| 摘要 |
<P>PROBLEM TO BE SOLVED: To prescribe a method for introducing ammonia, by which, in the production of a nitriding-type grain-oriented magnetic steel sheet containing Al, a secondary recrystallization is secured and reduction in investment cost of a nitriding facility and facilitation of maintenance of the facility are achieved. <P>SOLUTION: When the nitrogen contents (mass%) in the 20% thickness from one surface of the steel sheet and in that from the other surface in the nitriding treatment are defined as σN1 and σN2 respectively, the σN1 and the σN2 are within in the range satisfying the formula (1): D=¾σN1-σN2¾/tN≤0.40, wherein tN is the nitrogen content (mass%) of the whole sheet thickness after nitriding. <P>COPYRIGHT: (C)2011,JPO&INPIT |
