Title:
PRODUCTION OF GRAIN ORIENTED ELECTRICAL STEEL SHEET HAVING MIRROR FINISHED SURFACE AND EXTREMELY LOW IRON LOSS
Document Type and Number:
Japanese Patent JP2679931
Kind Code:
B2
Abstract:
PURPOSE: To produce the grain oriented electrical steel sheet having a mirror finished surfaces and extremely low iron loss by annealing a cold rolled sheet of a high-silicon steel, then subjecting this sheet to finish cold rolling to form the final sheet thickness, decarburization annealing and increased nitrogen treatment, applying a sepn. agent for annealing consisting of a specific oxide to the steel sheet and subjecting the sheet to finish annealing.
CONSTITUTION: The cold rolled sheet of the silicon steel contg., by weight %, 0.8 to 4.8% Si, 0.012 to 0.05% Sol. Al, ≤0.01% N or further contg. 0.02 to 0.3% Mn and 0.005 to 0.040% S is subjected to an annealing treatment and is then worked to the final sheet thickness by one pass or ≥2 passes of cold rolling including intermediate annealing. This cold rolled steel sheet is subjected to primary recrystallization annealing in an annealing furnace of a wet hydrogen atmosphere in order to execute decarburization in combination, then to a nitriding treatment in an NH3 atmosphere for stabilizing the secondary recrystallization; in succession, the oxides of the surfaces are removed by an acid soln. such as sulfuric acid, etc., to flatten the surfaces. A water slurry consisting of fine powder of 0.5 to 10μm of Al2O3, ZrO2 and other oxides is electrostatically applied as the sepn. agent for annealing on the steel sheet and, thereafter the steel sheet is subjected to the finish annealing. The grain oriented electrical steel sheet having the mirror finished surfaces, the low iron loss and the high magnetic flux density is thus obtd.
Inventors:
Ushigami Yoshiyuki
Takeo Nagashima
Shuichi Yamazaki
Hiroyasu Fujii
Takeo Nagashima
Shuichi Yamazaki
Hiroyasu Fujii
Application Number:
JP4381093A
Publication Date:
November 19, 1997
Filing Date:
March 04, 1993
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
C21D8/12; C21D1/70; C21D9/46; C22C38/00; C22C38/06; H01F1/16; (IPC1-7): C21D9/46
Attorney, Agent or Firm:
Tachio Chanogi (1 outside)
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