PRODUCTION OF HIGH-MAGNETIC FLUX DENSITY GRAIN ORIENTED SILICON STEEL SHEET HAVING EXTREMELY GOOD MAGNETOSTRICTION CHARACTERISTIC

摘要

PURPOSE: To provide a process for production of a grain-oriented silicon steel sheet(GO) having excellent magnetostriction characteristics by regulating a cooling rate across a magnetic transformation point, in-magnetic field cooling conditions across the magnetic transformation point or combined conditions thereof at the time of surface coating and flattening annealing of the steel sheet. CONSTITUTION: The average cooling rate from the magnetic transformation point to 350 deg.C at the time of surface coating and flattening annealing after finish annealing is specified to <=25 deg.C/sec in production of the GO by subjecting the GO to high-temp. finish annealing. The GO is cooled in a magnetic field of >=10 oersted(Oe) from the magnetic transformation point up to room tap. The average cooling rate from the magnetic transformation point to 350'C is otherwise set at <=25 deg.C/sec and the GO is cooled in the magnetic field of >=10 (Oe) from the magnetic transformation point up to room temp. As a result, the production of the grain-oriented silicon steel sheet having the extremely low magnetostriction which is the fundamental cause for noises of a voltage transformer is made possible.