| 摘要 |
<p>PROBLEM TO BE SOLVED: To form a tension insulating film having extremely excellent coating film adhesion compared to that of the conventional coating films on the surface of a grain oriented silicon steel sheet. SOLUTION: In a tension insulating coating film treating system for a grain oriented silicon steel sheet which has been subjected to finish annealing, the inlet side of a coating treating tank for a tension insulating coating film is provided with an immersing and nitriding unit provided with an immersing tank 7 composed of a bath of chlorides essentially consisting of SiCl4 and a nitriding chamber 8 in which a steel sheet 2 after immersion into the chloride bath is exposed to a nonoxidizing atmosphere contg. nitrogen to form a nitrogen-rich layer on the surface.</p> |
