Title:
METHOD FOR CONTROLLING NITROGEN CONTENT IN GRAIN-ORIENTED MAGNETIC STEEL SHEET
Document Type and Number:
Japanese Patent JP2582988
Kind Code:
B2
Abstract:
PURPOSE: To stabilize nitriding content and to manufacture a grain-oriented magnetic steel sheet having excellent magnetic characteristic by specifying and controlling condition at the time of nitriding the grain-oriented magnetic steel sheet with NH3 after decarburizing annealing.
CONSTITUTION: The grain-oriented magnetic steel sheet 6 cold-rolled to the finish sheet thickness is passed through a decarbo-annealing furnace 1 composed of a heating zone 2, soaking zone 3, reducing zone 4 and nitriding zone 5, and in the heating zone 2, soaking zone 3 and reducing zone 4, by supplying a gas containing H2 gas and being wetted in humidifiers 8, 10, this steel sheet is heated in the atmosphere adjusted to each prescribed dew point and the moisture in the gas is reacted with C in the steel sheet 6 to decarburize and anneal the surface of the steel sheet and also, thin SiO2 layer is produced by oxidizing with the moisture and a part of SiO2 is reduced in the reducing zone 4. Successively, the steel sheet is sent to the nitriding zone 5, and by supplying the gas containing NH3 and H2 humidified in a humidifier 12 through gas supplying pipe 11, the surface of the steel sheet is nitrided, and an inhibitor is formed in the steel sheet 6 with a nitride at a comparatively low temp. to manufacture the grain-oriented electrical steel sheet having excellent magnetizing characteristic and iron loss characteristic.
Inventors:
KONDO YASUMITSU
MIZUGUCHI MASAYOSHI
YATSUGAYO KENICHI
MIZUGUCHI MASAYOSHI
YATSUGAYO KENICHI
Application Number:
JP25972392A
Publication Date:
February 19, 1997
Filing Date:
September 29, 1992
Export Citation:
Assignee:
SHINNIPPON SEITETSU KK
International Classes:
C21D8/12; C23C8/26; (IPC1-7): C23C8/26; C21D8/12
Attorney, Agent or Firm:
Tomoyuki Yathata (1 outside)