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).

  • Patent number: 10724125
    Abstract: 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: Grant
    Filed: May 13, 2016
    Date of Patent: July 28, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Takahisa Suzuki, Manabu Kubota, Shuji Kozawa, Hirotsugu Miyamoto
  • Publication number: 20200095663
    Abstract: 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: Application
    Filed: June 15, 2018
    Publication date: March 26, 2020
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Takahisa SUZUKI, Yutaka NEISHI, Shuji KOZAWA
  • Publication number: 20180142333
    Abstract: 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: Application
    Filed: May 13, 2016
    Publication date: May 24, 2018
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Takahisa SUZUKI, Manabu KUBOTA, Shuji KOZAWA, Hirotsugu MIYAMOTO
  • Patent number: 9777343
    Abstract: 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: Grant
    Filed: April 14, 2014
    Date of Patent: October 3, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Atsushi Mizuno, Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa
  • Patent number: 9469883
    Abstract: 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: Grant
    Filed: August 30, 2013
    Date of Patent: October 18, 2016
    Assignees: NIPPON STEEL & SUMITOMO METAL CORPORATION, SANYO SPECIAL STEEL CO., LTD.
    Inventors: Shuji Kozawa, Manabu Kubota, Osamu Kada, Motohiro Nishikawa, Takashi Tanaka, Norimasa Tsunekage
  • Publication number: 20160060744
    Abstract: 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: Application
    Filed: April 16, 2014
    Publication date: March 3, 2016
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Manabu KUBOTA, Shuji KOZAWA
  • Patent number: 9156231
    Abstract: 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: Grant
    Filed: March 18, 2013
    Date of Patent: October 13, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Atsushi Mizuno, Masayuki Hashimura, Hajime Saitoh, Shuji Kozawa, Kei Miyanishi
  • Patent number: 9139894
    Abstract: 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: Grant
    Filed: July 11, 2011
    Date of Patent: September 22, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Toshiharu Aiso, Suguru Yoshida, Manabu Kubota, Kei Miyanishi, Shuji Kozawa
  • Publication number: 20140251507
    Abstract: 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: Application
    Filed: April 14, 2014
    Publication date: September 11, 2014
    Applicant: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Atsushi Mizuno, Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa
  • Patent number: 8821652
    Abstract: 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: Grant
    Filed: October 7, 2010
    Date of Patent: September 2, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Shuji Kozawa, Manabu Kubota
  • Patent number: 8802005
    Abstract: 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: Grant
    Filed: January 15, 2010
    Date of Patent: August 12, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Atsushi Mizuno, Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa
  • Patent number: 8733199
    Abstract: 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: Grant
    Filed: April 8, 2011
    Date of Patent: May 27, 2014
    Assignees: Aisin AW Co., Ltd., Nippon Steel Corporation
    Inventors: Koji Obayashi, Keita Taguchi, Susumu Kato, Shuji Kozawa, Manabu Kubota, Yuji Adachi, Hirokazu Sato
  • Patent number: 8673094
    Abstract: 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: Grant
    Filed: October 5, 2011
    Date of Patent: March 18, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa, Manabu Kubota, Tatsuro Ochi
  • Publication number: 20130340895
    Abstract: 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: Application
    Filed: August 30, 2013
    Publication date: December 26, 2013
    Applicants: SANYO SPECIAL STEEL CO., LTD., NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Shuji KOZAWA, Manabu KUBOTA, Osamu KADA, Motohiro NISHIKAWA, Takashi TANAKA, Norimasa TSUNEKAGE
  • Patent number: 8535459
    Abstract: 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: Grant
    Filed: May 17, 2011
    Date of Patent: September 17, 2013
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kei Miyanishi, Manabu Kubota, Shuji Kozawa
  • Publication number: 20130220489
    Abstract: 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: Application
    Filed: March 18, 2013
    Publication date: August 29, 2013
    Inventors: Atsushi Mizuno, Masayuki Hashimura, Hajime Saitoh, Shuji Kozawa, Kei Miyanishi
  • Patent number: 8430974
    Abstract: A steel component formed by carburizing and then induction-hardening of a steel consisting essentially of, by mass, C: minimum 0.08% and less than 0.3%; Si: maximum 2.0%; Mn: from 0.2% to 3.0%; P: maximum 0.03%; S: from 0.005% to 0.05%; Ni: maximum 1.5%; Cr: maximum 3.0%; Mo: maximum 1.0%; O: maximum 0.0025%; and N: from 0.005% to 0.03%; and further including either or both of, by mass, Al: from 0.005% to 0.05%, and Ti: from 0.005% to 0.05%; and still further including either or both of, by mass, V: maximum 0.3%, and Nb: maximum 0.3%; and a balance including Fe and unavoidable impurities. The hardness of the surface layer is at least 55 HRC and the hardness of the core portion is from 20 to 50 HRC. The core portion does not include a martensite structure.
    Type: Grant
    Filed: April 28, 2006
    Date of Patent: April 30, 2013
    Assignees: Aisin AW Co., Ltd., Nippon Steel Corporation Muroran Works
    Inventors: Takao Taniguchi, Hisao Shirai, Kouji Ohbayashi, Kazuaki Okada, Hideo Kanisawa, Shuji Kozawa
  • Publication number: 20130101457
    Abstract: 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: Application
    Filed: July 11, 2011
    Publication date: April 25, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Toshiharu Aiso, Suguru Yoshida, Manabu Kubota, Kei Miyanishi, Shuji Kozawa
  • Publication number: 20130048156
    Abstract: 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: Application
    Filed: October 5, 2011
    Publication date: February 28, 2013
    Inventors: Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa, Manabu Kubota, Tatsuro Ochi
  • Publication number: 20120318408
    Abstract: The present invention relates to a steel part securing temper softening resistance at 300° C. characterized by (a) the content of Si in the steel being made 0.7% or more, (b) the content of C in the carburized layer being made 0.9 to 1.1% for a hyper eutectic content of C by carburization, (c) the carbides with an outside diameter of 0.1 ?m or more (proeutectoid cementite or spherical carbides) not being allowed to be present after carburization, and (d) the amount of residual austenite after carburization, quenching, and tempering being made less than 30%. The gist lies in a steel part excellent in temper softening resistance which is comprised of steel containing predetermined ingredients, has a total content of Mn and Cr of 2.5% or less, and is carburized, quenched, and tempered on its surface, which has a content of C at a part at a 50 ?m depth from the surface of 0.9 to 1.1%, does not contain proeutectoid cementite or spherical carbides of an average diameter of 0.
    Type: Application
    Filed: April 14, 2011
    Publication date: December 20, 2012
    Inventors: Shuji Kozawa, Manabu Kubota