METHOD FOR MANUFACTURING EXTREMELY THIN GRAIN-ORIENTED SILICON STEEL SHEET HAVING LOW IRON LOSS AND HIGH MAGNETIC INDUCTION

摘要

PURPOSE: A method for manufacturing extremely thin grain-oriented silicon steel sheet having low iron loss and high magnetic induction is provided to improve rolling productivity and lower production cost by performing two times of rolling and final annealing at a dry hydrogen atmosphere. CONSTITUTION: In a method for manufacturing an extremely thin silicon electrical steel sheet having thickness of 0.23 mm or less by passing a hot rolled silicon steel sheet manufactured by melting and hot rolling through processes of first cold rolling, first intermediate annealing, second cold rolling and recrystallization annealing at a dry hydrogen atmosphere, the method is characterized in that a reduction ratio of the second cold rolling process is controlled to from 30% to less than 80%, and an atmospheric temperature of the recrystallization annealing process at a dry hydrogen atmosphere is controlled to 850 to 1,350 deg.C. In a method for manufacturing an extremely thin silicon electrical steel sheet having thickness of 0.23 mm or less by passing a hot rolled silicon steel sheet manufactured by melting and hot rolling through processes of first cold rolling, first intermediate annealing, second cold rolling, second intermediate annealing, third cold rolling and recrystallization annealing at a dry hydrogen atmosphere, the method is characterized in that a reduction ratio of the third cold rolling process is controlled to from 30% to less than 80%, and an atmospheric temperature of the recrystallization annealing process at a dry hydrogen atmosphere is controlled to 850 to 1,350 deg.C, wherein the hot rolled silicon steel sheet comprises 4 wt.% or less of Si, 0.01 wt.% or less of C, 0.01 wt.% or less of N, 0.05 wt.% or less of S, 0.01 wt.% or less of soluble Al and a balance of Fe and other inevitable impurities.