Method of producing grain-oriented electrical steel sheet...

Metal treatment – Process of modifying or maintaining internal physical... – Magnetic materials

Reexamination Certificate

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C148S111000

Reexamination Certificate

active

07833360

ABSTRACT:
The invention provides a method of producing a grain-oriented electrical steel sheet of the complete solid solution nitrided type that is good in glass film formation and excellent in magnetic properties, which method comprises: C: 0.025 to 0.09%, hot-rolling the steel slab containing Si: 2.5 to 4.0% and acid-soluble Al into a hot-rolled steel strip; controlling the rate at which N contained in the hot-rolled steel strip is precipitated as AlN to a precipitation rate of 20% or less; conducting hot-rolled strip annealing and cold rolling conducting decarburization-annealing combined with primary recrystallization by during the former part of the process in an atmosphere whose PH2O/PH2is 0.30 to 0.70 and then during the latter part thereof in an atmosphere whose PH2O/PH2is 0.20 or less, thereby making the circular equivalent average grain diameter of the primary recrystallization grains 7 μm to less than 18 μm; nitriding the strip as it travels in a mixed gas of hydrogen, nitrogen and ammonia; controlling the steel strip oxygen concentration before secondary recrystallization annealing calculated based on strip thickness of 0.30 mm (oxygen content: So) to 450 ppm to 700 ppm inclusive; applying a coat of annealing separator; and then conducting secondary recrystallization annealing in an atmosphere that, while the temperature at the hottest coil outer periphery point is between room temperature and 950° C., is controlled to a nitrogen atmosphere containing oxygen: 25 to 75% wherein the balance is hydrogen and PH2O/PH2is 0.01 to 0.15.

REFERENCES:
patent: 2599340 (1952-03-01), Littmann et al.
patent: 5244511 (1993-09-01), Komatsubara et al.
patent: 6280534 (2001-08-01), Senda et al.
patent: 6635125 (2003-10-01), Kosuge et al.
patent: 40-15644 (1965-07-01), None
patent: 58-023414 (1983-02-01), None
patent: 05-112827 (1993-05-01), None
patent: 11-256242 (1999-09-01), None
patent: 11-279642 (1999-10-01), None
patent: 2000-199015 (2000-07-01), None
patent: 2001-152250 (2001-06-01), None
patent: 2003-166019 (2003-06-01), None
patent: 2003-342642 (2003-12-01), None
patent: 2005-226111 (2005-08-01), None
International Search Report dated May 1, 2007 issued in corresponding PCT Application No. PCT/JP2007/050744.
J. D. Embury et al., “On Dislocation Storage and the Mechanical Response of Fine Scale Microstructures,”Acta metall. Mater., vol. 42, No. 6, pp. 2051-2056, 1994.
T. Kumano et al., “Influence of Primary Recrystallization Texture through Thickness to Secondary Texture on Grain Oriented Silicon Steel,”ISIJ International, vol. 43, No. 3, pp. 400-409, 2003.
Y.Yoshitomi et al., “Prediction Method of Sharpness of {110}<001> Secondary Recrystallization Texture of Fe-3%Si Alloy,”Materials Science Forum, vols. 204-206, pp. 629-634, 1996.

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