Patents by Inventor Kunihiro Senda

Kunihiro Senda 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: 6287392
    Abstract: Grain-oriented silicon steel sheet with Bi as an auxiliary inhibitor and a forsterite coating film having a Cr spinel oxide subscale of FeCr2O4 or FexMn1−xCr2O4 (0.6≦x≦1), made from a steel slab containing 0.005-0.20 wt % of Bi and 0.1-1.0 wt % of Cr.
    Type: Grant
    Filed: September 17, 1999
    Date of Patent: September 11, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Hiroaki Toda, Kunihiro Senda, Mitsumasa Kurosawa, Makoto Watanabe, Atsuhito Honda
  • Patent number: 6280534
    Abstract: Method of making a grain oriented electromagnetic steel sheet having excellent magnetic properties, by a series of steps ranging from hot rolling to final finishing annealing for a silicon steel slab containing from about 0.001 to 0.07 wt % bismuth, wherein the average cooling rate for about five seconds measured immediately after the end of hot rolling is controlled within a range of from about 30 to 120° C./second; the value of the ratio PH2O/PH2 of the atmosphere for the soaking step in decarburization annealing is adjusted within a range of from about 0.45 to 0.70; and a treatment is provided for inhibiting decomposition of the surface inhibitor during final finishing annealing.
    Type: Grant
    Filed: May 10, 1999
    Date of Patent: August 28, 2001
    Assignee: Kawasaki Steel Corporation
    Inventors: Kunihiro Senda, Toshito Takamiya, Makoto Watanabe, Mitsumasa Kurosawa
  • Patent number: 6110298
    Abstract: Grain-oriented electrical steel sheet having excellent magnetic characteristics in which shearing angles of grain directions [001] of secondary recrystallized grains from a rolling direction have an average value of about 4.degree. or less, wherein the area % of secondary recrystallized grains having a length of about 60 mm or more in the rolling-orthogonal direction is about 85% or more; with respect to recrystallized micro grains, the area % of crystal grains having a grain diameter of 2 to 20 mm is about 0.2% or more and about 10% or less; and the average value of angles formed with the steel sheet surface by grain directions [001] is about 1.5.degree. or more and about 5.0.degree. or less; in a grain-oriented electrical steel sheet of a high magnetic flux density (B.sub.8 .gtoreq.1.96 T) low iron loss is achieved without providing magnetic domain-refining treatment, very low iron loss value by forming grooves on the steel sheet surface, smoothening the steel sheet surface or a combination thereof.
    Type: Grant
    Filed: July 16, 1998
    Date of Patent: August 29, 2000
    Assignee: Kawasaki Steel Corporation
    Inventors: Kunihiro Senda, Toshito Takamiya, Michiro Komatsubara
  • Patent number: 6103022
    Abstract: In a grain oriented electrical steel sheet used for cores of transformers and generators, a high alignment degree of grain orientations reduces iron loss, by precipitating very fine AlN or/and BN and providing strong inhibiting effect against the growth of the primary recrystallized grains, providing radically improved texture and grain structure in the steel.
    Type: Grant
    Filed: March 24, 1998
    Date of Patent: August 15, 2000
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Toshito Takamiya, Kunihiro Senda
  • Patent number: 6083326
    Abstract: A grain-oriented electromagnetic steel sheet having a multiplicity of fine grains having a diameter of about 3 mm or less on the surface of the steel sheet, in a numerical ratio of about 65% or more and of about 98% or less relative to the constituting grains that penetrate the sheet along the direction parallel to its thickness, and a method for producing the same. The fine grains are artificially created and regularly disposed with a random orientation in the steel sheet, and contribute to decreasing the strain susceptibility of the steel. More preferably, a treatment for finely dividing magnetic domains is applied on the surface of the steel sheet. Transformers based upon the steel sheet have excellent magnetic characteristics (iron loss and magnetic flux density) together with strain resistance, and the steel sheet has good practical device characteristics (building factor) after being assembled into a transformer.
    Type: Grant
    Filed: October 20, 1997
    Date of Patent: July 4, 2000
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Toshito Takamiya, Kunihiro Senda
  • Patent number: 6039818
    Abstract: A grain-oriented electromagnetic steel sheet is provided which has a low ratio of iron loss in a weaker magnetic field to that in a stronger magnetic field and has special advantage in EI cores and the like. Also provided is a process for producing that steel sheet. The grain-oriented electromagnetic steel sheet is characterized in that its crystal grains of important components are specified in terms of their proportions in number, and the contents of Al, Ti and B, with a forsterite film formed on a surface of the steel sheet. In the process a low-Al silicon slab is heated at below 1,250.degree. C. before hot rolling and the hot-rolled sheet is annealed with a temperature rise in the range of from 5 to 25.degree. C./sec and at a temperature of from about 800 to 1,000 for a period of time of shorter than about 100 seconds.
    Type: Grant
    Filed: October 20, 1997
    Date of Patent: March 21, 2000
    Assignee: Kawasaki Steel Corporation
    Inventors: Tetsuo Toge, Michiro Komatsubara, Atsuhito Honda, Kenichi Sadahiro, Kunihiro Senda
  • Patent number: 5885371
    Abstract: A method of producing a grain-oriented magnetic steel sheet exhibiting a very low core loss and high magnetic flux density uses a slab of silicon steel containing Al, B, N, and S and/or Se. The method employs hot rolling conducted such that the rolling reduction falls within the range of from about 85 to 99%, and the hot-rolling finish temperature falls within the range of from 950.degree. to 1150.degree. C. and is based on the contents of Si, Al and B. The hot-rolled steel sheet is rapidly cooled at a cooling rate of about 20.degree. C./s and is coiled at a temperature of about 670.degree. C. or lower. Hot-rolled sheet annealing or intermediate annealing is executed by heating the hot-rolled steel sheet up to about 800.degree. C. at a heating rate of from 5.degree. to 25.degree. C./s and holding at a temperature of from about 800.degree. to 1125.degree. C. for a period not longer than about 150 seconds.
    Type: Grant
    Filed: October 9, 1997
    Date of Patent: March 23, 1999
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Toshito Takamiya, Kunihiro Senda, Mineo Muraki, Chizuko Goto, Mitsumasa Kurosawa, Kazuaki Tamura
  • Patent number: 5853499
    Abstract: Grain-oriented electrical steel sheet having a very low iron loss with controlled area ratio of fine grains, average grain size of coarse grains, obliquity of the grain boundary line of coarse grains, permeability under 1.0 T, and film tension.
    Type: Grant
    Filed: August 28, 1997
    Date of Patent: December 29, 1998
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Kunihiro Senda, Takafumi Suzuki, Hiroaki Toda, Hiroi Yamaguchi
  • Patent number: 5718775
    Abstract: Grain-oriented electrical steel sheet having a very low iron loss with controlled area ratio of fine grains, average grain size of coarse grains, obliquity of the grain boundary line of coarse grains, permeability under 1.0 T, and film tension.
    Type: Grant
    Filed: November 25, 1996
    Date of Patent: February 17, 1998
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Kunihiro Senda, Takafumi Suzuki, Hiroaki Toda, Hiroi Yamaguchi
  • Patent number: 5665455
    Abstract: A low-iron-loss grain-oriented electromagnetic steel sheet is provided with the multiplicity of linear grooves formed in a surface thereof to extend in a direction substantially perpendicular to the direction of rolling of the steel sheet at a predetermined pitch in the direction of rolling, and a multiplicity of linear high dislocation density regions introduced to extend in a direction substantially perpendicular to the direction of rolling of the steel sheet at a predetermined pitch in the direction of rolling. The pitches l.sub.1 and l.sub.
    Type: Grant
    Filed: April 26, 1996
    Date of Patent: September 9, 1997
    Assignee: Kawasaki Steel Corporation
    Inventors: Seiji Sato, Masayoshi Ishida, Kunihiro Senda, Kazuhiro Suzuki, Michiro Komatubara
  • Patent number: 5665178
    Abstract: A method of manufacturing a grain-oriented silicon steel sheet having excellent and stable magnetic characteristics which includes the steps of subjecting a silicon steel slab to hot rolling to form a hot-rolled sheet, cold rolling the hot-rolled sheet at least once with intermediate annealings between successive cold rollings to form a cold-roiled sheet, and thereafter primary recrystallization annealing the cold-rolled sheet to form a primary recrystallized sheet. The primary recrystallized sheet is then final finish annealed, which includes a secondary recrystallization annealing and a purifying annealing during which the steel slab is coated with an annealing separator. The coercive force of the primary recrystallized steel sheet is controlled to a predetermined range before the start of secondary recrystallization.
    Type: Grant
    Filed: February 5, 1996
    Date of Patent: September 9, 1997
    Assignee: Kawasaki Steel Corporation
    Inventors: Michiro Komatsubara, Masayoshi Ishida, Kunihiro Senda