Patents by Inventor Takatoshi Yoshioka
Takatoshi Yoshioka 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: 4585478Abstract: A heat resisting steel suitable for use as the materials of steam turbine casings of steam turbines for thermal power generation. The steel has a composition consisting essentially of 0.05 to 0.2 wt % of C, 0.5 to 2.0 wt % of Cr, 0.5 to 2.0 wt % of Mo, 0.05 to 0.5 wt % of V, 0.002 to 0.1 wt % of Al, 0.0002 to 0.0030 wt % of B and the balance substantially Fe and inevitable impurities, wherein the sum of X and Al as obtained from the following formulae is not greater than 2920:X=10P+5Sb+4Sn+AsAl=xAl(x being a coefficient obtained from FIG. 4)where, P,Sb,Sn and As represent the contents of P,Sb,Sn and As contained as said inevitable impurities in terms of ppm, while Al represents the Al content in terms of ppm. This heat resisting steel exhibits a large resistance to cracking in stress relief annealing after welding, as well as a high creep rupture strength at high temperature, and shows only a low crack developing speed.Type: GrantFiled: May 4, 1984Date of Patent: April 29, 1986Assignee: Hitachi, Ltd.Inventors: Takatoshi Yoshioka, Seishin Kirihara, Masao Siga, Mitsuo Kuriyama, Takehiko Yoshida, Takanori Murohoshi
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Patent number: 4581067Abstract: A high-strength austenitic steel having a fully austenite structure and consisting essentially of 0.02 to 0.15 wt % of C, not greater than 1.5 wt % of Si, not greater than 2.5 wt % of Mn, 8 to 20 wt % of Ni, 13 to 25 wt % of Cr, 0.02 to 0.25 wt % of Al, not greater than 0.1 wt % of N, at least one of 0.001 to 0.01 wt % of B, 0.02 to 0.5 wt % of Nb, 0.01 to 0.2 wt % of Ti and 0.02 to 0.6 wt % of V and the balance substantialy Fe, with the weight ratio (Al/N) ranging between 1 and 4.5. This steel is suitable for use as the material of, for example, inner casing of steam turbine, valve body incorporated in the steam turbine, rotor shaft, and chemical equipment such as reaction pipe and vessel for styrene monomer producing facility.Type: GrantFiled: November 1, 1983Date of Patent: April 8, 1986Assignee: Hitachi, Ltd.Inventors: Katsumi Iijima, Norio Yamada, Seishin Kirihara, Masao Shiga, Masayuki Sukekawa, Takatoshi Yoshioka, Kiyoshi Hiyama
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Patent number: 4566810Abstract: A steam turbine rotor shaft made of precipitation-hardened forged austenite steel, comprising first, second and succeeding layers of build-up welding provided on an outer surface of a bearing portion of a journal section in the rotor shaft, the first layer being provided by use of a welding rod of Ni base alloy, the second and succeeding layers being provided by use of a welding rod of low alloy steel which layers have better bearing characteristics than those of the austenite steel.Type: GrantFiled: April 12, 1983Date of Patent: January 28, 1986Assignee: Hitachi, Ltd.Inventors: Takatoshi Yoshioka, Seishin Kirihara, Masao Shiga, Katsumi Iijima, Katsukuni Hisano, Ryoichi Kaneko
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Patent number: 4504554Abstract: A steam turbine rotor shaft comprising the main body of the rotor shaft made of a high Cr steel of martensite structure, and a journal having a plurality of built-up welding layers formed successively said main body, the outer surface portion of the journal being made of steel containing 0.5 to 3 wt % of Cr, and a method of producing same.Type: GrantFiled: March 30, 1982Date of Patent: March 12, 1985Assignee: Hitachi, Ltd.Inventors: Takatoshi Yoshioka, Seishin Kirihara, Masao Siga, Takehiko Yoshida, Katsukuni Hisano, Toshimi Tan, Masahiro Kobayashi
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Patent number: 4497670Abstract: A rotor shaft for steam turbines has a journal portion to be supported by a bearing. The journal portion is provided with a sleeve for a bearing made of an alloy of bainite structure comprising 0.04 to 0.35% C, 0.2 to 2% Mn, less than 1% Si, 0.5 to 3% Cr, less than 5% Ni, and less than 0.5% V, having yield strength of more than 50 kg/mm.sup.2 and Lt of less than 24. The sleeve is divided into two semicylindrical segments, and they are arranged on a small diameter portion of the shaft adjacent to said journal portion, welded into one piece, and subjected to stress relief treatment at a temperature higher than a temperature of tempering conducted to the sleeve before welding. The welded sleeve is fitted on the journal portion by shrink-fit so that the sleeve can be served as a superior bearing.Type: GrantFiled: February 4, 1983Date of Patent: February 5, 1985Assignee: Hitachi, Ltd.Inventors: Masao Siga, Seishin Kirihara, Takatoshi Yoshioka, Katsukuni Hisano, Toshimi Tan, Yoji Akutsu, Kei Kobayashi
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Patent number: 4477280Abstract: A heat resisting steel suitable for use as material of steam turbine parts. The steel has a substantially whole tempered martensite structure and consisting essentially of, by weight, 8 to 13% of Cr, 0.5 to 2% of Mo, 0.02 to 0.5% of V, 0.02 to 0.15% of Nb, 0.025 to 0.1% of N, 0.05 to 0.25% of C, not greater than 0.6% of Si, not greater than 1.5% of Mn, not greater than 1.5% of Ni, 0.0005 to 0.02% of Al, 0.1 to 0.5% of W and the balance substantially Fe, the ratio W/Al between W content and Al content ranging between 10 and 110.Type: GrantFiled: December 22, 1982Date of Patent: October 16, 1984Assignee: Hitachi, Ltd.Inventors: Masao Shiga, Seishin Kirihara, Mitsuo Kuriyama, Takatoshi Yoshioka, Ryoichi Sasaki
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Patent number: 4426162Abstract: A rotor shaft suitable for use as the rotor shaft of a steam turbine. The rotor shaft has a rotor shaft portion made of a Cr alloy steel having martensite structure and containing 8 to 13% Cr. The rotor shaft body is provided with at least one journal portion at which the rotor shaft is rotatably supported by a bearing. The rotor shaft further has a sleeve fitted around each journal portion. The sleeve is divided in the circumferential direction into a plurality of segments which are assembled together by welding or fitting into the sleeve having a circular cross-section. Due to the provision of the sleeve around the journal portion, the rotor shaft made of Cr alloy steel can have improved bearing properties.Type: GrantFiled: December 1, 1981Date of Patent: January 17, 1984Assignee: Hitachi, Ltd.Inventors: Keiichi Tsuchiya, Katsukuni Hisano, Toshimi Tan, Masahiro Kobayashi, Kei Kobayashi, Kazuhiko Ueda, Seishin Kirihara, Takatoshi Yoshioka, Masao Shiga