Patents by Inventor Chikako Fujinaga

Chikako Fujinaga has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6063214
    Abstract: A method of producing a steel sheet useful for making cans. The method steps include hot-rolling a slab consisting of about 0.0005 to 0.01 wt % C, about 0.001 to 0.04 wt % N (the total of C and N is at least about 0.008 wt %), about 0.05 to 2.0 wt % Mn, about 0.005 wt % or less Al, about 0.01 wt % or less O at a finish rolling temperature within a temperature range of about the Ar.sub.3 point to about 950.degree. C., coiling the rolled material at a temperature range of about 400 to 600.degree. C., cold rolling the material, continuously annealing the material at a temperature higher than the recrystallization temperature, and then temper-rolling the material. The steel sheet exhibits good workability during can making and which can be formed into a can having high strength.
    Type: Grant
    Filed: August 8, 1994
    Date of Patent: May 16, 2000
    Assignee: Kawasaki Steel Corporation
    Inventors: Chikako Fujinaga, Akio Tosaka, Toshiyuki Kato, Kaku Sato, Hideo Kuguminato, Yoshihiro Okawa
  • Patent number: 5725697
    Abstract: A method of manufacturing a cold-rolled can steel sheet having less planar anisotropy and achieving good workability. Rough-rolling is first performed on a continuously-cast slab. The slab has a composition essentially consisting of: C: 0.004 wt % or lower; Mn: 0.05-0.5 wt %; P: 0.02 wt % or lower; Al: 0.005-0.07 wt %; N: 0.004 wt % or lower; and Nb: 0.001-0.018 wt %, the rest being Fe and unavoidable impurities. A resultant sheet bar is then subjected to hot rolling which is completed at a finishing rolling temperature at an Ar.sub.3 transformation point or higher. The resultant sheet bar is coiled at a temperature range from 450.degree.-700.degree. C. Subsequently, the resultant sheet bar undergoes primary cold rolling before continuous annealing, which is performed at a recrystallization temperature or higher, and secondary cold rolling. The primary and secondary cold rolling are respectively performed at reduction ratios satisfying the following conditions of:88%.gtoreq.CR.sub.1 %+0.36.times.CR.sub.2 .
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: March 10, 1998
    Assignee: Kawasaki Steel Corporation
    Inventors: Chikako Fujinaga, Akio Tosaka, Toshiyuki Kato, Kaku Sato, Hideo Kuguminato
  • Patent number: 5587027
    Abstract: A method for manufacturing a canning steel sheet with non-aging property and superior workability uses, as a starting material, an ultra-low-carbon steel slab composed of from 0.0015% to 0.0100% by weight C, up to 0.20% by weight Si, from 0.10% to 1.20% by weight Mn, from 0.02% to 0.10% by weight Al, from 0.005% to 0.040% by weight P, up to 0.015% by weight S, up to 0.005% by weight N, and balance iron and unavoidable impurities. The manufacturing method includes hot rolling the steel, cold rolling the steel at a reduction ratio not less than 70% after pickling, and recrystallization annealing the steel by using a continuous annealing furnace in an atmosphere having a hydrogen content not less than 3% and a dew point not lower than -20.degree. C. at a temperature not lower than 730.degree. C. so that the content of remained C in the steel is kept less than 0.0015% by weight. At least one element selected from Nb, Ti and B may be added in predetermined amounts to the above composition.
    Type: Grant
    Filed: February 15, 1995
    Date of Patent: December 24, 1996
    Assignee: Kawasaki Steel Corporation
    Inventors: Akio Tosaka, Chikako Fujinaga, Toshiyuki Kato, Kaku Sato, Hideo Kuguminato
  • Patent number: 5534089
    Abstract: A method of manufacturing a small planar anisotropic high-strength can steel plate. Hot-rolling is first performed on a steel slab at an Ar.sub.3 transformation point or higher to obtain hot rolled steel strip. The slab has a composition which essentially consists of and which satisfies the conditions of: C.ltoreq.0.004%, Si.ltoreq.0.02%, Mn=0.5%-3%, P.ltoreq.0.02%, Al=0.02%-0.05%, 0.008%.ltoreq.N.ltoreq.0.024%, and the rest being Fe and unavoidable impurities, wherein the conditions have the relationship of:Al%/N%>2. Then, the resultant strip is cooled at a cooling rate of 10.degree. C./s or higher so as to reach a temperature of 650.degree. C. or lower. The resultant strip is further coiled at a temperature in a range of from 550.degree. C. to 400.degree. C. Cold-rolling is performed on the resultant strip at a reduction ratio of 82% or higher preceded by removing a scale to obtain cold rolled steel strip.
    Type: Grant
    Filed: December 20, 1994
    Date of Patent: July 9, 1996
    Assignee: Kawasaki Steel Corporation
    Inventors: Chikako Fujinaga, Akio Tosaka, Toshiyuki Kato, Kaku Sato
  • Patent number: 5496420
    Abstract: There is provided an ultra-thin and high strength three-piece can-making plated steel sheet which is excellent in weldability and flange forming processibility containing C .ltoreq. about 0.004 wt %, Si.ltoreq. about 0.03 wt %, Mn: about 0.05-0.6 wt %, P.ltoreq. about 0.02 wt %, S.ltoreq. about 0.02 wt %, N.ltoreq. about 0.01 wt % Al: about 0.005-0.1 wt %, Nb: about 0.001-0.1 wt % and the balance of inevitable impurities. The steel sheet has a maximum recrystallization grain size of 30 .mu.m or less and a ratio of area of 50% or more which is occupied by recrystallization grains of about 5-25 .mu.m.
    Type: Grant
    Filed: July 1, 1994
    Date of Patent: March 5, 1996
    Assignee: Kawasaki Steel Corporation
    Inventors: Hideo Kuguminato, Toshikatsu Kato, Chikako Fujinaga, Kyoko Hamahara
  • Patent number: 5360676
    Abstract: A raw plated steel sheet for can comprises recrystallized particles containing approximately C<0,004%, Si<0.03%, Mn:0.05-0.6%, P<0.02%, S<0.02%, N<0.01%, Al:0.005-0.1%, Nb:0,001-0.1%, B:0.0001-0.005% in weight. The maximum diameter of a particle is less than about 30 .mu.m, and an area ratio of particles ranging about 5-25 .mu.m being more than about 50%. Such a steel sheet has excellent processing characteristics and good uniformity in product quality.
    Type: Grant
    Filed: April 6, 1993
    Date of Patent: November 1, 1994
    Assignee: Kawasaki Steel Corporation
    Inventors: Hideo Kuguminato, Toshikatsu Kato, Chikako Fujinaga, Kyoko Hamahara