Patents by Inventor Takumi Ujiro
Takumi Ujiro 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: 9587297Abstract: A ferritic stainless steel excellent in corrosion resistance and conductivity and a method for manufacturing the same, the stainless steel having a chemical composition containing, by mass %, C: 0.001% or more and 0.05% or less, Si: 0.001% or more and 0.5% or less, Mn: 0.001% or more and 1.0% or less, Al: 0.001% or more and 0.5% or less, N: 0.001% or more and 0.05% or less, Cr; 17% or more and 23% or less, Mo: 0.1% or less and the balance being Fe and inevitable impurities and a passivation film on the surface of the stainless steel which is obtained by immersing the stainless steel in a solution for an immersion treatment, said solution mainly contains hydrofluoric acid or a liquid mixture of hydrofluoric acid and nitric acid.Type: GrantFiled: October 6, 2011Date of Patent: March 7, 2017Assignee: JFE STEEL CORPORATIONInventors: Tomohiro Ishii, Shin Ishikawa, Takumi Ujiro
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Patent number: 9279172Abstract: Ferritic stainless steel is excellent in terms of both oxidation resistance and thermal fatigue resistance without adding expensive elements, such as Mo or W. The ferritic stainless steel, contains: C: 0.015 mass % or lower, Si: 1.0 mass % or lower, Mn: 1.0 mass % or lower, P: 0.04 mass % or lower, S: 0.010 mass % or lower, Cr: 16 to 23 mass % or lower, N: 0.015 mass % or lower, Nb: 0.3 to 0.65 mass %, Ti: 0.15 mass % or lower, Mo: 0.1 mass % or lower, W: 0.1 mass % or lower, Cu: 1.0 to 2.5 mass %, Al: 0.2 to 1.5 mass %, and the balance of Fe and inevitable impurities.Type: GrantFiled: March 5, 2009Date of Patent: March 8, 2016Assignee: JFE Steel CorporationInventors: Yasushi Kato, Norimasa Hirata, Tetsuyuki Nakamura, Takumi Ujiro, Hiroki Ota
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Patent number: 9273382Abstract: A stainless steel foil contains, in percent by mass, 0.05% or less of C, 2.0% or less of Si, 1.0% or less of Mn, 0.003% or less of S, 0.05% or less of P, 25.0% to 35.0% of Cr, 0.05% to 0.30% of Ni, 3.0% to 10.0% of Al, 0.10% or less of N, 0.02% or less of Ti, 0.02% or less of Nb, 0.02% or less of Ta, 0.005% to 0.20% of Zr, 0.02% or less of Ce, 0.03% to 0.20% of REM excluding Ce, 0.5% to 6.0% in total of at least one of Mo and W, and the balance being Fe and incidental impurities.Type: GrantFiled: March 18, 2011Date of Patent: March 1, 2016Assignee: JFE Steel CorporationInventors: Akito Mizutani, Kunio Fukuda, Shin Ishikawa, Atsutaka Honda, Yasuhiro Yamaguchi, Yasushi Kato, Hiroki Ota, Mitsuyuki Fujisawa, Takumi Ujiro, Hideaki Yamashita
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Patent number: 9157137Abstract: An object is to provide a ferritic stainless steel having excellent oxidation resistance, while preventing a deterioration in formability, without adding expensive chemical elements such as Mo and W. Specifically, the ferritic stainless steel excellent in oxidation resistance having a chemical composition containing, by mass %, C: 0.015% or less, Si: 0.40% or more and 1.00% or less, Mn: 1.00% or less, P: 0.040% or less, S: 0.010% or less, Cr: 12.0% or more and 23.0% or less, N: 0.015% or less, Nb: 0.30% or more and 0.65% or less, Ti: 0.150% or less, Mo: 0.10% or less, W: 0.10% or less, Cu: less than 1.00%, Al: 0.20% or more and 1.00% or less, while the relationship Si?Al is satisfied, and the balance being Fe and inevitable impurities.Type: GrantFiled: October 12, 2011Date of Patent: October 13, 2015Assignee: JFE STEEL CORPORATIONInventors: Tetsuyuki Nakamura, Hiroki Ota, Takumi Ujiro
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Patent number: 9130199Abstract: A stainless steel for a fuel cell having good corrosion resistance throughout a wide potential range and a method for producing the same are provided. In particular, a coating having an intensity ratio [(OO/OH)/(Cr/Fe)] of 1.0 or more determined by X-ray photoelectron spectroscopy analysis is formed by performing an anodic electrolyzation treatment on a surface of a stainless steel in an electrolyte solution, the stainless steel containing 16% by mass or more of Cr and preferably having a composition that includes, in terms of percent by mass, C: 0.03% or less, Si: 1.0% or less, Mn: 1.0% or less, S: 0.01% or less, P: 0.05% or less, Al: 0.20% or less, N: 0.03% or less, Cr: 20 to 40%, at least one selected from Nb, Ti, and Zr, in total: 1.0% or less, and the balance being Fe and unavoidable impurities.Type: GrantFiled: July 22, 2010Date of Patent: September 8, 2015Assignee: JFE Steel CorporationInventors: Shinsuke Ide, Tomohiro Ishii, Naoki Nishiyama, Shin Ishikawa, Takumi Ujiro, Noriko Makiishi
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Patent number: 8852361Abstract: A stainless steel sheet with excellent heat and corrosion resistances for a brake disk is provided. Specifically, in mass %, C: less than 0.10%, Si: 1.0% or less, Mn: 1.0 to 2.5%, P: 0.04% or less, S: 0.01% or less, Cr: more than 11.5% but not more than 15.0%, Ni: 0.1 to 1.0%, Al: 0.10% or less, Nb: more than 0.08% but not more than 0.6%, V: 0.02 to 0.3%, and N: more than 0.03% but not more than 0.10% are contained so that 0.03?{C+N?(13/93)Nb}?0.10, (5Cr+10Si+15Mo+30Nb+50V?9Ni?5Mn?3Cu?225N?270C)?45, and {(14/50)V+(14/90)Nb}<N (wherein Cr, Si, Mo, Nb, Ni, Mn, Cu, V, N, and C represent the contents (mass %) of the corresponding elements) are satisfied. With such a composition, the stainless steel sheet for a brake disk can be provided with both excellent heat resistance and excellent corrosion resistance after tempering.Type: GrantFiled: October 20, 2005Date of Patent: October 7, 2014Assignee: JFE Steel CorporationInventors: Junichiro Hirasawa, Takumi Ujiro, Osamu Furukimi
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Patent number: 8657971Abstract: A brake disk excellent in temper softening resistance and toughness comprising, by mass, 0.1% or less of C, 1.0% or less of Si, 2.0% or less of Mn, 10.5% to 15.0% of Cr, and 0.1% or less of N, the remainder being Fe and unavoidable impurities, such that the following inequalities are satisfied: 5Cr+10Si+15Mo+30Nb?9Ni?5Mn?3Cu?225N?270C<45 (1) and 0.03?{C+N?(13/92)Nb}?0.09 (2) wherein Cr, Si, Mo, Nb, Ni, Mn, Cu, N, and C each represent the content of the corresponding elements on a mass percent basis, and having a martensitic structure having prior-austenite grains with an average diameter of 8 to less than 15 ?m.Type: GrantFiled: October 5, 2006Date of Patent: February 25, 2014Assignee: JFE Steel CorporationInventors: Junichiro Hirasawa, Takumi Ujiro, Osamu Furukimi
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Patent number: 8607941Abstract: A steel sheet for a brake disc contains, on a mass percent basis, 0.02% or more and less than 0.10% C, 0.6% or less Si, more than 0.5% and 2.0% or less Mn, 0.06% or less P, 0.01% or less S, 0.05% or less Al, 11.0% to 13.5% Cr, 0.01% to 0.30% Ni, 0.10% to 0.60% Nb, 0.03% or more and less than 0.10% N, more than 0.0010% and 0.0060% or less B, and the balance being Fe and incidental impurities, and the steel sheet after quenching has a hardness of 32 HRC to 40 HRC on a Rockwell hardness scale C (HRC).Type: GrantFiled: May 31, 2010Date of Patent: December 17, 2013Assignee: JFE Steel CorporationInventors: Katsuhisa Yamauchi, Mitsuyuki Fujisawa, Yasushi Kato, Hiroki Ota, Hideya Furusawa, Takumi Ujiro
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Publication number: 20130316262Abstract: A ferritic stainless steel excellent in corrosion resistance and conductivity and a method for manufacturing the same, the stainless steel having a chemical composition containing, by mass %, C: 0.001% or more and 0.05% or less, Si: 0.001% or more and 0.5% or less, Mn: 0.001% or more and 1.0% or less, Al: 0.001% or more and 0.5% or less, N: 0.001% or more and 0.05% or less, Cr; 17% or more and 23% or less, Mo: 0.1% or less and the balance being Fe and inevitable impurities and a passivation film on the surface of the stainless steel which is obtained by immersing the stainless steel in a solution for an immersion treatment, said solution mainly contains hydrofluoric acid or a liquid mixture of hydrofluoric acid and nitric acid.Type: ApplicationFiled: October 6, 2011Publication date: November 28, 2013Applicant: JFE STEEL CORPORATIONInventors: Tomohiro Ishii, Shin Ishikawa, Takumi Ujiro
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Publication number: 20130272912Abstract: An object is to provide a ferritic stainless steel having excellent oxidation resistance, while preventing a deterioration in formability, without adding expensive chemical elements such as Mo and W. Specifically, the ferritic stainless steel excellent in oxidation resistance having a chemical composition containing, by mass%, C: 0.015% or less, Si: 0.40% or more and 1.00% or less, Mn: 1.00% or less, P: 0.040% or less, S: 0.010% or less, Cr: 12.0% or more and 23.0% or less, N: 0.015% or less, Nb: 0.30% or more and 0.65% or less, Ti: 0.150% or less, Mo: 0.10% or less, W: 0.10% or less, Cu: less than 1.00%, Al: 0.20% or more and 1.00% or less, while the relationship Si?Al is satisfied, and the balance being Fe and inevitable impurities.Type: ApplicationFiled: October 12, 2011Publication date: October 17, 2013Applicant: JFE STEEL CORPORATIONInventors: Tetsuyuki Nakamura, Hiroki Ota, Takumi Ujiro
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Publication number: 20130196172Abstract: A stainless steel foil contains, in percent by mass, 0.05% or less of C, 2.0% or less of Si, 1.0% or less of Mn, 0.003% or less of S, 0.05% or less of P, 25.0% to 35.0% of Cr, 0.05% to 0.30% of Ni, 3.0% to 10.0% of Al, 0.10% or less of N, 0.02% or less of Ti, 0.02% or less of Nb, 0.02% or less of Ta, 0.005% to 0.20% of Zr, 0.02% or less of Ce, 0.03% to 0.20% of REM excluding Ce, 0.5% to 6.0% in total of at least one of Mo and W, and the balance being Fe and incidental impurities.Type: ApplicationFiled: March 18, 2011Publication date: August 1, 2013Applicant: JFE STEEL CORPORATIONInventors: Akito Mizutani, Kunio Fukuda, Shin Ishikawa, Atsutaka Honda, Yasuhiro Yamaguchi, Yasushi Kato, Hiroki Ota, Mitsuyuki Fujisawa, Takumi Ujiro, Hideaki Yamashita
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Publication number: 20130177837Abstract: An object is to provide at a low cost a metal sheet which can be ideally used as a separator of a proton-exchange membrane fuel cell and which has not only low contact resistance but also excellent durability in the environment in which the separator is used. Specifically, a metal sheet for a separator of a proton-exchange membrane fuel cell consists of a metal substrate on the surface of which a film made of a Sn alloy layer containing conducting particles is formed.Type: ApplicationFiled: April 21, 2011Publication date: July 11, 2013Applicant: JFE STEEL CORPORATIONInventors: Naoki Nishiyama, Shin Ishikawa, Takumi Ujiro, Yasushi Kato
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Patent number: 8440029Abstract: A stainless steel having good conductivity and ductility for use in a fuel cell separator is provided. In particular, the stainless steel has a composition of, in terms of % by mass, C: 0.01% or less, Si: 1.0% or less, Mn: 1.0% or less, S: 0.01% or less, P: 0.05% or less, Al: 0.20% or less, N: 0.02% or less, Cr: 20 to 40%, Mo: 4.0% or less, and at least one selected from Nb, Ti, and Zr: 0.05 to 0.60% in total, the balance being Fe and unavoidable impurities. At least one precipitate having an equivalent circle diameter of 0.1 ?m or more is present per 100 ?m2, a ratio of a thickness t (?m) to a maximum diameter Dmax (?m) of the precipitates satisfies formula (1) below 20?t/Dmax??(1) and the thickness is 200 ?m or less.Type: GrantFiled: July 26, 2010Date of Patent: May 14, 2013Assignee: JFE Steel CorporationInventors: Shinsuke Ide, Atsutaka Honda, Shin Ishikawa, Takumi Ujiro
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Publication number: 20130108945Abstract: The invention provides stainless steel for conductive members which exhibits excellent electrical conductivity (namely, low contact electric resistance), and a method for producing such stainless steel. In an exemplary embodiment of the method, stainless steel is dipped into a solution containing fluoride ions at a rate of dissolution of not less than 0.002 g/(m2·s) to less than 0.50 g/(m2·s), thereby incorporating fluorine into a passive film on the steel surface.Type: ApplicationFiled: January 20, 2010Publication date: May 2, 2013Applicant: JFE STEEL CORPORATIONInventors: Tomohiro Ishii, Shinsuke Ide, Shin Ishikawa, Yasushi Kato, Takumi Ujiro
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Patent number: 8383034Abstract: A ferritic stainless steel sheet for a water heater with excellent corrosion resistance of welds and toughness includes, in terms of mass %, 0.020% or less of C, 0.30 to 1.00% of Si, 1.00% or less of Mn, 0.040% or less of P, 0.010% or less of S, 20.0 to 28.0% of Cr, 0.6% or less of Ni, 0.03 to 0.15% of Al, 0.020% or less of N, 0.0020 to 0.0150% of O, 0.3 to 1.5% of Mo, 0.25 to 0.60% of Nb, and 0.05% or less of Ti, the remainder being composed of Fe and unavoidable impurities, and the ferritic stainless steel sheet satisfying the following formulae (1) and (2): 25?Cr+3.3Mo?30??(1) 0.35?Si+Al?0.85??(2) wherein Cr, Mo, Si, and Al represent the content (mass %) of Cr, Mo, Si, and Al, respectively.Type: GrantFiled: January 7, 2008Date of Patent: February 26, 2013Assignee: JFE Steel CorporationInventors: Kunio Fukuda, Yoshimasa Funakawa, Shuji Okada, Toshihiro Kasamo, Katsuhiro Kobori, Takumi Ujiro, Tomohiro Ishii
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Patent number: 8357247Abstract: A martensitic stainless steel, having high temper softening resistance, for disc brakes is provided. The martensitic stainless steel is not seriously softened by maintaining the steel at more than 600° C. The steel has a hardness of 32 or more or a hardness of 30 or more in HRC after the steel is tempered at 650° C. for one hour or tempered at 670° C. for one hour, respectively. In particular, the martensitic stainless steel for disc brakes contains less than 0.050 mass % carbon, 1.0 mass % or less silicon, 2.0 mass % or less manganese, 0.04 mass % or less phosphorus, 0.010 mass % or less sulfur, 0.2 mass % or less aluminum, more than 11.5 mass % to 15.0 mass % chromium, 0.5 mass % to 2.0 mass % nickel, more than 0.50 mass % to 4.0 mass %. copper, more than 0.08 mass % to 0.6 mass % niobium, and less than 0.09 mass % nitrogen, the remainder being iron and unavoidable impurities.Type: GrantFiled: April 23, 2004Date of Patent: January 22, 2013Assignee: JFE Steel CorporationInventors: Junichiro Hirasawa, Yoshihiro Ozaki, Takumi Ujiro, Osamu Furukimi
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Patent number: 8333849Abstract: A material for brake discs has temper softening resistance sufficient to maintain a hardness of HRC 31 or more after tempering at 700° C. for one hour. The low-carbon martensitic chromium-containing steel contains 0.02% to 0.10% of carbon and 0.02% to 0.10% of nitrogen, the total content of carbon and nitrogen being 0.08% to 0.16%; 0.5% or less of silicon; 0.1% or less of aluminum; 0.3% to 3.0% of manganese; 10.5% to 13.5% of chromium; 0.05% to 0.60% of niobium and 0.15% to 0.80% of vanadium, the total content of niobium and vanadium being 0.25% to 0.95%; 0.02% to 2.0% of nickel; and 1.5% or less of copper, and has an Fp value (=?230C+5Si?5Mn?6Cu+10Cr?12Ni+32Nb+22V+l2Mo+8W+10Ta+40A1?220N) of 80.0 to 96.0, a hardness after quenching of HRC 31 to 40, and a hardness after tempering at 700° C. for one hour of HRC 31 or more.Type: GrantFiled: April 23, 2009Date of Patent: December 18, 2012Assignee: JFE Steel CorporationInventors: Katsuhisa Yamauchi, Yasushi Kato, Takumi Ujiro, Takako Yamashita
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Publication number: 20120276472Abstract: A stainless steel for a fuel cell having good corrosion resistance throughout a wide potential range and a method for producing the same are provided. In particular, a coating having an intensity ratio [(OO/OH)/(Cr/Fe)] of 1.0 or more determined by X-ray photoelectron spectroscopy analysis is formed by performing an anodic electrolyzation treatment on a surface of a stainless steel in an electrolyte solution, the stainless steel containing 16% by mass or more of Cr and preferably having a composition that includes, in terms of percent by mass, C: 0.03% or less, Si: 1.0% or less, Mn: 1.0% or less, S: 0.01% or less, P: 0.05% or less, Al: 0.20% or less, N: 0.03% or less, Cr: 20 to 40%, at least one selected from Nb, Ti, and Zr, in total: 1.0% or less, and the balance being Fe and unavoidable impurities.Type: ApplicationFiled: July 22, 2010Publication date: November 1, 2012Applicant: JFE STEEL CORPORATIONInventors: Shinsuke Ide, Tomohiro Ishii, Naoki Nishiyama, Shin Ishikawa, Takumi Ujiro, Noriko Makiishi
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Publication number: 20120125724Abstract: A steel sheet for a brake disc contains, on a mass percent basis, 0.02% or more and less than 0.10% C, 0.6% or less Si, more than 0.5% and 2.0% or less Mn, 0.06% or less P, 0.01% or less S, 0.05% or less Al, 11.0% to 13.5% Cr, 0.01% to 0.30% Ni, 0.10% to 0.60% Nb, 0.03% or more and less than 0.10% N, more than 0.0010% and 0.0060% or less B, and the balance being Fe and incidental impurities, and the steel sheet after quenching has a hardness of 32 HRC to 40 HRC on a Rockwell hardness scale C (HRC).Type: ApplicationFiled: May 31, 2010Publication date: May 24, 2012Applicant: JFE STEEL CORPORATIONInventors: Katsuhisa Yamauchi, Mitsuyuki Fujisawa, Yasushi Kato, Hiroki Ota, Hideya Furusawa, Takumi Ujiro
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Publication number: 20120118442Abstract: A stainless steel having good conductivity and ductility for use in a fuel cell separator is provided. In particular, the stainless steel has a composition of, in terms of % by mass, C: 0.01% or less, Si: 1.0% or less, Mn: 1.0% or less, S: 0.01% or less, P: 0.05% or less, Al: 0.20% or less, N: 0.02% or less, Cr: 20 to 40%, Mo: 4.0% or less, and at least one selected from Nb, Ti, and Zr: 0.05 to 0.60% in total, the balance being Fe and unavoidable impurities. At least one precipitate having an equivalent circle diameter of 0.1 ?m or more is present per 100 ?m2, a ratio of a thickness t (?m) to a maximum diameter Dmax (?m) of the precipitates satisfies formula (1) below 20?t/Dmax??(1) and the thickness is 200 ?m or less.Type: ApplicationFiled: July 26, 2010Publication date: May 17, 2012Applicant: JFE Steel CorporationInventors: Shinsuke Ide, Atsutaka Honda, Shin Ishikawa, Takumi Ujiro