| 摘要 |
PURPOSE: A manufacturing method of a directional electrical steel sheet having excellent magnetism is provided to implement a recrystallization annealing consisting of heat-rising patterns including an ultra high-speed heat rising, a high-speed heat rising and an ordinary heat rising, thereby increasing the volume fraction of a minute GOS(Galdolinium oxysulfid) orientation crystal grain on a firstly recrystallized steel sheet, and improving the degree of integration of a crystal orientation after a second recrystallization. CONSTITUTION: A manufacturing method of a directional electrical steel sheet having excellent magnetism comprises the step of hot and cold rolling of a steel slab, the step of recrystallizing-annealing the steel sheet from the hot or cool rolled steel slab, the step of recrystallizing-annealing finally to manufacture directional electrical steel sheet. The recrystallization annealing includes the process of an ultra high-speed heat-rising, wherein the ultra high-speed heat rising is performed at the average heat-rising speed of more than 300°C/second; the process of a high-speed heat-rising, wherein the high-speed heat-rising is performed between more than 100°C/sec and the average heat-rising speed lower than the process the ultra high-speed heat rising after the process of the ultra high-speed heat-rising ; and the process of an ordinary heat-rising, wherein the ordinary heat-rising is performed at the average speed heat-rising speed lower than the process of the high speed heat-rising after the process of the high-speed heat-rising. The cold rolling is performed by rising the temperature of a steel sheet having to 150-400°C. The steel slab is composed of, in wt%: acid soluble Al 0.015-0.04, Mn less than 0.20, N less than 0.010, S less than 0.01, the remainder Fe and unavoidably mixed impurity components. |
