Patents by Inventor Shuji Kozawa
Shuji Kozawa 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: 11952650Abstract: A steel wire which has an excellent fatigue limit when made into a spring is provided. A chemical composition of the steel wire according to the present embodiment consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, N: 0.0070% or less, Ca: 0 to 0.0050%, and Nb: 0 to 0.020%, with the balance being Fe and impurities. In the steel wire, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 pieces/?m2.Type: GrantFiled: October 15, 2020Date of Patent: April 9, 2024Assignees: NIPPON STEEL CORPORATION, NIPPON STEEL SG WIRE CO., LTD.Inventors: Shinya Teramoto, Yutaka Neishi, Michimasa Aono, Shuji Kozawa, Satoru Mineta, Tatsuro Ochi, Shoichi Suzuki
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Publication number: 20240077123Abstract: A valve spring includes a nitrided layer, and a core portion that is further inward than the nitrided layer. A chemical composition of the core portion consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr: 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Ca: 0.0001 to 0.0050%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, and N: 0.0070% or less, with the balance being Fe and impurities. In the core portion, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 per ?m2, and in the core portion, a numerical proportion of Ca sulfides with respect to a total number of oxide-based inclusions and sulfide-based inclusions is 0.20% or less.Type: ApplicationFiled: October 15, 2020Publication date: March 7, 2024Inventors: Shinya TERAMOTO, Yutaka NEISHI, Michimasa AONO, Shuji KOZAWA, Fumio TAKAHASHI, Shigekazu NISHIMOTO, Mitsuhiro KONDO, Tatsuro OCHI, Shoichi SUZUKI
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Publication number: 20230392244Abstract: A steel wire which has an excellent fatigue limit when made into a spring is provided. A chemical composition of the steel wire according to the present embodiment consists of, in mass %, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, S: 0.020% or less, Cr 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, N: 0.0070% or less, Ca: 0 to 0.0050%, and Nb: 0 to 0.020%, with the balance being Fe and impurities. In the steel wire, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 pieces/?m2.Type: ApplicationFiled: October 15, 2020Publication date: December 7, 2023Inventors: Shinya TERAMOTO, Yutaka NEISHI, Michimasa AONO, Shuji KOZAWA, Satoru MINETA, Tatsuro OCHI, Shoichi SUZUKI
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Publication number: 20230296152Abstract: A damper spring having an excellent fatigue limit is provided. A damper spring according to the present embodiment includes a nitrided layer formed in an outer layer, and a core portion that is further inward than the nitrided layer. The chemical composition of the core portion consists of, in mass%, C: 0.53 to 0.59%, Si: 2.51 to 2.90%, Mn: 0.70 to 0.85%, P: 0.020% or less, 5: 0.020% or less, Cr: 1.40 to 1.70%, Mo: 0.17 to 0.53%, V: 0.23 to 0.33%, Cu: 0.050% or less, Ni: 0.050% or less, Al: 0.0050% or less, Ti: 0.050% or less, N: 0.0070% or less, and Nb: 0 to 0.020%, with the balance being Fe and impurities. In the core portion, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 500 to 8000 pieces/?m2.Type: ApplicationFiled: October 15, 2020Publication date: September 21, 2023Inventors: Shinya TERAMOTO, Yutaka NEISHI, Michimasa AONO, Shuji KOZAWA, Yoichi OI, Naoki TAKABAYASHI, Junji TANAKA, Fumio TAKAHASHI, Shigekazu NISHIMOTO, Mitsuhiro KONDO, Tatsuro OCHI, Shoichi SUZUKI
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Patent number: 11118251Abstract: A rolled wire rod for spring steel contains, as a chemical composition, by mass %: C: 0.42% to 0.60%; Si: 0.90% to 3.00%; Mn: 0.10% to 1.50%; Cr: 0.10% to 1.50%; B: 0.0010% to 0.0060%; N: 0.0010% to 0.0070%; Mo: 0% to 1.00%; V: 0% to 1.00%; Ni: 0% to 1.00%; Cu: 0% to 0.50%; Al: 0% to 0.100%; Ti: 0% to 0.100%; Nb: 0% to 0.100%; P: limited to less than 0.020%; S: limited to less than 0.020%; and a remainder including Fe and impurities, the carbon equivalent (Ceq) is 0.75% to 1.00%, the area fraction of tempered martensite and bainite included in a microstructure is 90% or greater, the tensile strength is 1,350 MPa or less, and the reduction of area is 40% or greater.Type: GrantFiled: June 15, 2018Date of Patent: September 14, 2021Assignee: NIPPON STEEL CORPORATIONInventors: Takahisa Suzuki, Yutaka Neishi, Shuji Kozawa
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Patent number: 10724125Abstract: Spring steel includes: as a chemical composition, by mass %, C: 0.40% to 0.60%, Si: 0.90% to 2.50%, Mn: 0.20% to 1.20%, Cr: 0.15% to 2.00%, Ni: 0.10% to 1.00%, Ti: 0.030% to 0.100%, B: 0.0010% to 0.0060%, N: 0.0010% to 0.0070%, Cu: 0% to 0.50%, Mo: 0% to 1.00%, V: 0% to 0.50%, Nb: 0% to 0.10%, P: limited to less than 0.020%, S: limited to less than 0.020%, Al: limited to less than 0.050%, and a remainder including Fe and impurities, in a case where [Ti] represents a Ti content and [N] represents a N content by mass %, the chemical composition satisfies ([Ti]?3.43×[N])>0.03, and a total number density of a Ti carbide and a Ti carbonitride having a diameter of 5 nm to 100 nm is more than 50 piece/?m3.Type: GrantFiled: May 13, 2016Date of Patent: July 28, 2020Assignee: NIPPON STEEL CORPORATIONInventors: Takahisa Suzuki, Manabu Kubota, Shuji Kozawa, Hirotsugu Miyamoto
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Publication number: 20200095663Abstract: A rolled wire rod for spring steel contains, as a chemical composition, by mass %: C: 0.42% to 0.60%; Si: 0.90% to 3.00%; Mn: 0.10% to 1.50%; Cr: 0.10% to 1.50%; B: 0.0010% to 0.0060%; N: 0.0010% to 0.0070%; Mo: 0% to 1.00%; V: 0% to 1.00%; Ni: 0% to 1.00%; Cu: 0% to 0.50%; Al: 0% to 0.100%; Ti: 0% to 0.100%; Nb: 0% to 0.100%; P: limited to less than 0.020%; S: limited to less than 0.020%; and a remainder including Fe and impurities, the carbon equivalent (Ceq) is 0.75% to 1.00%, the area fraction of tempered martensite and bainite included in a microstructure is 90% or greater, the tensile strength is 1,350 MPa or less, and the reduction of area is 40% or greater.Type: ApplicationFiled: June 15, 2018Publication date: March 26, 2020Applicant: NIPPON STEEL CORPORATIONInventors: Takahisa SUZUKI, Yutaka NEISHI, Shuji KOZAWA
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Publication number: 20180142333Abstract: Spring steel includes: as a chemical composition, by mass %, C: 0.40% to 0.60%, Si: 0.90% to 2.50%, Mn: 0.20% to 1.20%, Cr: 0.15% to 2.00%, Ni: 0.10% to 1.00%, Ti: 0.030% to 0.100%, B: 0.0010% to 0.0060%, N: 0.0010% to 0.0070%, Cu: 0% to 0.50%, Mo: 0% to 1.00%, V: 0% to 0.50%, Nb: 0% to 0.10%, P: limited to less than 0.020%, S: limited to less than 0.020%, Al: limited to less than 0.050%, and a remainder including Fe and impurities, in a case where [Ti] represents a Ti content and [N] represents a N content by mass %, the chemical composition satisfies ([Ti]-3.43×[N])>0.03, and a total number density of a Ti carbide and a Ti carbonitride having a diameter of 5 nm to 100 nm is more than 50 piece/?m3.Type: ApplicationFiled: May 13, 2016Publication date: May 24, 2018Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Takahisa SUZUKI, Manabu KUBOTA, Shuji KOZAWA, Hirotsugu MIYAMOTO
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Patent number: 9777343Abstract: The present invention is steel for surface hardening for machine structural use which contains, by mass %, C: 0.3 to 0.6%, Si: 0.02 to 2.0%, Mn: 0.35 to less than 1.5%, and Al: 0.01 to 0.5%, is restricted to B: less than 0.0003%, S: 0.0001 to 0.021%, N: 0.003 to 0.0055%, P: 0.0001 to 0.03%, and O: 0.0001 to 0.0050%, has a ratio Mn/S of Mn and S satisfying 70 to 30,000, has a balance of Fe and unavoidable impurities, and, when nitrided, then induction hardened, has a surface hardenability of a Vicker's hardness when tempered at 300° C. of 650 or more.Type: GrantFiled: April 14, 2014Date of Patent: October 3, 2017Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Atsushi Mizuno, Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa
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Patent number: 9469883Abstract: A carburized steel part having excellent low cycle bending fatigue strength which is comprised of a steel material which contains, by mass %, C: 0.1 to 0.6%, Si: 0.01 to 1.5%, Mn: 0.3 to 2.0, P: 0.02% or less, S: 0.001 to 0.15%, N: 0.001 to 0.03%, Al: 0.001 to 0.06%, and O: 0.005% or less and has a balance of substantially iron and unavoidable impurities and which is carburized and quenched, and then tempered, which steel part has a surface hardness of HV550 to HV800 and a core hardness of HV400 to HV500.Type: GrantFiled: August 30, 2013Date of Patent: October 18, 2016Assignees: NIPPON STEEL & SUMITOMO METAL CORPORATION, SANYO SPECIAL STEEL CO., LTD.Inventors: Shuji Kozawa, Manabu Kubota, Osamu Kada, Motohiro Nishikawa, Takashi Tanaka, Norimasa Tsunekage
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Publication number: 20160060744Abstract: There is provided a case-hardening steel in which in inclusion evaluation using an extreme value statistical method, when an estimated area S is 30,000 mm2, an estimated value of the maximum size (?area)S of sulfide-based inclusions present in the estimated area S is 49 ?m or less and an estimated value of the maximum size (?area)Ox of oxide-based inclusions present in the estimated area S is 80 ?m or less, and the number of sulfide-based inclusions having a length of more than 20 ?m and a thickness of more than 2 ?m per 1 mm2 is limited to 200 or less,Type: ApplicationFiled: April 16, 2014Publication date: March 3, 2016Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Manabu KUBOTA, Shuji KOZAWA
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Patent number: 9156231Abstract: Steel for machine structure use for surface hardening containing, by mass %, C: 0.3 to 0.6%, Si: 0.02 to 2.0%, Mn: 1.5% to 3.0%, W: 0.0025 to 0.5%, Al: 0.001 to 0.5%, N: 0.003 to 0.02%, S: 0.0001 to 0.025%, P: 0.0001 to 0.03%, and O: 0.0001 to 0.0050%, having an Mn/S of 70 to 30000, and having a balance of substantially Fe and unavoidable impurities.Type: GrantFiled: March 18, 2013Date of Patent: October 13, 2015Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Atsushi Mizuno, Masayuki Hashimura, Hajime Saitoh, Shuji Kozawa, Kei Miyanishi
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Patent number: 9139894Abstract: This steel for a machine structure contains, in mass %: C: 0.40% to less than 0.75%; Si: 0.01% to 3.0%; Mn: 0.1% to 1.8%; S: 0.001% to 0.1%; Al: more than 0.1% and not more than 1.0%; N: 0.001% to 0.02%; and P: limited to not more than 0.05%, with a balance including Fe and inevitable impurities, in which the steel satisfies 139.38?214×[C]+30.6×[Si]+42.8×[Mn]?14.7×[Al]?177 and 0.72?[C]+1/7×[Si]+1/5×[Mn]<1.539.Type: GrantFiled: July 11, 2011Date of Patent: September 22, 2015Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Toshiharu Aiso, Suguru Yoshida, Manabu Kubota, Kei Miyanishi, Shuji Kozawa
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Publication number: 20140251507Abstract: The present invention is steel for surface hardening for machine structural use which contains, by mass %, C: 0.3 to 0.6%, Si: 0.02 to 2.0%, Mn: 0.35 to less than 1.5%, and Al: 0.01 to 0.5%, is restricted to B: less than 0.0003%, S: 0.0001 to 0.021%, N: 0.003 to 0.0055%, P: 0.0001 to 0.03%, and 0:0.0001 to 0.0050%, has a ratio Mn/S of Mn and S satisfying 70 to 30,000, has a balance of Fe and unavoidable impurities, and, when nitrided, then induction hardened, has a surface hardenability of a Vicker's hardness when tempered at 300° C. of 650 or more.Type: ApplicationFiled: April 14, 2014Publication date: September 11, 2014Applicant: Nippon Steel & Sumitomo Metal CorporationInventors: Atsushi Mizuno, Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa
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Patent number: 8821652Abstract: Steel for induction hardening wherein coarsening of austenite crystal grains can be prevented even at a high temperature of over 1100° C. such as which occurs at projecting parts of steel parts at the time of induction hardening, the steel for induction hardening characterized by containing, by mass %, C: 0.35 to 0.6%, Si: 0.01 to 1%, Mn: 0.2 to 1.8%, S: 0.001 to 0.15%, Al: 0.001 to 1%, Ti: 0.05 to 0.2%, and Nb: 0.001 to 0.04%, restricting N: 0.0060% or less, P: 0.025% or less, and O: 0.0025% or less, satisfying Nb/Ti?0.015, and having a balance of iron and unavoidable impurities.Type: GrantFiled: October 7, 2010Date of Patent: September 2, 2014Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Shuji Kozawa, Manabu Kubota
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Patent number: 8802005Abstract: The present invention is steel for surface hardening for machine structural use which contains, by mass %, C: 0.3 to 0.6%, Si: 0.02 to 2.0%, Mn: 0.35 to less than 1.5%, and Al: 0.01 to 0.5%, is restricted to B: less than 0.0003%, S: 0.0001 to 0.021%, N: 0.003 to 0.0055%, P: 0.0001 to 0.03%, and O: 0.0001 to 0.0050%, has a ratio Mn/S of Mn and S satisfying 70 to 30,000, has a balance of Fe and unavoidable impurities, and, when nitrided, then induction hardened, has a surface hardenability of a Vicker's hardness when tempered at 300° C. of 650 or more.Type: GrantFiled: January 15, 2010Date of Patent: August 12, 2014Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Atsushi Mizuno, Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa
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Patent number: 8733199Abstract: A method of manufacturing a gear, and the resulting gear, the method resulting such that the surface layer portions of the tooth portions and a tooth root portion are made to be a carburized layer, the remaining portion of the tooth portions and a portion of a disk portion lying below the carburized layer be a quench-hardened layer, and a region of the disk portion lying deeper than the quench-hardened layer be an unquenched layer. The gear is manufactured using raw material steel having the following chemical composition: C: 0.1% to 0.40% (% by mass), Si: 0.35% to 3.0%, Mn: 0.1% to 3.0%, Cr: less than 0.2%, Mo: 0.1% or less, P: 0.03% or less, S: 0.15% or less, Al: 0.05% or less, N: 0.03% or less, and Fe and unavoidable impurities.Type: GrantFiled: April 8, 2011Date of Patent: May 27, 2014Assignees: Aisin AW Co., Ltd., Nippon Steel CorporationInventors: Koji Obayashi, Keita Taguchi, Susumu Kato, Shuji Kozawa, Manabu Kubota, Yuji Adachi, Hirokazu Sato
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Patent number: 8673094Abstract: A case hardening steel includes by mass %, C: 0.1% to 0.5%, Si: 0.01% to 1.5%, Mn: 0.3% to 1.8%, S: 0.001% to 0.15%, Cr: 0.4% to 2.0%, Ti: 0.05% to 0.2%, Al: limited to 0.2% or less, N: limited to 0.0050% or less, P: limited to 0.025% or less, O: limited to 0.0025% or less, and the balance of Fe and inevitable impurities, wherein the number d of sulfide having an equivalent circle diameter more than 5 ?m per 1 mm2 and a mass percentage [S] of S satisfy: d?500×[S]+1.Type: GrantFiled: October 5, 2011Date of Patent: March 18, 2014Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa, Manabu Kubota, Tatsuro Ochi
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Publication number: 20130340895Abstract: A carburized steel part having excellent low cycle bending fatigue strength which is comprised of a steel material which contains, by mass %, C: 0.1 to 0.6%, Si: 0.01 to 1.5%, Mn: 0.3 to 2.0, P: 0.02% or less, S: 0.001 to 0.15%, N: 0.001 to 0.03%, Al: 0.001 to 0.06%, and O: 0.005% or less and has a balance of substantially iron and unavoidable impurities and which is carburized and quenched, and then tempered, which steel part has a surface hardness of HV550 to HV800 and a core hardness of HV400 to HV500.Type: ApplicationFiled: August 30, 2013Publication date: December 26, 2013Applicants: SANYO SPECIAL STEEL CO., LTD., NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Shuji KOZAWA, Manabu KUBOTA, Osamu KADA, Motohiro NISHIKAWA, Takashi TANAKA, Norimasa TSUNEKAGE
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Patent number: 8535459Abstract: The present invention provides a steel material for hardening, including chemical components, by mass %, of: C: 0.15 to 0.60%; Si: 0.01 to 1.5%; Mn: 0.05 to 2.5%; P: 0.005 to 0.20%; S: 0.001 to 0.35%; Al: over 0.06 to 0.3%; and total N: 0.006 to 0.03%, with a balance including Fe and inevitable impurities including B of not more than 0.0004%, in which a hardness R at a position 5 mm away from a quenching end measured through a Jominy-type end-quenching method specified in JIS G 0561, and a calculation hardness H at a position 4.763 mm away from the quenching end satisfy the following Equation (1). H×0.948?R?H×1.Type: GrantFiled: May 17, 2011Date of Patent: September 17, 2013Assignee: Nippon Steel & Sumitomo Metal CorporationInventors: Kei Miyanishi, Manabu Kubota, Shuji Kozawa