Patents by Inventor Hiroshi Ohtsubo
Hiroshi Ohtsubo 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).
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Patent number: 5939018Abstract: Martensitic stainless steels that enable the fabrication of high-strength seamless steel pipe suited for use in oil-well pipe and pipeline tubing by means of a Mannesmann plug mill or Mannesmann mandrel mill process, without the formation of defects during production. The heat workability of these steels, which contain no more than 0.30% by weight of carbon and from 11 to 14% by weight of chromium, and have a ferrite content of at least 40% at 1200.degree. C., has been vastly improved by holding the phosphorus and sulfur levels therein to no more than 0.020% and 0.003% by weight, respectively.Type: GrantFiled: November 29, 1996Date of Patent: August 17, 1999Assignee: Kawasaki Steel CorporationInventors: Hiroshi Ohtsubo, Tatsuo Kawasaki, Isao Takada
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Patent number: 5773099Abstract: A dental care material comprising a titanium sintered body has no harmful effects on the human body and easily produces products with complicated shapes having a high level of strength. A mixture of titanium powder and an organic binder is injection molded and subjected to binder removal and sintering processes to form a bracket for orthodontic or dental implant materials. Pure titanium powder, with an average granule diameter of no more than 40 .mu.m, a carbon content by weight of no more than 0.3%, and an oxygen content by weight of no more than 0.6%, preferably is used to produce a titanium sintered body of combined carbon and oxygen content by weight of no more than 1.0%. Colored layers can be formed on the surface of the titanium sintered body using various methods as needed.Type: GrantFiled: April 25, 1996Date of Patent: June 30, 1998Assignees: Injex Corporation, Matsumoto Dental CollegeInventors: Naoki Tanaka, Hiroshi Ohtsubo, Michio Ito
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Patent number: 5613849Abstract: A dental care material comprising a titanium sintered body has no harmful effects on the human body and easily produces products with complicated shapes having a high level of strength. A mixture of titanium powder and an organic binder is injection molded and subjected to binder removal and sintering processes to form a bracket for orthodontic or dental implant materials. Pure titanium powder, with an average granule diameter of no more than 40 .mu.m, a carbon content by weight of no more than 0.3%, and an oxygen content by weight of no more than 0.6%, preferably is used to produce a titanium sintered body of combined carbon and oxygen content by weight of no more than 1.0%. Colored layers can be formed on the surface of the titanium sintered body using various methods as needed.Type: GrantFiled: January 25, 1995Date of Patent: March 25, 1997Assignees: Injex Corporation, Matsumoto Dental CollegeInventors: Naoki Tanaka, Hiroshi Ohtsubo, Michio Ito
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Patent number: 5507853Abstract: This invention is to control the diffusion of C (carbon) from added graphite to particles of iron powder in the sintering to thereby improve the accuracy of dimensional change in the sintered body by using iron powder for powder metallurgy and a mixed powder thereof as a starting material in the production of sintered mechanical parts by adding the iron powder with Cu powder and graphite powder and companying and sintering them, in which 0.008-0.5 wt % in total of at least one element having a value of standard free energy of formation of oxide at 1000.degree. C. of not more than -120 kcal/l mol of O.sub.2 is included in the iron powder and not less than 20% of the element is rendered into an oxide, or 0.01-0.20 wt % in total of an oxide powder of at least one element having a value of standard free energy of formation of oxide at 1000.degree. C. of not more than -120 kcal/l mol of O.sub.2 is added to the mixed powder.Type: GrantFiled: June 1, 1995Date of Patent: April 16, 1996Assignee: Kawasaki Steel CorporationInventors: Kuniaki Ogura, Hiroyuki Ishikawa, Takeo Omura, Yoshiaki Maeda, Minoru Nitta, Hiroshi Ohtsubo, Yutyaka Yoshii
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Patent number: 5458670Abstract: This invention is to control the diffusion of C (carbon) from added graphite to particles of iron powder in the sintering to thereby improve the accuracy of dimensional change in the sintered body by using iron powder for powder metallurgy and a mixed powder thereof as a starting material in the production of sintered mechanical parts by adding the iron powder with Cu powder and graphite powder and companying and sintering them, in which 0.008-0.5 wt % in total of at least one element having a value of standard free energy of formation of oxide at 1000.degree. C. of not more than -120 kcal/1 mol of O.sub.2 is included in the iron powder and not less than 20% of the element is rendered into an oxide, or 0.01-0.20 wt % in total of an oxide powder of at least one element having a value of standard free energy of formation of oxide at 1000.degree. C. of not more than -120 kcal/1 mol of O.sub.2 is added to the mixed powder.Type: GrantFiled: May 2, 1994Date of Patent: October 17, 1995Assignee: Kawasaki Steel CorporationInventors: Kuniaki Ogura, Hiroyuki Ishikawa, Takeo Omura, Yoshiaki Maeda, Minoru Nitta, Hiroshi Ohtsubo, Yutaka Yoshii
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Patent number: 5380476Abstract: A debinding method for use in a process for producing a sintered object, by effecting a debinding pre-treatment by heating the injection-molded object in an atmosphere of reduced pressure at a temperature at which the vapor pressure of the component of the organic binder having the highest vapor pressure does not exceed the pressure of the atmosphere, thereby removing the organic binder in the amount of at least about 18 wt %; and effecting a further debinding heat treatment in which the injection-molded object is heated to and maintained at a temperature higher than the temperature in the debinding pre-treatment.Type: GrantFiled: September 16, 1991Date of Patent: January 10, 1995Assignee: Kawasaki Steel CorporationInventors: Masakazu Matsushita, Yoshisato Kiyota, Hiroshi Ohtsubo, Junichi Ohta
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Patent number: 5338508Abstract: There is provided alloy steel powders for the injection molding use manufactured by the atomizing method which are characterized by their substantially spherical particle shape and average particle diameters of 20 microns or less, a compound for the injection molding use which contains the alloy steel powders and one or more organic binders, a process for manufacturing sintered materials in performing injection molding of compound and subsequently debinding the obtained injection molded part followed by sintering the debound part, at least the first stage of the sintering step is performed in reduced pressure atmosphere, and the sintered material having a relative density ratio of 92% or more.Type: GrantFiled: October 16, 1992Date of Patent: August 16, 1994Assignee: Kawasaki Steel CorporationInventors: Minoru Nitta, Yoshisato Kiyota, Yukio Makiishi, Hiroshi Ohtsubo, Toshio Watanabe, Yasuhiro Habu
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Patent number: 5108492Abstract: It is provided a method for the manufacture of a corrosion-resistant sintered alloy steel, which comprises providing a stainless steel powder; adding a binder to said steel powder; molding the mixture; and carrying out the steps of (1) heating the resultant molding to remove the binder therefrom, (2) sintering the thus debound molding under reduced pressure up to 30 Torr, and (3) further sintering at a higher temperature than those of steps (1) and (2) in a non-oxidative atmosphere under substantially atmospheric pressure. It is also provided a corrosion-resistant sintered alloy steel which comprises a stainless steel, said alloy steel having a density ratio of not less than 92%, a maximum diametric of pore present in the structure of not larger than 20 .mu.m, and a content of Cr at the surface of the steel as being sintered which is not less than 80% of a content of Cr in the inside thereof.Type: GrantFiled: February 22, 1990Date of Patent: April 28, 1992Assignee: Kawasaki Steel CorporationInventors: Yoshisato Kiyota, Hiroshi Ohtsubo, Junichi Ohta, Masakazu Matsushita, Ichio Sakurada
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Patent number: 5067979Abstract: A process is provided for the production of a sintered body. The process includes the following consecutive steps: i) mixing and kneading one or more metal powders and/or one or more alloy powder with a binder into a compound, said metal and alloy powders having an average particle size not greater than 30 .mu.m, ii) injection-molding the compound into a green body; iii) debinding the green body to form a debound body; and iv) subjecting the debound body to a first-stage sintering at 1,050.degree.-1,250.degree. C. in a reduced-pressure atmosphere and then to second-stage sintering at a temperature in a range of 1,100.degree.-400.degree. C. which is higher than that of the first-stage sintering. This process can provide sintered Ti bodies and sintered magnetic bodies of the Fe-Si type, which have a density ratio of at least 95%.Type: GrantFiled: July 6, 1990Date of Patent: November 26, 1991Assignee: Kawasaki Steel CorporationInventors: Yoshisato Kiyota, Junichi Ohta, Hiroshi Ohtsubo, Shigeaki Takajo
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Patent number: 5033036Abstract: A reproducing apparatus mixes the voice information from a microphone and the information reproduced from a recording medium in which a vocal signal plus an instrumental signal is contained as a first signal in a first channel and only an instrumental signal is contained as a second signal in a second channel. A first mixing circuit mixes the first signal and the second signal. The output of the first mixing circuit is mixed by a second mixing circuit with the voice information from the microphone. A control circuit or audio detecting circuit provides a control signal in accordance with the level of the voice information from the microphone. The control signal controls a selection control circuit to gradually and smoothly vary the mixing ratio of the first signal and the second signal when mixing these two signals.Type: GrantFiled: January 23, 1990Date of Patent: July 16, 1991Assignee: Pioneer Electronic CorporationInventors: Seiji Ohmori, Eisaku Kawano, Tasuku Tsuruga, Takeshi Mawatari, Hiroshi Ohtsubo
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Patent number: 4971755Abstract: It is disclosed a method for preparing a large-sized powder metallurgical sintered product having a superior characteristic by charging mixtures of three types of metallic powder composed of coarse particles, middle particles and fine particles into the molding die while vibrating it, heating the charged material together with the molding die, sintering them, and infiltrating metal of low melting point into the sintered body. According to this method, it is possible to get a large-sized sintered body having a superior strength and surface smoothness or a sintered body prohibiting any cracks or slits by arranging the proper particle size.Type: GrantFiled: June 20, 1989Date of Patent: November 20, 1990Assignee: Kawasaki Steel CorporationInventors: Masaki Kawano, Kuniaki Ogura, Shigeaki Takajo, Hiroshi Ohtsubo, Keisuke Yoshimura, Yoshiaki Maeda
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Patent number: 4964907Abstract: A process is provided for the production of a sintered body. The process includes the following consecutive steps: (i) mixing and kneading one or more metal powders and/or one or more alloy powder with a binder into a compound, said metal and alloy powders having an average particle size not greater than 30 .mu.m, (ii) injection-molding the compound into a green body; (iii) debinding the green body to form a debound body; and (iv) subjecting the debound body to first-stage sintering at 1,050.degree.-1,250.degree. C. in a reducing or reduced-pressure atmosphere and then to second-stage sintering at a temperature in a range of 1,100.degree.-1,400.degree. C. which is higher than that of the first-stage sintering. This process can provide sintered Ti bodies and sintered magnetic bodies of the Fe-Si type, which have a density ratio of at least 95%.Type: GrantFiled: August 14, 1989Date of Patent: October 23, 1990Assignee: Kawasaki Steel Corp.Inventors: Yoshisato Kiyota, Junichi Ohta, Hiroshi Ohtsubo, Shigeaki Takajo
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Patent number: 4604887Abstract: A duplex stainless steel seamless pipe can be inexpensively produced in high productivity and yield without causing cracks during the working steps in the plug mill process by a proper combination of the composition of the steel and the working conditions of a billet and a hollow piece for the production of the pipe.Type: GrantFiled: November 30, 1984Date of Patent: August 12, 1986Assignee: Kawasaki Steel CorporationInventors: Hiroshi Ohtsubo, Isao Takada, Tatsuo Kawasaki
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Patent number: 4533806Abstract: A method of manufacturing bimetallic tubes is disclosed. In this method, after an inner tube is inserted into an outer tube, the resulting tube assembly is heated, while pressurizing the inside of the inner tube with a gas, in the presence or absence of a solder material. When using no solder material, the materials of the inner and outer tubes are so selected that a thermal expansion coefficient of the inner tube is smaller than that of the outer tube.Type: GrantFiled: June 1, 1982Date of Patent: August 6, 1985Assignee: Kawasaki Steel CorporationInventors: Tatsuo Kawasaki, Isao Takada, Hiroshi Ohtsubo