| 摘要 |
PURPOSE: To produce a grain-oriented silicon steel sheet improved in magnetic properties by subjecting a steel contg. specified amounts of C and Si to cold rolling, thereafter executing specified decarburizing annealing, coating the same with a separation agent consisting essentially of MgO for annealing and executing final finish annealing. CONSTITUTION: A steel slab contg., by weight, 0.02 to 0.1% C and 2 to 4% Si is heated to a high temp. of about >=1300 deg.C and is thereafter subjected to hot rolling. The obtd. hot rolled sheet is subjected to cold rolling once or twice including process annealing and is finished into a final sheet thickness. After that, the cold rolled sheet is subjected to decarburizing annealing, is thereafter coated with a separation agent for annealing consisting essentially of MgO and is subjected to final finish annealing. In the method for producing this grain-oriented silicon steel sheet, as for the steel sheet before the final finish annealing and after the decarburizing annealing, the decarburizing annealing is executed under the conditions in which, in the case the pickling loss per side after its immersion for one min. into an aq. soln. of hydrochloric acid is defined as (p)g/m<2> and the hydration quantity after its hydration at 20 deg.C for 60min per MgO as a separation agent for annealing is defined as (h)%, the inequality of (p.h)<=3.0 is regulated, and preferably, the upper limit of (p.h) satisfies about 0.8. |
