Patents by Inventor Tomohiko Omura
Tomohiko Omura 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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Publication number: 20220136469Abstract: A steel pipe for a fuel injection pipe has a chemical composition consisting of, by mass %: C: 0.17 to 0.27%, Si: 0.05 to 0.40%, Mn: 0.30 to 2.00%, P: 0.020% or less, S: 0.0100% or less, O: 0.0040% or less, Ca: 0.0010% or less, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, Ti: 0.005 to 0.015%, Nb: 0.015 to 0.045%, Cr: 0 to 1.00%, Mo: 0 to 1.00%, Cu: 0 to 0.50%, Ni: 0 to 0.50%, V: 0 to 0.15%, and the balance: Fe and impurities. The metal micro-structure consists substantially of tempered martensite, or tempered martensite and tempered bainite. The hardness is within the range of 350 to 460 HV1. A lattice spacing of a (211) diffraction plane measured by CoK? characteristic X-ray diffraction is 1.1716 ? or less, and a half-value width of the (211) diffraction plane is 1.200° or less. The number density of cementite having a diameter of 50 nm or more is 20/?m2 or less.Type: ApplicationFiled: February 13, 2020Publication date: May 5, 2022Inventors: Taizo MAKINO, Masahiro YAMAZAKI, Tomohiko OMURA, Yuji ARAI, Osamu ENDO, Naoki SERIZAWA, Tatsuya MASUDA
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Patent number: 10662497Abstract: A high-strength austenitic stainless steel, which has good hydrogen embrittlement resistance and hydrogen fatigue resistance, has a chemical composition including, in mass %, C: up to 0.10%; Si: up to 1.0%; Mn: not less than 3.0% and less than 7.0 %; Cr: 15 to 30%; Ni: not less than 12.0% and less than 17.0%; Al: up to 0.10%; N: 0.10 to 0.50%; P: up to 0.050%; S: up to 0.050%; at least one of V: 0.01 to 1.0% and Nb: 0.01 to 0.50%; and other elements, the balance being Fe and impurities, wherein the ratio of the minor axis to the major axis of the austenite crystal grains is greater than 0.1, the crystal grain size number of austenite crystal grains is not lower than 8.0, and the tensile strength is not less than 1000 MPa.Type: GrantFiled: October 22, 2015Date of Patent: May 26, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Jun Nakamura, Tomohiko Omura, Hiroyuki Hirata, Kana Jotoku, Takahiro Osuki
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Patent number: 10556298Abstract: A welded joint having high strength and good hydrogen embrittlement resistance is provided. A welded joint is a welded joint obtained by welding a base material using a welding material. The base material has a chemical composition of, in mass %: C: 0.005 to 0.1%; Si: up to 1.2%; Mn: 2.5 to 6.5%; Ni: 8 to 15%; Cr: 19 to 25%; Mo: 0.01 to 4.5%; V: 0.01 to 0.5%; Nb: 0.01 to 0.5% Al: less than 0.05%; N: 0.15 to 0.45%; O: up to 0.02%; P: up to 0.05%; and S: up to 0.04%, and a balance being iron and impurities, and which satisfies Equation (1). The welding material has a chemical composition which satisfies Equations (1) and (2). Ni+0.65Cr+0.98Mo+1.05Mn+0.35Si+12.6C?29??(1) 0.31C+0.048Si?0.02Mn?0.056Cr+0.007Ni?0.013Mo??1.Type: GrantFiled: February 20, 2015Date of Patent: February 11, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Kana Jotoku, Hiroyuki Hirata, Tomohiko Omura, Jun Nakamura, Takahiro Osuki
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Patent number: 10407758Abstract: A steel for oil country tubular goods includes, as a chemical composition, by mass %, C, Si, Mn, Al, Mo, P, S, O, N, and a balance containing Fe and impurities, wherein a full width at half maximum HW of a crystal plane corresponding to a (211) crystal plane of an ? phase and a carbon content expressed in mass % in the chemical composition satisfy HW×C1/2?0.38, the carbon content and a molybdenum content expressed in mass % in the chemical composition satisfy C×Mo?0.6, a number of M2C carbides having a hexagonal crystal structure and having an equivalent circle diameter of 1 nm or more is 5 pieces or more per one square micron, and an yield strength is 758 MPa or more.Type: GrantFiled: June 17, 2013Date of Patent: September 10, 2019Assignee: NIPPON STEEL CORPORATIONInventors: Tomohiko Omura, Yuji Arai, Kaori Kawano, Akihiro Sakamoto, Kazuo Okamura, Kenji Yamamoto, Keiichi Kondo, Koji Nagahashi, Masanao Seo
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Patent number: 10316383Abstract: There is provided an austenitic stainless steel having a high strength and an excellent hydrogen brittleness resistance and further having an excellent machinability. The austenitic stainless steel of the present embodiment has a chemical composition including: in mass %, C: 0.10% or less; Si: 1.0% or less; Mn: 2.1 to 6.0%; P: 0.045% or less; S: 0.1% or less; Ni: 8.0 to 16.0%; Cr: 15.0 to 30.0%; Mo: 1.0 to 5.0%; N: 0.05 to 0.45%; Nb: 0 to 0.50%; and V: 0 to 0.50%, with the balance being Fe and impurities, and satisfying Formula (1). The austenitic stainless steel of the present embodiment has a grain size number of less than 8.0 and a tensile strength of 690 MPa or more. 15?12.6C+1.Type: GrantFiled: April 17, 2015Date of Patent: June 11, 2019Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Etsuo Dan, Masaaki Terunuma, Takahiro Osuki, Tomohiko Omura, Jun Nakamura
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Patent number: 10266909Abstract: There is provided an austenitic stainless steel for high-pressure hydrogen gas consisting, by mass percent, of C: 0.10% or less, Si: 1.0% or less, Mn: 3% or more to less than 7%, Cr: 15 to 30%, Ni: 10% or more to less than 17%, Al: 0.10% or less, N: 0.10 to 0.50%, and at least one kind of V: 0.01 to 1.0% and Nb: 0.01 to 0.50%, the balance being Fe and impurities, wherein in the impurities, the P content is 0.050% or less and the S content is 0.050% or less, the tensile strength is 800 MPa or higher, the grain size number (ASTM E112) is No. 8 or higher, and alloy carbo-nitrides having a maximum diameter of 50 to 1000 nm are contained in the number of 0.4/?m2 or larger in cross section observation.Type: GrantFiled: March 19, 2012Date of Patent: April 23, 2019Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Tomohiko Omura, Jun Nakamura, Hirokazu Okada, Hiroyuki Semba, Yusaku Tomio, Hiroyuki Hirata, Masaaki Igarashi, Kazuhiro Ogawa, Masaaki Terunuma
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Patent number: 10260125Abstract: There is provided an austenitic stainless steel for high-pressure hydrogen gas consisting, by mass percent, of C: 0.10% or less, Si: 1.0% or less, Mn: 3% or more to less than 7%, Cr: 15 to 30%, Ni: 10% or more to less than 17%, Al: 0.10% or less, N: 0.10 to 0.50%, and at least one kind of V: 0.01 to 1.0% and Nb: 0.01 to 0.50%, the balance being Fe and impurities, wherein in the impurities, the P content is 0.050% or less and the S content is 0.050% or less, the tensile strength is 800 MPa or higher, the grain size number (ASTM E112) is No. 8 or higher, and alloy carbo-nitrides having a maximum diameter of 50 to 1000 nm are contained in the number of 0.4/?m2 or larger in cross section observation.Type: GrantFiled: June 28, 2016Date of Patent: April 16, 2019Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Tomohiko Omura, Jun Nakamura, Hirokazu Okada, Hiroyuki Semba, Yusaku Tomio, Hiroyuki Hirata, Masaaki Igarashi, Kazuhiro Ogawa, Masaaki Terunuma
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Patent number: 10246765Abstract: A martensitic Cr-containing steel having excellent corrosion resistance, SSC resistance, and IGHIC resistance is provided. A martensitic Cr-containing steel according to the present invention includes: a chemical composition consisting of, by mass %, Si: 0.05 to 1.0%, Mn: 0.1 to 1.0%, Cr: 8 to 12%, V: 0.01 to 1.0%, sol. Al: 0.005 to 0.10%, with the balance being Fe and impurities, wherein an effective Cr amount defined by “Cr?16.6×C” is not less than 8%, and an Mo equivalent defined by “Mo+0.5×W” is 0.03 to 2%; a micro-structure wherein a grain size number of prior-austenite crystal grain is not less than 8.0; and a yield strength of less than 379 to 551 MPa, wherein a grain-boundary segregation ratio of Mo and W is not less than 1.5.Type: GrantFiled: December 24, 2014Date of Patent: April 2, 2019Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Tomohiko Omura, Yusaku Tomio, Hideki Takabe, Toshio Mochizuki
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Publication number: 20180258505Abstract: An austenitic stainless steel with improved strength, ductility and weldability is provided. An austenitic stainless steel has a chemical composition of, in mass %: 0.005 to 0.07% C; 0.1 to 1.2% Si; 3.2 to 6.5% Mn; 9 to 14% Ni; a total of not less than 0.005% and less than 3% of at least one of Cu and Co; 19 to 24% Cr; 1 to 4% Mo; 0.05 to 0.4% Nb; 0.15 to 0.50% N; up to 0.05% Al; up to 0.03% P; up to 0.002% S; up to 0.02% O; 0 to 0.5% V; 0 to 0.5% Ti; 0 to 0.01% B; 0 to 0.05% Ca; 0 to 0.05% Mg; 0 to 0.5% REM; and the balance being Fe and impurities, where the amount of Nb analyzed as residues after electrolytic extraction is 0.01 to 0.3 mass %.Type: ApplicationFiled: July 6, 2016Publication date: September 13, 2018Inventors: Hiroyuki Hirata, Kana Jotoku, Tomohiko Omura, Jun Nakamura, Masaaki Terunuma, Takahiro Osuki, Masaki Ueyama
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Patent number: 10036078Abstract: Low-alloy oil-well steel pipe includes a composition consisting, in mass %, of C: 0.40 to 0.65%, Si: 0.05 to 0.50%, Mn: 0.10 to 1.00%, P: 0.020% or less, S: 0.0020% or less, Cu: 0.15% or less, Cr: 0.40 to 1.50%, Mo: 0.50 to 2.50%, V: 0.05 to 0.25%, Ti: 0 to less than 0.01%, Nb: 0.01 to 0.2%, sol. Al: 0.010 to 0.100%, N: 0.006% or less, B: 0 to 0.0015%, and Ca: 0 to 0.003%, the balance being Fe and impurities. The structure has tempered martensite and 0 to less than 2% volume ratio of retained austenite. A grain size number of prior-austenite grain in the structure is 9.0 or more. An equivalent circular diameter of a sub-structure surrounded by a boundary having a crystal orientation difference of 15° or more from a packet boundary, a block boundary and a lath boundary is 3 ?m or less for the tempered martensite.Type: GrantFiled: July 23, 2014Date of Patent: July 31, 2018Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Yuji Arai, Tomohiko Omura, Keiichi Kondo
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Publication number: 20180135154Abstract: The low alloy steel for oil country tubular goods according to the present invention has a chemical composition containing, by mass percent, C: 0.56 to 1.00%, Si: 0.05 to 0.50%, Mn: 0.05 to 1.00%, P: at most 0.025%, 5: at most 0.010%, Al: 0.005 to 0.100%, Mo: 0.40 to 1.00%, V: 0.05 to 0.30%, and O: at most 0.010%, the balance being Fe and impurities, wherein the yield stress thereof is at least 862 MPa, and the half-value width of a [211] crystal surface obtained by X-ray diffraction is at most 0.50°.Type: ApplicationFiled: January 10, 2018Publication date: May 17, 2018Inventors: Tomohiko OMURA, Yuji ARAI, Kaori KAWANO, Akihiro SAKAMOTO, Kazuo OKAMURA, Kenji YAMAMOTO, Keiichi KONDO
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Patent number: 9909198Abstract: The low alloy steel for oil country tubular goods according to the present invention has a chemical composition containing, by mass percent, C: 0.56 to 1.00%, Si: 0.05 to 0.50%, Mn: 0.05 to 1.00%, P: at most 0.025%, S: at most 0.010%, Al: 0.005 to 0.100%, Mo: 0.40 to 1.00%, V: 0.05 to 0.30%, and O: at most 0.010%, the balance being Fe and impurities, wherein the yield stress thereof is at least 862 MPa, and the half-value width of a [211] crystal surface obtained by X-ray diffraction is at most 0.50°.Type: GrantFiled: November 5, 2012Date of Patent: March 6, 2018Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Tomohiko Omura, Yuji Arai, Kaori Kawano, Akihiro Sakamoto, Kazuo Okamura, Kenji Yamamoto, Keiichi Kondo
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Publication number: 20170314092Abstract: A high-strength austenitic stainless steel, which has good hydrogen embrittlement resistance and hydrogen fatigue resistance, has a chemical composition including, in mass %, C: up to 0.10%; Si: up to 1.0%; Mn: not less than 3.0% and less than 7.0 %; Cr: 15 to 30%; Ni: not less than 12.0% and less than 17.0%; Al: up to 0.10%; N: 0.10 to 0.50%; P: up to 0.050%; S: up to 0.050%; at least one of V: 0.01 to 1.0% and Nb: 0.01 to 0.50%; and other elements, the balance being Fe and impurities, wherein the ratio of the minor axis to the major axis of the austenite crystal grains is greater than 0.1, the crystal grain size number of austenite crystal grains is not lower than 8.0, and the tensile strength is not less than 1000 MPa.Type: ApplicationFiled: October 22, 2015Publication date: November 2, 2017Applicant: Nippon Steel & Sumitomo Metal CorporationInventors: Jun NAKAMURA, Tomohiko OMURA, Hiroyuki HIRATA, Kana JOTOKU, Takahiro OSUKI
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Patent number: 9783876Abstract: A stainless steel for oil wells which has excellent high-temperature corrosion resistance and can stably obtain a strength of not less than 758 MPa is provided. The stainless steel for oil wells contains, by masse, C: not more than 0.05%, Si: not more than 1.0%, Mn: 0.01 to 1.0%, P: not more than 0.05%, S: less than 0.002%, Cr: 16 to 18%, Mo: 1.8 to 3%, Cu: 1.0 to 3.5%, Ni: 3.0 to 5.5%, Co: 0.01 to 1.0%, Al: 0.001 to 0.1%, O: not more than 0.05%, and N: not more than 0.05%, the balance being Fe and impurities, and satisfies Formulas (1) and (2): Cr+4Ni+3Mo+2Cu?44??(1) Cr+3Ni+4Mo+2Cu/3?46??(2) where each symbol of element in Formulas (1) and (2) is substituted by the content (mass %) of a corresponding element.Type: GrantFiled: February 27, 2013Date of Patent: October 10, 2017Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Shinjiro Nakatsuka, Taro Ohe, Hisashi Amaya, Hideki Takabe, Yohei Otome, Yusaku Tomio, Masanao Seo, Tomohiko Omura, Kunio Kondo
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Patent number: 9777352Abstract: To provide an oil-well steel pipe having excellent SSC resistance. The oil-well steel pipe according to the present invention contains, by mass percent, C: 0.15 to 0.35%, Si: 0.1 to 0.75%, Mn: 0.1 to 1.0%, Cr: 0.1 to 1.7%, Mo: 0.1 to 1.2%, Ti: 0.01 to 0.05%, Nb: 0.010 to 0.030%, Al: 0.01 to 0.1%, P: at most 0.03%, S: at most 0.01%, N: at most 0.007%, and O: at most 0.01%, the balance being Fe and impurities. The Ti content and the Nb content in a residue obtained by bromine-methanol extraction satisfy equation (1): 100×[Nb]/([Ti]+[Nb])?27.5??(1) where the Ti content (mass %) and the Nb content (mass %) in the residue are substituted for [Ti] and [Nb].Type: GrantFiled: August 17, 2012Date of Patent: October 3, 2017Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Atsushi Soma, Tomohiko Omura, Yuji Arai, Mitsuhiro Numata, Toru Takayama, Masanao Seo
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Publication number: 20170029911Abstract: There is provided an austenitic stainless steel having a high strength and an excellent hydrogen brittleness resistance and further having an excellent machinability. The austenitic stainless steel of the present embodiment has a chemical composition including: in mass %, C: 0.10% or less; Si: 1.0% or less; Mn: 2.1 to 6.0%; P: 0.045% or less; S: 0.1% or less; Ni: 8.0 to 16.0%; Cr: 15.0 to 30.0%; Mo: 1.0 to 5.0%; N: 0.05 to 0.45%; Nb: 0 to 0.50%; and V: 0 to 0.50%, with the balance being Fe and impurities, and satisfying Formula (1). The austenitic stainless steel of the present embodiment has a grain size number of less than 8.0 and a tensile strength of 690 MPa or more. 15?12.6C+1.Type: ApplicationFiled: April 17, 2015Publication date: February 2, 2017Inventors: Etsuo DAN, Masaaki TERUNUMA, Takahiro OSUKI, Tomohiko OMURA, Jun NAKAMURA
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Patent number: 9546408Abstract: A method for quenching a steel pipe by water cooling from an outer surface thereof, where pipe end portions are not subjected to water cooling, and at least part of a main body other than the pipe end portions is subjected to water cooling. A region(s) that is not subjected to direct water cooling over an entire circumference thereof can be along an axial direction at least in part of the main body other than the pipe end portions. The start and stop of water cooling can be intermittent at least in part of the quenching. During the water cooling of the pipe outer surface, an intensified water cooling can be performed in a temperature range in which the pipe outer surface temperature is higher than Ms point. Thereafter, the cooling can be switched to moderate cooling so that the outer surface is cooled down to Ms point or lower.Type: GrantFiled: March 13, 2012Date of Patent: January 17, 2017Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Akihiro Sakamoto, Kazuo Okamura, Kenji Yamamoto, Tomohiko Omura, Yuji Arai
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Publication number: 20160354870Abstract: A welded joint having high strength and good hydrogen embrittlement resistance is provided. A welded joint is a welded joint obtained by welding a base material using a welding material. The base material has a chemical composition of, in mass %: C: 0.005 to 0.1%; Si: up to 1.2%; Mn: 2.5 to 6.5%; Ni: 8 to 15%; Cr: 19 to 25%; Mo: 0.01 to 4.5%; V: 0.01 to 0.5%; Nb: 0.01 to 0.5% Al: less than 0.05%; N: 0.15 to 0.45%; O: up to 0.02%; P: up to 0.05%; and S: up to 0.04%, and a balance being iron and impurities, and which satisfies Equation (1). The welding material has a chemical composition which satisfies Equations (1) and (2). Ni+0.65Cr+0.98Mo+1.05Mn+0.35Si+12.6C?29??(1) 0.31C+0.048Si—0.02Mn?0.056Cr+0.007Ni?0.013Mo??1.Type: ApplicationFiled: February 20, 2015Publication date: December 8, 2016Inventors: Kana JOTOKU, Hiroyuki HIRATA, Tomohiko OMURA, Jun NAKAMURA, Takihiro OSUKI
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Publication number: 20160326617Abstract: A martensitic Cr-containing steel having excellent corrosion resistance, SSC resistance, and IGHIC resistance is provided. A martensitic Cr-containing steel according to the present invention includes: a chemical composition consisting of, by mass %, Si: 0.05 to 1.0%, Mn: 0.1 to 1.0%, Cr: 8 to 12%, V: 0.01 to 1.0%, sol. Al: 0.005 to 0.10%, with the balance being Fe and impurities, wherein an effective Cr amount defined by “Cr?16.6×C” is not less than 8%, and an Mo equivalent defined by “Mo+0.5×W” is 0.03 to 2%; a micro-structure wherein a grain size number of prior-austenite crystal grain is not less than 8.0; and a yield strength of less than 379 to 551 MPa, wherein a grain-boundary segregation ratio of Mo and W is not less than 1.5.Type: ApplicationFiled: December 24, 2014Publication date: November 10, 2016Inventors: Tomohiko Omura, Yusaku Tomio, Hideki Takabe, Toshio Mochizuki
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Publication number: 20160304983Abstract: There is provided an austenitic stainless steel for high-pressure hydrogen gas consisting, by mass percent, of C: 0.10% or less, Si: 1.0% or less, Mn: 3% or more to less than 7%, Cr: 15 to 30%, Ni: 10% or more to less than 17%, Al: 0.10% or less, N: 0.10 to 0.50%, and at least one kind of V: 0.01 to 1.0% and Nb; 0.01 to 0.50%, the balance being Fe and impurities, wherein in the impurities, the P content is 0.050% or less and the S content is 0.050% or less, the tensile strength is 800 MPa or higher, the grain size number (ASTM E112) is No. 8 or higher, and alloy carbo-nitrides having a maximum diameter of 50 to 1000 nm are contained in the number of 0.4/?m2 or larger in cross section observation.Type: ApplicationFiled: June 28, 2016Publication date: October 20, 2016Inventors: Tomohiko OMURA, Jun Nakamura, Hirokazu Okada, Hiroyuki Semba, Yusaku Tomio, Hiroyuki Hirata, Masaaki Igarashi, Kazuhiro Ogawa, Masaaki Terunuma