Patents by Inventor Mitsuhiro Okatsu
Mitsuhiro Okatsu 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: 12227815Abstract: A seamless steel pipe of the present invention is a seamless steel pipe having a composition that includes, in mass %, C: 0.02 to 0.12%, Si: 0.010 to 1.00%, Mn: 0.10 to 2.00%, P: 0.050% or less, S: 0.004% or less, Al: 0.010 to 0.100%, Cu: 0.03 to 0.80%, Ni: 0.02 to 0.50%, Cr: 0.55 to 1.00%, Sb: 0.005 to 0.20%, and the balance Fe and incidental impurities, and satisfying the following formula (1), 1.7×Cu*+11×Cr*+3.8×Sb*?13.5??(1), where Cu*, Cr*, and Sb* represent average concentrations of Cu, Cr, and Sb, respectively, in mass %, as measured in a region 0.5 to 2.0 mm away from an outer surface of the steel pipe, the seamless steel pipe having a yield strength of 230 MPa or more, and a tensile strength of 380 MPa or more.Type: GrantFiled: June 12, 2020Date of Patent: February 18, 2025Assignee: JFE Steel CorporationInventors: Masao Yuga, Hiroyuki Takai, Yasumasa Takemura, Mitsuhiro Okatsu
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Patent number: 12227816Abstract: Provided herein is a high-strength seamless steel pipe, and a method for manufacturing same. A high-strength seamless steel pipe of the present invention has a yield strength of 758 MPa or more, and a KILIMIT value of 23.0 MPa?m or more as an evaluation index of sulfide stress corrosion cracking resistance.Type: GrantFiled: November 24, 2020Date of Patent: February 18, 2025Assignee: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Toshiharu Hirama
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Patent number: 12129954Abstract: A seamless steel pipe of the present invention is a seamless steel pipe having a composition including, in mass %, C: 0.01 to 0.12%, Si: 0.01 to 0.8%, Mn: 0.10 to 2.00%, P: 0.050% or less, S: 0.040% or less, Al: 0.010 to 0.100%, Cu: 0.03 to 0.80%, Ni: 0.01 to 0.50%, Mo: 0.01 to 0.20%, Sb: 0.002 to 0.50%, Cr: 0.004% or less, W: 0.002% or less, and the balance Fe and incidental impurities, and a structure including a ferrite phase having an area percentage of 50 to 65%, a pearlite phase having an area percentage of 2% or less, and one or both of a bainite phase and a martensitic phase representing the remainder, the seamless steel pipe having a yield strength of 230 MPa or more, and a tensile strength of 380 MPa or more.Type: GrantFiled: June 12, 2020Date of Patent: October 29, 2024Assignee: JFE Steel CorporationInventors: Hiroyuki Takai, Mitsuhiro Okatsu, Yasumasa Takemura, Tatsuo Koide
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Publication number: 20230107887Abstract: Provided herein is a stainless steel seamless pipe for oil country tubular goods. A method for manufacturing such a stainless steel seamless pipe is also provided. The stainless steel seamless pipe has: a composition that contains, in mass %, C: 0.10% or less, Si: 0.5% or less, Mn: 0.05 to 0.50%, P: 0.030% or less, S: 0.005% or less, O: 0.0040% or less, Ni: 3.0 to 8.0%, Cr: 10.0 to 14.0%, Mo: 0.5 to 2.8%, Al: 0.1% or less, V: 0.005 to 0.2%, N: 0.10% or less, Cu: 0.01 to 1.0%, Co: 0.01 to 1.0%, and Ca: 0.0005 to 0.0030%, and in which the balance is Fe and incidental impurities; a microstructure containing at most 20 non-metallic inclusions having a predetermined composition ratio of CaO and Al2O3 and a major axis of 5 ?m or more per 100 mm2; and a yield stress of 655 MPa or more.Type: ApplicationFiled: March 25, 2021Publication date: April 6, 2023Applicant: JFE Steel CorporationInventors: Mami Endo, Kenichiro Eguchi, Mitsuhiro Okatsu, Masao Yuga
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Publication number: 20230055650Abstract: Provided herein is a high-strength seamless steel pipe, and a method for manufacturing same. A high-strength seamless steel pipe of the present invention has a yield strength of 758 MPa or more, and a KILIMIT value of 23.0 MPa?m or more as an evaluation index of sulfide stress corrosion cracking resistance.Type: ApplicationFiled: November 24, 2020Publication date: February 23, 2023Applicant: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Toshiharu Hirama
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Publication number: 20230023397Abstract: Provided herein is a high-strength seamless steel pipe, and a method for manufacturing same. A high-strength seamless steel pipe of the present invention has a steel microstructure with a prior austenite grain size of 11.0 or more in terms of a grain size number in compliance with ASTM E112, and has a yield strength of 862 MPa or more and 965 MPa or less.Type: ApplicationFiled: November 24, 2020Publication date: January 26, 2023Applicant: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Toshiharu Hirama
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Publication number: 20220411890Abstract: A seamless steel pipe of the present invention is a seamless steel pipe having a composition that includes, in mass %, C: 0.02 to 0.12%, Si: 0.010 to 1.00%, Mn: 0.10 to 2.00%, P: 0.050% or less, S: 0.004% or less, Al: 0.010 to 0.100%, Cu: 0.03 to 0.80%, Ni: 0.02 to 0.50%, Cr: 0.55 to 1.00%, Sb: 0.005 to 0.20%, and the balance Fe and incidental impurities, and satisfying the following formula (1), 1.7×Cu*+11×Cr*+3.8×Sb*?13.5 ??(1), where Cu*, Cr*, and Sb* represent average concentrations of Cu, Cr, and Sb, respectively, in mass %, as measured in a region 0.5 to 2.0 mm away from an outer surface of the steel pipe, the seamless steel pipe having a yield strength of 230 MPa or more, and a tensile strength of 380 MPa or more.Type: ApplicationFiled: June 12, 2020Publication date: December 29, 2022Applicant: JFE Steel CorporationInventors: Masao Yuga, Hiroyuki Takai, Yasumasa Takemura, Mitsuhiro Okatsu
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Patent number: 11505842Abstract: Provided herein is a low-alloy high-strength seamless steel pipe. The steel pipe of the present invention has a composition that contains, in mass %, C: 0.20 to 0.50%, Si: 0.01 to 0.35%, Mn: 0.45 to 1.5%, P: 0.020% or less, S: 0.002% or less, 0: 0.003% or less, Al: 0.01 to 0.08%, Cu: 0.02 to 0.09%, Cr: 0.35 to 1.1%, Mo: 0.05 to 0.35%, B: 0.0010 to 0.0030%, Ca: 0.0010 to 0.0030%, Mg: 0.001% or less, and N: 0.005% or less, and in which the balance is Fe and incidental impurities. The steel pipe has a microstructure in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by predefined formulae is 20 or less per 100 mm2, and in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by other predefined formulae is 50 or less per 100 mm2.Type: GrantFiled: December 6, 2018Date of Patent: November 22, 2022Assignee: JFE STEEL CORPORATIONInventors: Mitsuhiro Okatsu, Masao Yuga, Yoichi Ito
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Publication number: 20220364671Abstract: A seamless steel pipe of the present invention is a seamless steel pipe having a composition including, in mass %, C: 0.01 to 0.12%, Si: 0.01 to 0.8%, Mn: 0.10 to 2.00%, P: 0.050% or less, S: 0.040% or less, Al: 0.010 to 0.100%, Cu: 0.03 to 0.80%, Ni: 0.01 to 0.50%, Mo: 0.01 to 0.20%, Sb: 0.002 to 0.50%, Cr: 0.004% or less, W: 0.002% or less, and the balance Fe and incidental impurities, and a structure including a ferrite phase having an area percentage of 50 to 65%, a pearlite phase having an area percentage of 2% or less, and one or both of a bainite phase and a martensitic phase representing the remainder, the seamless steel pipe having a yield strength of 230 MPa or more, and a tensile strength of 380 MPa or more.Type: ApplicationFiled: June 12, 2020Publication date: November 17, 2022Applicant: JFE Steel CorporationInventors: Hiroyuki Takai, Mitsuhiro Okatsu, Yasumasa Takemura, Tatsuo Koide
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Patent number: 11453924Abstract: Provided herein is a low-alloy high-strength seamless steel pipe. The steel pipe of the present invention has a composition that contains, in mass %, C: 0.25 to 0.50%, Si: 0.01 to 0.40%, Mn: 0.3 to 1.5%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.080%, Cu: 0.02 to 0.09%, Cr: 0.5 to 0.8%, Mo: 0.5 to 1.3%, Nb: 0.005 to 0.05%, B: 0.0005 to 0.0040%, Ca: 0.0010 to 0.0020%, Mg: 0.001% or less, and N: 0.005% or less, and in which the balance is Fe and incidental impurities. The steel pipe has a microstructure in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by predefined formulae is 10 or less per 100 mm2, and in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by other predefined formulae is 30 or less per 100 mm2.Type: GrantFiled: December 6, 2018Date of Patent: September 27, 2022Assignee: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Yoichi Ito
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Patent number: 11414733Abstract: Provided herein is a low-alloy high-strength seamless steel pipe. The steel pipe of the present invention has a composition that contains, in mass %, C: 0.25 to 0.50%, Si: 0.01 to 0.40%, Mn: 0.45 to 0.90%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.080%, Cu: 0.02 to 0.09%, Cr: 0.9 to 1.5%, Mo: 1.4 to 2.0%, Nb: 0.005 to 0.05%, B: 0.0005 to 0.0040%, Ca: 0.0010 to 0.0020%, Mg: 0.001% or less, and N: 0.005% or less, and in which the balance is Fe and incidental impurities. The steel pipe has a microstructure in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by predefined formulae is 5 or less per 100 mm2, and in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by other predefined formulae is 20 or less per 100 mm2.Type: GrantFiled: December 6, 2018Date of Patent: August 16, 2022Assignee: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Yoichi Ito
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Patent number: 11313007Abstract: Provided herein is a high-strength seamless steel pipe containing a particular chemical composition. The volume fraction of tempered martensite is 90% or more in terms of a volume fraction. The number of nitride inclusions with a particle diameter of 4 ?m or more is 50 or less per 100 mm2, the number of nitride inclusions with a particle diameter of less than 4 ?m is 500 or less per 100 mm2, the number of oxide inclusions with a particle diameter of 4 ?m or more is 40 or less per 100 mm2, and the number of oxide inclusions with a particle diameter of less than 4 ?m is 400 or less per 100 mm2 in a cross section perpendicular to a rolling direction.Type: GrantFiled: September 13, 2017Date of Patent: April 26, 2022Assignee: JFE Steel CorporationInventors: Masao Yuga, Mitsuhiro Okatsu
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Patent number: 11186885Abstract: The high-strength seamless steel pipe has a volume fraction of tempered martensite of 95% or more, and a prior austenite size number of 8.5 or more, and contains nitride inclusions having a size of 4 ?m or more and whose number is 100 or less per 100 mm2, nitride inclusions having a size of less than 4 ?m and whose number is 700 or less per 100 mm2, oxide inclusions having a size of 4 ?m or more and whose number is 60 or less per 100 mm2, and oxide inclusions having a size of less than 4 ?m and whose number is 500 or less per 100 mm2, in a cross section perpendicular to a rolling direction.Type: GrantFiled: October 18, 2016Date of Patent: November 30, 2021Assignee: JFE Steel CorporationInventors: Masao Yuga, Mitsuhiro Okatsu, Hiroki Ota
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Publication number: 20210363620Abstract: Provided herein is a low-alloy high-strength seamless steel pipe. The steel pipe of the present invention has a composition that contains, in mass %, C: 0.25 to 0.50%, Si: 0.01 to 0.40%, Mn: 0.45 to 0.90%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.080%, Cu: 0.02 to 0.09%, Cr: 0.9 to 1.5%, Mo: 1.4 to 2.0%, Nb: 0.005 to 0.05%, B: 0.0005 to 0.0040%, Ca: 0.0010 to 0.0020%, Mg: 0.001% or less, and N: 0.005% or less, and in which the balance is Fe and incidental impurities. The steel pipe has a microstructure in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by predefined formulae is 5 or less per 100 mm2, and in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by other predefined formulae is 20 or less per 100 mm2.Type: ApplicationFiled: December 6, 2018Publication date: November 25, 2021Applicant: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Yoichi Ito
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Patent number: 11111566Abstract: The steel pipe of the present invention is a low alloy high strength seamless steel pipe for oil country tubular goods including a composition containing, in terms of mass %, C: 0.23 to 0.27%, Si: 0.01 to 0.35%, Mn: 0.45 to 0.70%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.080%, Cu: 0.02 to 0.09%, Cr: 0.8 to 1.5%, Mo: 0.5 to 1.0%, Nb: 0.02 to 0.05%, B: 0.0015 to 0.0030%, Ti: 0.005 to 0.020%, and N: 0.005% or less, and having a ratio of the Ti content to the N content (Ti/N) of 3.0 to 4.0, with the balance being Fe and inevitable impurities, the steel pipe having a ratio of a stress at a strain of 0.7% to a stress at a strain of 0.4% in a stress-strain curve of 1.02 or less and a yield strength of 655 MPa or more.Type: GrantFiled: August 22, 2018Date of Patent: September 7, 2021Assignee: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Hiroki Ota, Kazuki Fujimura
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Patent number: 10975450Abstract: A low alloy high strength thick-walled seamless steel pipe for oil country tubular goods is provided having a wall thickness of 40 mm or more and a yield strength of 758 MPa or more, the steel pipe including a composition containing, in terms of mass %, C: 0.25 to 0.31%, Si: 0.01 to 0.35%, Mn: 0.55 to 0.70%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.040%, Cu: 0.02 to 0.09%, Cr: 0.8 to 1.5%, Mo: 0.9 to 1.6%, V: 0.04 to 0.10%, Nb: 0.005 to 0.05%, B: 0.0015 to 0.0030%, Ti: 0.005 to 0.020%, and N: 0.005% or less, and having Ti/N of 3.0 to 4.0, with the balance being Fe and inevitable impurities, wherein a cumulative frequency rate at a measurement point at which a Mo segregation degree by a predetermined expression is 1.5 or more is 1% or less.Type: GrantFiled: November 18, 2016Date of Patent: April 13, 2021Assignee: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Kenichiro Eguchi, Haruo Nakamichi
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Publication number: 20210071275Abstract: Provided herein is a low-alloy high-strength seamless steel pipe. The steel pipe of the present invention has a composition that contains, in mass %, C: 0.25 to 0.50%, Si: 0.01 to 0.40%, Mn: 0.3 to 1.5%, P: 0.010% or less, S: 0.001% or less, O: 0.0015% or less, Al: 0.015 to 0.080%, Cu: 0.02 to 0.09%, Cr: 0.5 to 0.8%, Mo: 0.5 to 1.3%, Nb: 0.005 to 0.05%, B: 0.0005 to 0.0040%, Ca: 0.0010 to 0.0020%, Mg: 0.001% or less, and N: 0.005% or less, and in which the balance is Fe and incidental impurities. The steel pipe has a microstructure in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by predefined formulae is 10 or less per 100 mm2, and in which the number of oxide-base nonmetallic inclusions satisfying the composition ratios represented by other predefined formulae is 30 or less per 100 mm2.Type: ApplicationFiled: December 6, 2018Publication date: March 11, 2021Applicant: JFE Steel CorporationInventors: Mitsuhiro Okatsu, Masao Yuga, Yoichi Ito
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Patent number: 10920297Abstract: A seamless steel pipe having a specific chemical composition. A ratio of Ti to N is in a range of 2.0 to 5.0. The steel pipe has a microstructure including tempered martensite having a volume ratio of 95% or more, and prior austenite grains having a grain size number of 8.5 or more. In a cross-section perpendicular to a rolling direction of the steel pipe a number of nitride-based inclusions having a particle size of 4 ?m or more is 100 or less per 100 mm2, a number of nitride-based inclusions having a particle size of less than 4 ?m is 1000 or less per 100 mm2, a number of oxide-based inclusions having a particle size of 4 ?m or more is 40 or less per 100 mm2, and a number of oxide-based inclusions having a particle size of less than 4 ?m is 400 or less per 100 mm2.Type: GrantFiled: August 20, 2015Date of Patent: February 16, 2021Assignee: JFE STEEL CORPORATIONInventors: Masao Yuga, Yasuhide Ishiguro, Mitsuhiro Okatsu, Seiji Nabeshima, Hiroki Ota
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Patent number: 10876182Abstract: A high-strength seamless steel pipe for oil country tubular goods comprising, by mass %, C: 0.20% to 0.50%, Si: 0.05% to 0.40%, Mn: 0.3% to 0.9%, P: 0.015% or less, S: 0.005% or less, Al: 0.005% to 0.1%, N: 0.006% or less, Mo: more than 1.0% to 3.0% or less, V: 0.01% to less than 0.05%, Nb: 0.001% to less than 0.01%, B: 0.0003% to 0.0030%, O: 0.0030% or less, and Ti: 0.003% to 0.025%, and wherein Ti/N: 2.0 to 5.0 is satisfied, a volume fraction of a tempered martensitic is 95% or more, prior austenite grains have a grain size number of 8.Type: GrantFiled: September 10, 2015Date of Patent: December 29, 2020Assignee: JFE STEEL CORPORATIONInventors: Masao Yuga, Yasuhide Ishiguro, Seiji Nabeshima, Mitsuhiro Okatsu, Hiroki Ota
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Patent number: 10844453Abstract: A high-strength seamless steel pipe for oil country tubular goods comprising, by mass %, C: 0.20% to 0.50%, Si: 0.05% to 0.40%, Mn: more than 0.6% to 1.5% or less, P: 0.015% or less, S: 0.005% or less, Al: 0.005% to 0.1%, N: 0.006% or less, Mo: more than 1.0% to 3.0% or less, V: 0.05% to 0.3%, Nb: 0.001% to 0.020%, B: 0.0003% to 0.0030%, O: 0.0030% or less, and Ti: 0.003% to 0.025%, and wherein Ti/N: 2.0 to 5.0 is satisfied, a volume fraction of a tempered martensitic is 95% or more, prior austenite grains have a grain size number of 8.Type: GrantFiled: September 10, 2015Date of Patent: November 24, 2020Assignee: JFE Steel CorporationInventors: Masao Yuga, Yasuhide Ishiguro, Seiji Nabeshima, Mitsuhiro Okatsu, Hiroki Ota