Title:
PRODUCTION OF GRAIN-ORIENTED SILICON STEEL SHEET HAVING ULTRALOW IRON LOSS
Document Type and Number:
Japanese Patent JP2678850
Kind Code:
B2
Abstract:
PURPOSE: To produce a grain-oriented silicon steel sheet reduced in isolated inclusions under the surface by electrostatically applying a specific separation agent at annealing at the time of laminating primarily recrystallized sheets and then performing secondary recrystallization and purification at the time of finish annealing.
CONSTITUTION: A strip of a silicon steel has a composition consisting of, by weight, 0.8-4.8% Si, 0.012-0.05% acid-soluble Al, ≤0.01% N, and the balance Fe with inevitable impurities. This strip is cold-rolled once or is cold-rolled twice or more while process- annealed between the cold rolling stages so as to be formed to the prescribed sheet thickness, followed by primary recrystallization annealing and finish annealing. At the time of laminating the primarily recrystallized sheets before finish annealing, a powder mixture of Al2O3 and TiO2 is electrostatically applied as a separation agent at annealing, and, at the time of finish annealing secondary recrystallization and purification are done while keeping the surface in a mirror-finished state. By using Al2O3, as an essential component of the separation agent at annealing and also adding TiO2 by 5-30%, the ruggedness in the steel sheet surface causing deterioration in iron loss characteristics can be smoothed.
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Inventors:
Ushigami Yoshiyuki
Takeo Nagashima
Takeo Nagashima
Application Number:
JP417892A
Publication Date:
November 19, 1997
Filing Date:
January 13, 1992
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
C21D1/26; C21D1/70; C21D8/12; C21D9/46; C22C38/00; C22C38/06; H01F1/16; (IPC1-7): C21D9/46; H01F1/16
Attorney, Agent or Firm:
Kazuo Ozeki