To provide a method of reducing noise generated when exciting a transformer iron core produced using a grain-oriented electromagnetic steel sheet, in a method of manufacturing the steel sheet for reducing iron loss by irradiating a surface with a pulse laser and forming irradiation marks in a point sequence shape on the surface.
When scanning a pulse-like laser in a direction crossing a rolling direction on the surface of the grain-oriented electromagnetic steel sheet after secondary recrystallization annealing, forming irradiation marks in a point sequence shape extending in the crossing direction on the surface of the steel sheet, and executing magnetic domain subdivision processing, the intervals of the irradiation marks are changed and made unequal without being turned to equal intervals as in a conventional technique.
OMURA TAKESHI
OKABE SEIJI
| JPH0790385A | 1995-04-04 | |||
| JPH11124629A | 1999-05-11 |
Kiyoshi Kuruma
Yamaguchi Yusuke