Patents by Inventor Masahiko Arai
Masahiko Arai 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: 10378366Abstract: A steam turbine rotor blade achieving both abrasion resistance and reliability, and a method for manufacturing a steam turbine rotor blade capable of obtaining such a steam turbine rotor blade are provided. A steam turbine rotor blade according to the invention is characterized by including a blade base material and an erosion shield formed on a surface of the blade base material, wherein the blade base material is composed of a titanium alloy, and the erosion shield is composed of a weld overlay layer including a parent phase composed of pure titanium in which a metal element is solid-dissolved or a titanium alloy in which a metal element is solid-dissolved, and a hard phase dispersed in the parent phase.Type: GrantFiled: April 11, 2016Date of Patent: August 13, 2019Assignee: MITSUBISHI HITACHI POWER SYSTEMS, LTD.Inventors: Shinji Oikawa, Masahiko Arai, Hiroyuki Doi, Hideo Yoda
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Publication number: 20180080329Abstract: A steam turbine rotor blade achieving both abrasion resistance and reliability, and a method for manufacturing a steam turbine rotor blade capable of obtaining such a steam turbine rotor blade are provided. A steam turbine rotor blade according to the invention is characterized by including a blade base material and an erosion shield formed on a surface of the blade base material, wherein the blade base material is composed of a titanium alloy, and the erosion shield is composed of a weld overlay layer including a parent phase composed of pure titanium in which a metal element is solid-dissolved or a titanium alloy in which a metal element is solid-dissolved, and a hard phase dispersed in the parent phase.Type: ApplicationFiled: April 11, 2016Publication date: March 22, 2018Applicant: MITSUBISHI HITACHI POWER SYSTEMS, LTD.Inventors: Shinji OIKAWA, Masahiko ARAI, Hiroyuki DOI, Hideo YODA
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Patent number: 9873930Abstract: It is an objective of the present invention to provide a precipitation-hardening martensitic stainless steel having well-balanced properties of high mechanical strength, high toughness and good corrosion resistance properties. There is provided a precipitation-hardening martensitic stainless steel comprising: 0.10 mass % or less of C; 13.0 to 15.0 mass % of Cr; 7.0 to 10.0 mass % of Ni; 2.0 to 3.0 mass % of Mo; 0.5 to 2.5 mass % of Ti; 0.5 to 2.5 mass % of Al; 0.5 mass % or less of Si; 0.1 to 1.0 mass % of Mn; and the balance including Fe and incidental impurities, in which the mass % content of the Ti (represented by [Ti content]), the mass % content of the Al (represented by [Al content]) and the mass % content of the C (represented by [C content]) satisfy relationships of “0.5?[Ti content]?2.5” and “0.5?[Al content]+2[C content]?2.7”.Type: GrantFiled: November 9, 2011Date of Patent: January 23, 2018Assignee: Mitsubishi Hitachi Power Systems, Ltd.Inventors: Shinji Oikawa, Hideo Yoda, Masahiko Arai, Hiroyuki Doi
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Patent number: 9784110Abstract: It is an objective of the invention to provide a steam turbine rotor that is capable of both reducing SCC susceptibility and improving LCF life thereof. There is provided a steam turbine rotor, comprising a rotor disk in a low pressure final stage L-0, and another rotor disk in a plurality of stages including a stage L-1 positioned closer to a high pressure side than the low pressure final stage L-0, the rotor disk in the low pressure final stage L-0 and the rotor disk in a plurality of stages including the stage L-1 being joined by welding, wherein a material of both the rotor disk in the low pressure final stage L-0 and the rotor disk in a plurality of stages including the stage L-1 is a 12Cr steel and has a tensile strength of 900 to 1200 MPa.Type: GrantFiled: August 7, 2014Date of Patent: October 10, 2017Assignee: Mitsubishi Hitachi Power Systems, Ltd.Inventors: Kunio Asai, Masahiko Arai, Kenichi Murata
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Patent number: 9388702Abstract: The problem to be solved of the present invention is to provide a precipitation hardening martensitic stainless steel having excellent tissue stability, strength, toughness, and corrosion-resistance, requiring no sub-zero treatment, and having excellent productivity; and also a steam turbine long blade using the same. The problem is solved by providing a precipitation hardening martensitic stainless steel containing, by mass, 0.1% or less of C; 0.1% or less of N; 9.0% or more and 14.0% or less of Cr; 9.0% or more and 14.0% or less of Ni; 0.5% or more and 2.5% or less of Mo; 0.5% or less of Si; 1.0% or less of Mn; 0.25% or more and 1.75% or less of Ti; 0.25% or more and 1.75% or less of Al, and the rest is Fe and inevitable impurities; and a steam turbine long blade using the precipitation hardening martensitic stainless steel.Type: GrantFiled: January 15, 2013Date of Patent: July 12, 2016Assignee: MITSUBISHI HITACHI POWER SYSTEMS, LTD.Inventors: Shinji Oikawa, Hideo Yoda, Masahiko Arai, Hiroyuki Doi
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Publication number: 20160108743Abstract: Disclosed is a turbine blade including a turbine blade substrate including an iron-base alloy; an erosion shield plate including a Co-base alloy; and a shim including a Ni—Fe alloy, in which the erosion shield plate is fixed to a leading edge of the turbine blade substrate with the shim therebetween by an electron beam welding. Thus, a turbine blade having a highly reliable, bonded portion of an erosion shield, and a turbine rotor and a steam turbine using the turbine blade are provided.Type: ApplicationFiled: December 31, 2015Publication date: April 21, 2016Inventors: Masahiko ARAI, Hiroyuki DOI, Hideo YODA, Katsumi TANAKA
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Patent number: 9200524Abstract: There is provided a steam turbine rotor with high reliability and corresponding to increase in length of a high strength steel blade, in which only a low-pressure last stage is highly strengthened. The steam turbine rotor includes a steam turbine low-pressure last stage long blade made of a precipitation hardening type martensitic stainless steel containing, in mass, 0.1% or less of C, 0.1% or less of N, 9.0% to 14.0% inclusive of Cr, 9.0% to 14.0% inclusive of Ni, 0.5% to 2.5% inclusive of Mo, 0.5% or less of Si, 1.0% or less of Mn, 0.25% to 1.75% inclusive of Ti, 0.25% to 1.75% inclusive of Al, and the balance consisting of Fe and inevitable impurities, and a disk having a specific alloy composition is joined to a last stage section of the turbine rotor made of a low-alloy steel.Type: GrantFiled: February 26, 2013Date of Patent: December 1, 2015Assignee: Mitsubishi Hitachi Power Systems, Ltd.Inventors: Masahiko Arai, Hiroyuki Doi, Shinji Oikawa, Kenichi Murata
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Patent number: 9062362Abstract: As a precipitate hardening stainless steel has excellent structure stability, strength, toughness, and corrosion resistance, requires no sub-zero treating and is excellent in terms of productivity, a long blade for a steam turbine uses the same. The following are provided: a precipitate hardening stainless steel, which comprises C at 0.05 mass % or less, N at 0.05 mass % or less, Cr at 10.0 mass % to 14.0 mass %, Ni at 8.5 mass % to 11.5 mass %, Mo at 0.5 mass % to 3.0 mass %, Ti at 1.5 mass % to 2.0 mass %, Al at 0.25 mass % to 1.00 mass %, Si at 0.5 mass % or less, and Mn at 1.0 mass % or less, and the balance is composed of Fe and inevitable impurities. The long blade for a steam turbine is composed of this precipitate hardening stainless steel.Type: GrantFiled: June 13, 2012Date of Patent: June 23, 2015Assignee: Mitsubishi Hitachi Power Systems, Ltd.Inventors: Shinji Oikawa, Hideo Yoda, Masahiko Arai, Hiroyuki Doi
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Patent number: 8962613Abstract: A diazepine derivative having the following formula (III) or a pharmacologically acceptable salt thereof is used as A P2X4 receptor antagonist: wherein each of R21 and R22 is hydrogen, a C1-8 alkyl group or the like; R23 is hydrogen, a C1-8 alkyl group or the like; each of R24 and R25 is hydrogen, a C1-8 alkyl group or the like; R26 is hydrogen, a C1-8 alkyl group, a halogen atom, hydroxyl, nitro, cyano, phenyl optionally having one or more substituents, or a heterocyclic group optionally having one or more substituents or the like; and p is 0 or 1.Type: GrantFiled: July 13, 2011Date of Patent: February 24, 2015Assignee: Nippon Chemiphar Co., Ltd.Inventors: Shogo Sakuma, Masahiko Arai, Kunio Kobayashi, Yoshikazu Watanabe, Toshiyasu Imai, Kazuhide Inoue
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Publication number: 20150044053Abstract: It is an objective of the invention to provide a steam turbine rotor that is capable of both reducing SCC susceptibility and improving LCF life thereof. There is provided a steam turbine rotor, comprising a rotor disk in a low pressure final stage L-0, and another rotor disk in a plurality of stages including a stage L-1 positioned closer to a high pressure side than the low pressure final stage L-0, the rotor disk in the low pressure final stage L-0 and the rotor disk in a plurality of stages including the stage L-1 being joined by welding, wherein a material of both the rotor disk in the low pressure final stage L-0 and the rotor disk in a plurality of stages including the stage L-1 is a 12Cr steel and has a tensile strength of 900 to 1200 MPa.Type: ApplicationFiled: August 7, 2014Publication date: February 12, 2015Inventors: Kunio ASAI, Masahiko ARAI, Kenichi MURATA
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Publication number: 20140379280Abstract: A remaining life assessment method for a heat-resisting steel member to be used under a high temperature includes the steps of: determining a hardness of each of a simply heated material and a damaged portion from creep rupture tests and creep interruption tests of a heat-resisting steel material constituting the heat-resisting steel member under conditions of various heating temperatures, loaded stresses and heating periods, calculating a damage rate and a time-temperature parameter, and obtaining a relationship between the hardness of each of the simply heated material and the damaged portion, and the damage rate or the time temperature parameter; calculating a difference between the hardness of the simply heated material and the hardness of the damaged portion, and obtaining a relationship between the difference and the damage rate; measuring an initial hardness in an unused state of the heat-resisting steel member to be assembled into an actual machine; calculating an initial value of the time-temperatureType: ApplicationFiled: June 19, 2014Publication date: December 25, 2014Inventors: Masahiko ARAI, Hiroyuki DOI, Shinichi KOBAYASHI, Kenichi MURATA
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Patent number: 8747733Abstract: A precipitation hardenable martensitic stainless steel excellent in the stability of martensite, having the high strength, high toughness and high corrosion resistance is provided. The precipitation hardenable martensitic stainless steel contains at a mass rate, C: 0.05-0.10%, Cr: 12.0-13.0%, Ni: 6.0-7.0%, Mo: 1.0-2.0%, Si: 0.01-0.05%, Mn: 0.06-1.0%, Nb: 0.3-0.5%, V: 0.3-0.5%, Ti: 1.5-2.5%, Al: 1.0-2.3%, and the remainder consisting of Fe and an unavoidable impurity.Type: GrantFiled: April 14, 2011Date of Patent: June 10, 2014Assignee: Hitachi, Ltd.Inventors: Shinji Oikawa, Hideo Yoda, Masahiko Arai, Hiroyuki Doi
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Publication number: 20140105753Abstract: A precipitation hardening martensitic stainless steel is provided with excellent mechanical property and corrosion resistance and contains, by mass, 0.1% or less of C; 0.1% or less of N; 10.0%˜15.0% of Cr; 10.0%˜15.0% of Ni; 0.5%˜2.5% of Mo; 1.0%˜3.0% of Al; 1.0% or less of Si; 1.0% or less of Mn, and the rest is Fe and inevitable impurities. A steam turbine long blade is made of the precipitation hardening martensitic stainless steel.Type: ApplicationFiled: October 10, 2013Publication date: April 17, 2014Applicant: Hitachi, Ltd.Inventors: Shinji OIKAWA, Hideo YODA, Masahiko ARAI, Hiroyuki DOI
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Patent number: 8596982Abstract: A turbine rotor which is easy to manufacture and has a high tolerable temperature is provided. A highly efficient steam turbine power plant is also provided. The turbine rotor is configured from a rotor shaft, an inner rotor disc constructed integrally with the rotor shaft, and an outer rotor disc which is welded to the inner rotor disc via a weld metal part and has a structure for fixing a turbine blade. The outer rotor disc preferably has a cooling hole which extends in an axial direction to penetrate the outer rotor disc over the thickness of the outer rotor disc.Type: GrantFiled: June 23, 2010Date of Patent: December 3, 2013Assignee: Hitachi, Ltd.Inventors: Eiji Nishioka, Masahiko Arai, Hiroyuki Doi
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Patent number: 8485788Abstract: A steam turbine rotor shaft and method of manufacturing the same are provided wherein the sliding characteristics of a journal are improved, and the journal is free from welding cracks and does not need a post heat treatment. The low alloy steel coating layer having better sliding characteristics than 9 to 13% Cr heat resisting steel and an area rate of defects including pores and oxides in a range of 3 to 15% is formed by a high velocity flame spray coating method on a sliding surface of the journal.Type: GrantFiled: June 9, 2006Date of Patent: July 16, 2013Assignee: Hitachi, Ltd.Inventors: Hideyuki Arikawa, Akira Mebata, Masahiko Arai, Yoshitaka Kojima, Haijime Toriya
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Publication number: 20130172550Abstract: A diazepine derivative having the following formula (III) or a pharmacologically acceptable salt thereof is used as A P2X4 receptor antagonist: wherein each of R21 and R22 is hydrogen, a C1-8 alkyl group or the like; R23 is hydrogen, a C1-8 alkyl group or the like; each of R24 and R25 is hydrogen, a C1-8 alkyl group or the like; R26 is hydrogen, a C1-8 alkyl group, a halogen atom, hydroxyl, nitro, cyano, phenyl optionally having one or more substituents, or a heterocyclic group optionally having one or more substituents or the like; and p is 0 or 1.Type: ApplicationFiled: July 13, 2011Publication date: July 4, 2013Applicant: Nippon Chemiphar Co., Ltd.Inventors: Shogo Sakuma, Masahiko Arai, Kunio Kobayashi, Yoshikazu Watanabe, Toshiyasu Imai, Kazuhide Inoue
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Publication number: 20120321478Abstract: This invention provides a precipitate hardening stainless steel having excellent structure stability, strength, toughness, and corrosion resistance, which requires no sub-zero treating and thus is excellent in terms of productivity, and a long blade for a steam turbine using the same. The following are provided: a precipitate hardening stainless steel, which comprises C at 0.05 mass % or less, N at 0.05 mass % or less, Cr at 10.0 mass % to 14.0 mass %, Ni at 8.5 mass % to 11.5 mass %, Mo at 0.5 mass % to 3.0 mass %, Ti at 1.5 mass % to 2.0 mass %, Al at 0.25 mass % to 1.00 mass %, Si at 0.5 mass % or less, and Mn at 1.0 mass % or less, and the balance is composed of Fe and inevitable impurities; and a long blade for a steam turbine composed of the precipitate hardening stainless steel.Type: ApplicationFiled: June 13, 2012Publication date: December 20, 2012Inventors: Shinji OIKAWA, Hideo YODA, Masahiko ARAI, Hiroyuki DOI
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Publication number: 20120308772Abstract: An object is to provide a steam turbine member having excellent oxidation resistance at low cost without using an alloy coating such as a thermally sprayed or sintered body. The steam turbine member includes a substrate made of stainless steel containing Fe as a main component, 8 to 15 wt % of Cr, and 0.1 to 1.0 wt % of Mn. The steam turbine member has, on a surface of the substrate, an oxide film made of an oxide of a constituent element of the substrate. It is preferable that the oxide film thickness is 1 ?m or less. It is also preferable that the oxide film has a surface roughness Ra of 1.6 a or less.Type: ApplicationFiled: February 17, 2011Publication date: December 6, 2012Applicant: HITACHI, LTD.Inventors: Hiroshi Haruyama, Masahiko Arai, Hiroyuki Doi, Takeshi Izumi
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Patent number: 8225672Abstract: The present invention is intended to provide a method for assessing remaining lifespan of a bolt with higher precision than conventional methods, which can be applied to a bolt comprising a high alloy with fewer tissue changes caused by creep damage. The present invention provides a method for assessing the remaining lifespan of a bolt used at high temperatures, including: carrying out a creep test for a bolt material that constitutes a bolt to be assessed and determining a life-time and a life-elongation rate; determining a time-temperature parameter based on the life-time and the creep test temperature; creating a lifespan-assessment diagram by plotting the time-temperature parameter with respect to the life-elongation rate; measuring a elongation rate between before and after the use of the bolt to be assessed; and assessing the remaining lifespan of the bolt with the use of the elongation rate between before and after the use of the bolt to be assessed and the lifespan-assessment diagram.Type: GrantFiled: February 18, 2010Date of Patent: July 24, 2012Assignee: Hitachi, Ltd.Inventors: Masahiko Arai, Shinichi Kobayasji, Hiroyuki Doi, Hiroaki Chiba, Takashi Haneishi
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Publication number: 20120114496Abstract: It is an objective of the present invention to provide a precipitation-hardening martensitic stainless steel having well-balanced properties of high mechanical strength, high toughness and good corrosion resistance properties. There is provided a precipitation-hardening martensitic stainless steel comprising: 0.10 mass % or less of C; 13.0 to 15.0 mass % of Cr; 7.0 to 10.0 mass % of Ni; 2.0 to 3.0 mass % of Mo; 0.5 to 2.5 mass % of Ti; 0.5 to 2.5 mass % of Al; 0.5 mass % or less of Si; 0.1 to 1.0 mass % of Mn; and the balance including Fe and incidental impurities, in which the mass % content of the Ti (represented by [Ti content]), the mass % content of the Al (represented by [Al content]) and the mass % content of the C (represented by [C content]) satisfy relationships of “0.5?[Ti content]?2.5” and “0.5?[Al content]+2[C content]?2.7”.Type: ApplicationFiled: November 9, 2011Publication date: May 10, 2012Inventors: Shinji Oikawa, Hideo Yoda, Masahiko Arai, Hiroyuki Doi