| 摘要 |
PROBLEM TO BE SOLVED: To provide a separation agent for annealing capable of efficiently applying finish annealing to a high-Mn grain oriented silicon steel sheet and also to provide a method of production of a high-Mn grain oriented silicon steel sheet using the above separation agent for annealing. SOLUTION: The separation agent for annealing is composed of a mixed composition containing alumina powder of 0.5-10 μm average grain size and a V compound having V in an amount equivalent to 0.1-10 pts.wt. based on 100 pts.wt. of the alumina powder. The high-Mn grain oriented silicon steel sheet can be produced by subjecting a steel stock, having a composition which consists of, by weight, <=0.01% C, 1.5-4% Si, 1-4% Mn, 0.003-0.03% acid soluble Al, 0.001-0.01% N, and the balance Fe with inevitable impurities and in which the content of S as an inevitable impurity is regulated to <=0.015%, to hot rolling and to cold rolling, annealing the resultant steel sheet continuously in a noncarburizing atmosphere, applying the above separation agent for annealing to the steel sheet so that coating weight after drying becomes (0.5 to 10) g/m<2> , drying it, applying secondary recrystallization annealing at 825-925 deg.C, and then subjecting the steel sheet to purification annealing at 900-1050 deg.C for a time not shorter than the time determined according to purification annealing temp. |
