| 摘要 |
PURPOSE:To stably produce a grain-oriented silicon steel sheet having high magnetic flux density even if sheet thickness is reduced by subjecting a silicon steel stock containing Al and Sb to controlled cooling, application of microstrain, etc., in the cooling stage after annealing before final cold rolling. CONSTITUTION:At the time of subjecting a hot rolled plate of a silicon steel having a composition containing, by weight, 0.01-0.15% acid soluble Al and 0.005-0.04% Sb as inhibitor components to working to the final finish sheet thickness by a cold rolling method, softening is exerted prior to the final cold rolling. Successively, rapid cooling is performed down to <=500 deg.C at 15-500 deg.C/s cooling rate and microstrain of 0.05-3.0% is applied in the temp. region between the ultimate rapid cooling temp. and 200 deg.C. In the course of or after the application of this microstrain, the steel sheet is held at a temp. in the above temp. region for 60-180sec and cooled or is slowly cooled at <=2 deg.C/s cooling rate to undergo the control of carbide precipitation. Subsequently, final cold rolling is exerted at 80-95% reduction of area and primary recrystallization annealing which doubles as decarburization is performed, and, after a separation agent at annealing is applied, secondary recrystallization annealing and purification annealing are carried out. |
