| 摘要 |
PROBLEM TO BE SOLVED: To produce a grain oriented silicon steel sheet capable of giving excellent film characteristic and magnetic properties even in the case of a large sized silicon steel sheet coil and even in the case where MgO roasted in a rotary kiln is used as an essential component of a separation agent at annealing. SOLUTION: As MgO for a separation agent at annealing, MgO, prepared by roasting an Mg-element-containing raw material which forms MgO by roasting, hydrating the resultant MgO to form Mg(OH)2 having (4.0 to 15.0) m<2> /g specific surface area, 25-150 nm (c)-axis average diameter of crystallite, and 50 to 1,200 nm (a)-axis average diameter, and then roasting this Mg(OH)2 again in a rotary kiln, is used. This MgO has 40-100 sec 40%CAA value, 120-400 sec 80%CAA value, (12 to 35) m<2> /g specific surface area, and 0.7-2.8 wt.% 1 g. loss. |
