Patents by Inventor Kiyoshi Uwai
Kiyoshi Uwai 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: 10774534Abstract: A high manganese content deformed reinforcing bar having an austenite single phase microstructure has excellent bending workability. A deformed reinforcing bar includes a chemical composition containing, in mass %, C: 0.7% or more and 1.2% or less, Si: 1.0% or less, Mn: 9% or more and 15% or less, Cr: 1.0% or less, P: 0.03% or less, and S: 0.05% or less, the balance consisting of Fe and inevitable impurities; and a microstructure comprising an austenite single phase. The ratio of the difference between the maximum and minimum hardness at a periphery of a cross-section perpendicular to the longitudinal direction with respect to a central average hardness is 15% or less. Two or more ribs extend in the longitudinal direction at equal intervals in a cross-sectional circumferential direction. The ratio of the difference between the maximum and minimum width of the ribs to the minimum width is 50% or less.Type: GrantFiled: February 8, 2017Date of Patent: September 15, 2020Assignee: JFE STEEL CORPORATIONInventors: Kiyoshi Uwai, Takashi Iwamoto, Kazukuni Hase
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Patent number: 10618101Abstract: A mechanical structural component is a toothed component obtained by performing cold forging and carburizing treatment on a steel having a predetermined chemical composition, in prior austenite grains after the carburizing treatment, an area ratio of crystal grains of 50 ?m or less is 80% or more, and an area ratio of crystal grains exceeding 300 ?m is 10% or less, and a total helix deviation of teeth after the carburizing treatment satisfies Formula (1) (Bmax/L)×103?5??(1) where Bmax is a maximum total helix deviation in all teeth in mm, and L is a face width in mm.Type: GrantFiled: July 10, 2014Date of Patent: April 14, 2020Assignee: JFE Steel CorporationInventors: Yuta Imanami, Takashi Iwamoto, Kiyoshi Uwai
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Patent number: 10253397Abstract: A pearlitic rail includes a composition including in % by mass: 0.70% to 0.90% of C; 0.1% to 1.5% of Si; 0.01% to 1.5% of Mn; 0.001% to 0.035% of P; 0.0005% to 0.030% of S; 0.1% to 2.0% of Cr, remainder of the composition consisting of Fe and inevitable impurities. Surface hardness of a rail top is not less than HB 430, and hardness at a depth of 25 mm from a surface of the rail top is not less than HB 410.Type: GrantFiled: March 25, 2014Date of Patent: April 9, 2019Assignee: JFE Steel CorporationInventors: Tatsumi Kimura, Kiyoshi Uwai, Shigeru Endo, Moriyasu Yamaguchi
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Publication number: 20190048590Abstract: A high manganese content deformed reinforcing bar having an austenite single phase microstructure has excellent bending workability. A deformed reinforcing bar includes a chemical composition containing, in mass %, C: 0.7% or more and 1.2% or less, Si: 1.0% or less, Mn: 9% or more and 15% or less, Cr: 1.0% or less, P: 0.03% or less, and S: 0.05% or less, the balance consisting of Fe and inevitable impurities; and a microstructure comprising an austenite single phase. The ratio of the difference between the maximum and minimum hardness at a periphery of a cross-section perpendicular to the longitudinal direction with respect to a central average hardness is 15% or less. Two or more ribs extend in the longitudinal direction at equal intervals in a cross-sectional circumferential direction. The ratio of the difference between the maximum and minimum width of the ribs to the minimum width is 50% or less.Type: ApplicationFiled: February 8, 2017Publication date: February 14, 2019Applicant: JFE STEEL CORPORATIONInventors: Kiyoshi UWAI, Takashi IWAMOTO, Kazukuni HASE
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Patent number: 10125416Abstract: The present invention provides a steel for nitrocarburizing having excellent mechanical workability before nitrocarburizing, and showing excellent fatigue properties after nitrocarburizing, which is suitable for applying in mechanical structural components for automobiles etc. prepared by adjusting the composition so that it contains in mass %, C: 0.01% or more and less than 0.10%, Si: 1.0% or less, Mn: 0.5% to 3.0%, P: 0.02% or less, S: 0.06% or less, Cr: 0.3% to 3.0%, Mo: 0.005% to 0.4%, V: 0.02% to 0.5%, Nb: 0.003% to 0.15%, Al: 0.005% to 0.2%, and Sb: 0.0005% to 0.02%, and the balance including Fe and incidental impurities, and setting the area ratio of bainite phase to the whole microstructure to more than 50%.Type: GrantFiled: July 22, 2013Date of Patent: November 13, 2018Assignees: JFE STEEL CORPORATION, JFE BARS AND SHAPESInventors: Yasuhiro Omori, Kiyoshi Uwai, Shinji Mitao, Takashi Iwamoto, Keisuke Ando, Kunikazu Tomita
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Patent number: 10041160Abstract: Provided is high strength steel for springs that, compared to conventional high strength steel for springs, has excellent decarburization resistance and scale exfoliation property, by optimization of the added amounts of C, Si, Mn, and Cr as well as of Sb and Sn. The steel for springs contains C: more than 0.45 mass % and less than 0.65 mass %, Si: 0.15 mass % or more and 0.70 mass % or less, Mn: 0.10 mass % or more and 1.00 mass % or less, Cr: 0.20 mass % or more and 1.50 mass % or less, P: 0.025 mass % or less, S: 0.025 mass % or less, O: 0.0015 mass % or less, Sb: 0.010 mass % or more and less than 0.030 mass %, and Sn: 0.010 mass % or more and 0.030 mass % or less, under predetermined conditions.Type: GrantFiled: September 11, 2014Date of Patent: August 7, 2018Assignees: JFE STEEL CORPORATION, SUMIHATSU CO., LTD., NHK SPRING CO., LTD.Inventors: Minoru Honjo, Kiyoshi Uwai, Shigeru Endo, Katsutoshi Yamashita, Koei Tsuru, Keiichi Fujie, Akira Tange
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Patent number: 9732395Abstract: A method is provided with which a bearing steel, even when obtained from an ingot, is made to have a segregation part reduced in the degree of segregation and maximum inclusion diameter. The ingot contains 0.56-0.70 mass % C, 0.15-0.50 mass %, excluding 0.50 mass %, Si, 0.60-1.50 mass % Mn, 0.50-1.10 mass % Cr, 0.05-0.5 mass % Mo, up to 0.025 mass % P, up to 0.025 mass % S, 0.005-0.500 mass % Al, up to 0.0015 mass % O, and 0.0030-0.015 mass % N, with the remainder comprising Fe and incidental impurities. The ingot has a degree of segregation of 2.8 or less and a predicted value of the maximum diameter of inclusions present in 30,000 mm2 of the ingot, as calculated by extreme value statistics, of 60 ?m or less.Type: GrantFiled: September 27, 2012Date of Patent: August 15, 2017Assignees: JFE STEEL CORPORATION, NTN CORPORATIONInventors: Minoru Honjo, Kiyoshi Uwai, Shinji Mitao
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Publication number: 20160222497Abstract: Provided is high strength steel for springs that, compared to conventional high strength steel for springs, has excellent decarburization resistance and scale exfoliation property, by optimization of the added amounts of C, Si, Mn, and Cr as well as of Sb and Sn. The steel for springs contains C: more than 0.45 mass % and less than 0.65 mass %, Si: 0.15 mass % or more and 0.70 mass % or less, Mn: 0.10 mass % or more and 1.00 mass % or less, Cr: 0.20 mass % or more and 1.50 mass % or less, P: 0.025 mass % or less, S: 0.025 mass % or less, O: 0.0015 mass % or less, Sb: 0.010 mass % or more and less than 0.030 mass %, and Sn: 0.010 mass % or more and 0.030 mass % or less, under predetermined conditions.Type: ApplicationFiled: September 11, 2014Publication date: August 4, 2016Applicants: JFE STEEL CORPORATION, SUMIHATSU CO., LTD., NHK SPRING CO., LTD.Inventors: Minoru HONJO, Kiyoshi UWAI, Shigeru ENDO, Katsutoshi YAMASHITA, Koei TSURU, Keiichi FUJIE, Akira TANGE
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Publication number: 20160207094Abstract: A mechanical structural component is a toothed component obtained by performing cold forging and carburizing treatment on a steel having a predetermined chemical composition, in prior austenite grains after the carburizing treatment, an area ratio of crystal grains of 50 ?m or less is 80% or more, and an area ratio of crystal grains exceeding 300 ?m is 10% or less, and a total helix deviation of teeth after the carburizing treatment satisfies Formula (1) (Bmax/L)×103?5??(1) where Bmax is a maximum total helix deviation in all teeth in mm, and L is a face width in mm.Type: ApplicationFiled: July 10, 2014Publication date: July 21, 2016Applicant: JFE Steel CorporationInventors: Yuta IMANAMI, Takashi IWAMOTO, Kiyoshi UWAI
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Publication number: 20160083820Abstract: A pearlitic rail includes a composition including in % by mass: 0.70% to 0.90% of C; 0.1% to 1.5% of Si; 0.01% to 1.5% of Mn; 0.001% to 0.035% of P; 0.0005% to 0.030% of S; 0.1% to 2.0% of Cr, remainder of the composition consisting of Fe and inevitable impurities. Surface hardness of a rail top is not less than HB 430, and hardness at a depth of 25 mm from a surface of the rail top is not less than HB 410.Type: ApplicationFiled: March 25, 2014Publication date: March 24, 2016Applicant: JFE STEEL CORPORATIONInventors: Tatsumi Kimura, Kiyoshi Uwai, Shigeru Endo, Moriyasu Yamaguchi
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Publication number: 20150159261Abstract: The present invention provides a steel for nitrocarburizing having excellent mechanical workability before nitrocarburizing, and showing excellent fatigue properties after nitrocarburizing, which is suitable for applying in mechanical structural components for automobiles etc. prepared by adjusting the composition so that it contains in mass %, C: 0.01% or more and less than 0.10%, Si: 1.0% or less, Mn: 0.5% to 3.0%, P: 0.02% or less, S: 0.06% or less, Cr: 0.3% to 3.0%, Mo: 0.005% to 0.4%, V: 0.02% to 0.5%, Nb: 0.003% to 0.15%, Al: 0.005% to 0.2%, and Sb: 0.0005% to 0.02%, and the balance including Fe and incidental impurities, and setting the area ratio of bainite phase to the whole microstructure to more than 50%.Type: ApplicationFiled: July 22, 2013Publication date: June 11, 2015Inventors: Yasuhiro Omori, Kiyoshi Uwai, Shinji Mitao, Takashi Iwamoto, Keisuke Ando, Kunikazu Tomita
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Patent number: 9034120Abstract: Provided is bearing steel excellent in workability after spheroidizing-annealing and in hydrogen fatigue resistance property after quenching and tempering. The bearing steel has a chemical composition containing, by mass %: 0.85% to 1.10% C; 0.30% to 0.80% Si; 0.90% to 2.00% Mn; 0.025% or less P; 0.02% or less S; 0.05% or less Al; 1.8% to 2.5% Cr; 0.15% to 0.4% Mo; 0.0080% or less N; and 0.0020% or less O, which further contains more than 0.0015% to 0.0050% or less Sb, with the balance being Fe and incidental impurities, to thereby effectively suppress the generation of WEA even in environment where hydrogen penetrates into the steel, so as to improve the roiling contact fatigue life and also the workability such as cuttability and forgeability of the material.Type: GrantFiled: November 29, 2011Date of Patent: May 19, 2015Assignee: JFE STEEL CORPORATIONInventors: Yasumasa Hirai, Kiyoshi Uwai
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Publication number: 20150041026Abstract: A method is provided with which a bearing steel, even when obtained from an ingot, is made to have a segregation part reduced in the degree of segregation and maximum inclusion diameter. The ingot contains 0.56-0.70 mass % C, 0.15-0.50 mass %, excluding 0.50 mass %, Si, 0.60-1.50 mass % Mn, 0.50-1.10 mass % Cr, 0.05-0.5 mass % Mo, up to 0.025 mass % P, up to 0.025 mass % S, 0.005-0.500 mass % Al, up to 0.0015 mass % O, and 0.0030-0.015 mass % N, with the remainder comprising Fe and incidental impurities. The ingot has a degree of segregation of 2.8 or less and a predicted value of the maximum diameter of inclusions present in 30,000 mm2 of the ingot, as calculated by extreme value statistics, of 60 ?m or less.Type: ApplicationFiled: September 27, 2012Publication date: February 12, 2015Applicants: JFE STEEL CORPORATION, NTN CORPORATIONInventors: Minoru Honjo, Kiyoshi Uwai, Shinji Mitao
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Publication number: 20150020926Abstract: According to the present invention, it is possible to obtain steel for nitrocarburizing having a predetermined chemical composition, a bainite area ratio exceeding 50% and excellent machinability by cutting before nitrocarburizing, and having strength and toughness equivalent to conventional steel, such as SCr420 carburized steel material, and excellent fatigue properties after nitrocarburizing.Type: ApplicationFiled: February 15, 2013Publication date: January 22, 2015Inventors: Takashi Iwamoto, Keisuke Ando, Kunikazu Tomita, Yasuhiro Omori, Kiyoshi Uwai, Shinji Mitao
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Publication number: 20150004051Abstract: A high strength spring steel suppresses ferrite decarburization in a surface layer of a predetermined wire rod manufactured by hot rolling therefrom and possesses excellent decarburization resistance, as compared to conventional high strength spring steel, by optimizing the amount of C, Si, Mn, Cr, Mo and Sb to be added. The spring steel contains, under a certain relationship: 0.35 mass %?C?0.45 mass %; 1.75 mass %?Si?2.40 mass %; 0.1 mass %?Mn?1.0 mass %; 0.01 mass %?Cr<0.50 mass %; 0.01 mass %?Mo?1.00 mass %; P?0.025 mass %; S?0.025 mass %; and O?0.0015 mass %; and at least one selected from 0.035 mass %?Sb?0.12 mass % and 0.035 mass %?Sn?0.20 mass %.Type: ApplicationFiled: February 14, 2013Publication date: January 1, 2015Inventors: Minoru Honjo, Kiyoshi Uwai, Shinji Mitao
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Patent number: 8894779Abstract: Provided is bearing steel excellent in post spheroidizing-annealing workability and in post quenching-tempering hydrogen fatigue resistance property. The bearing steel has a chemical composition containing, by mass %: 0.85% to 1.10% C; 0.30% to 0.80% Si; 0.90% to 2.00% Mn; 0.025% or less P; 0.02% or less S; 0.05% or less Al; 1.8% to 2.5% Cr; 0.15% to 0.4% Mo; 0.0080% or less N; 0.0020% or less O; and the balance being Fe and incidental impurities, to thereby effectively suppress the generation of WEA even in environment where hydrogen penetrates into the steel, so as to improve the rolling contact fatigue life and also the workability such as cuttability and forgeability of the material.Type: GrantFiled: November 24, 2011Date of Patent: November 25, 2014Assignee: JFE Steel CorporationInventors: Yasumasa Hirai, Kiyoshi Uwai
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Publication number: 20130224065Abstract: Provided is bearing steel excellent in workability after spheroidizing-annealing and in hydrogen fatigue resistance property after quenching and tempering. The bearing steel has a chemical composition containing, by mass %: 0.85% to 1.10% C; 0.30% to 0.80% Si; 0.90% to 2.00% Mn; 0.025% or less P; 0.02% or less S; 0.05% or less Al; 1.8% to 2.5% Cr; 0.15% to 0.4% Mo; 0.0080% or less N; and 0.0020% or less O, which further contains more than 0.0015% to 0.0050% or less Sb, with the balance being Fe and incidental impurities, to thereby effectively suppress the generation of WEA even in environment where hydrogen penetrates into the steel, so as to improve the roiling contact fatigue life and also the workability such as cuttability and forgeability of the material.Type: ApplicationFiled: November 29, 2011Publication date: August 29, 2013Applicant: JFE STEEL CORPORATIONInventors: Yasumasa Hirai, Kiyoshi Uwai
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Publication number: 20130189147Abstract: Provided is bearing steel excellent in post spheroidizing-annealing workability and in post quenching-tempering hydrogen fatigue resistance property. The bearing steel has a chemical composition containing, by mass %: 0.85% to 1.10% C; 0.30% to 0.80% Si; 0.90% to 2.00% Mn; 0.025% or less P; 0.02% or less S; 0.05% or less Al; 1.8% to 2.5% Cr; 0.15% to 0.4% Mo; 0.0080% or less N; 0.0020% or less O; and the balance being Fe and incidental impurities, to thereby effectively suppress the generation of WEA even in environment where hydrogen penetrates into the steel, so as to improve the rolling contact fatigue life and also the workability such as cuttability and forgeability of the material.Type: ApplicationFiled: November 24, 2011Publication date: July 25, 2013Applicant: JFE STEEL CORPORATIONInventors: Yasumasa Hirai, Kiyoshi Uwai
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Patent number: 8302309Abstract: A method is directed to a production of a bearing device for a wheel including an inner member and an outer member rotatable relative to each other through a plurality of rolling elements, in which a component part forming one of the inner member and the outer member is a hot forged product. In the practice of this method, during or at the end of a hot forging step for hot forging the component part, a portion of the component part is cooled by spraying a coolant or by controlling an atmospheric temperature, to thereby render a matrix of the component part to represent a standard structure and render a surface portion of the component part to represent a non-standard structure.Type: GrantFiled: July 10, 2006Date of Patent: November 6, 2012Assignees: NTN Corporation, JFE Steel CorporationInventors: Isao Hirai, Kohei Yoshino, Takayasu Takubo, Kazuhiko Yoshida, Kazukuni Hase, Hideto Kimura, Kiyoshi Uwai, Takaaki Toyooka
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Publication number: 20090106980Abstract: A method is directed to a production of a bearing device for a wheel including an inner member (1) and an outer member (2) rotatable relative to each other through a plurality of rolling elements (3), in which a component part forming one of the inner member (1) and the outer member (2) is a hot forged product. In the practice of this method, during or at the end of a hot forging step for hot forging the component part, a portion of the component part is cooled by spraying a coolant or by controlling an atmospheric temperature, to thereby render a matrix of the component part to represent a standard structure and render a surface portion of the component part to represent a non-standard structure (30).Type: ApplicationFiled: July 10, 2006Publication date: April 30, 2009Inventors: Isao Hirai, Kohei Yoshino, Takayasu Takubo, Kazuhiko Yoshida, Kazukuni Hase, Hideto Kimura, Kiyoshi Uwai, Takaaki Toyooka