| 摘要 |
<p>When an area ratio of oxides occupying a steel sheet cross section perpendicular to a rolling direction at a position of a depth t from a surface of a decarburized nitrided steel sheet is set to b (t), an area ratio of Fe-based oxides is set to a (t), and a ratio of the Fe-based oxides to all the oxides at the position of the depth t is set to F (t) = a (t)/b (t), it is controlled such that F (t) becomes a maximum value inside the steel sheet at the depth t from the surface of the decarburized nitrided steel sheet of not less than 0.1 µ m nor more than 1.2 µ m, and an average value of values of F (t) at the depth t from the surface of the steel sheet falling within a range of 0.1 µ m to 0.6 µ m becomes not less than 0.05 nor more than 0.3, and thereby it becomes possible to make change in inhibitors in a finish annealing step uniform to form a good glass film.</p> |
