secondary recrystallization is not developed can be prevented and stable magnetic properties free from variance can be provided over the whole length, e.g. of a coil.
TAKAMIYA TOSHITO
TAKEUCHI FUMIHIKO
OBARA TAKASHI
Next Patent: PRODUCTION OF AS-ROLLED TYPE ULTRAHIGH TENSILE STRENGTH RESISTANCE WELDED TUBE FOR VEHICLE DOOR IMPA...