Vanadium, Zirconium, Titanium Or Molybdenum Containing Patents (Class 420/93)
  • Patent number: 10351925
    Abstract: A steel plate excellent in acid dew point corrosion resistance has a composition, in mass percent, from 0.001 to 0.15% of C, 0.80% or less of Si, 1.50% or less of Mn, 0.025% or less of P, 0.030% or less of S, from 0.10 to 1.00% of Cu, 0.50% or less of Ni, from 0.05 to 0.25% of Cr, 0.01 to 0.08% of Mo, 0.100% or less of Al, from 0 to 0.20% in total of Ti, Nb, and V, from 0 to 0.010% of B, from 0 to 0.10% in total of Sb and Sn, and a balance of Fe and unavoidable impurities, having a ferrite single phase structure, or a structure containing 30% by volume or less in total of one or more of cementite, pearlite, bainite, and martensite, with the balance ferrite phase. Ferrite crystal grains have an average crystal grain diameter of 12.0 mm or less.
    Type: Grant
    Filed: March 26, 2015
    Date of Patent: July 16, 2019
    Assignee: NIPPON STEEL NISSHIN CO., LTD.
    Inventors: Yukio Katagiri, Akito Kawamoto, Susumu Fujiwara
  • Patent number: 10196704
    Abstract: There are provided a steel sheet for resistance to composite corrosion from sulfuric acid and hydrochloric acid, having excellent wear resistance and surface quality, and a method of manufacturing the same. The steel sheet having excellent surface qualities may be provided by improving resistance to erosion occurring due to coal cinders to increase a lifespan thereof and securing excellent resistance to composite corrosion from sulfuric acid and hydrochloric acid. Wear resistance may be significantly increased by adding P, and in order to solve a problem in that wear resistance is deteriorated due to the addition of P, a component system and a hot rolling process condition may be controlled, thereby forming a corrosion resistant layer having excellent corrosion resistance.
    Type: Grant
    Filed: November 25, 2013
    Date of Patent: February 5, 2019
    Assignee: POSCO
    Inventors: Jeong-Bong Yoon, Byoung-Ho Lee, Jong-Hwa Kim
  • Patent number: 9466411
    Abstract: A non-oriented electrical steel sheet has a chemical composition including, in mass %, C: 0.005% or less, Si: 5% or less, Al: 3% or less, Mn: 5% or less, S: 0.005% or less, P: 0.2% or less, N: 0.005% or less, Mo: 0.001 to 0.04%, Ti: 0.0030% or less, Nb: 0.0050% or less, V: 0.0050% or less, Zr: 0.0020% or less, one or both of Sb and Sn: 0.001 to 0.1% in total, and the balance being iron and incidental impurities.
    Type: Grant
    Filed: September 26, 2012
    Date of Patent: October 11, 2016
    Assignee: JFE Steel Corporation
    Inventors: Yoshihiko Oda, Hiroaki Toda, Tadashi Nakanishi, Yoshiaki Zaizen
  • Publication number: 20150034049
    Abstract: A rolled steel bar for hot forging consisting, by mass percent, of C: 0.25-0.50%, Si: 0.40-1.0%, Mn: 1.0-1.6%, S: 0.005-0.035%, Al: 0.005-0.050%, V: 0.10-0.30%, and N: 0.005-0.030%, and the balance of Fe and impurities, i.e., P: 0.035% or less and O: 0.0030% or less, wherein Fn1=C+Si/10+Mn/5+5Cr/22+1.65V?5S/7 is 0.90 to 1.20. The predicted maximum width of nonmetallic inclusions at the time when a cumulative distribution function obtained by extreme value statistical processing by taking the width of nonmetallic inclusion in an R1/2 part of a longitudinal cross section of the steel bar as W (mm) is 99.99% is 100 mm or narrower. The number density of sulfides each having a circle-equivalent diameter of 0.3 to 1.0 mm observed per unit area of the R1/2 part of a transverse cross section of the steel bar is 500 pieces/mm2 or higher.
    Type: Application
    Filed: February 5, 2013
    Publication date: February 5, 2015
    Inventors: Naoki Matsui, Masashi Higashida, Hitoshi Matsumoto, Yutaka Neishi, Talzo Makino, Kouji Morita, Yoshihiro Tanimura, Naoyuki Sashima, Toshimasa Itou
  • Publication number: 20140332517
    Abstract: The present disclosure relates generally to welding alloys and, more specifically, to welding consumables (e.g., welding wires and rods) for welding, such as Gas Metal Arc Welding (GMAW), Gas Tungsten Arc Welding (GTAW), Shielded Metal Arc Welding (SMAW), and Flux Core Arc Welding (FCAW). In an embodiment, a welding alloy includes less than approximately 1 wt % manganese as well as one or more strengthening agents selected from the group: nickel, cobalt, copper, carbon, molybdenum, chromium, vanadium, silicon, and boron. Additionally, the welding alloy has a carbon equivalence (CE) value that is less than approximately 0.23, according to the Ito and Bessyo carbon equivalence equation. The welding alloy also includes one or more grain control agents selected from the group: niobium, tantalum, titanium, zirconium, and boron, wherein the welding alloy includes less than approximately 0.6 wt % grain control agents.
    Type: Application
    Filed: April 30, 2014
    Publication date: November 13, 2014
    Applicant: HOBART BROTHERS COMPANY
    Inventors: Steven Edward Barhorst, Kevin M. Krieger, Joseph C. Bundy, Mario Anthony Amata, Daryl L. Duncan, Susan Renata Fiore
  • Patent number: 8878541
    Abstract: A battery voltage monitoring circuit includes a first power supply terminal to be connected to the positive terminal of a battery pack having rechargeable cells connected in series; a first supply voltage sensing terminal to be connected to the positive terminal of the battery pack; a first resistor connected between the first power supply terminal and the first supply voltage sensing terminal; a second supply voltage sensing terminal to be connected to the negative terminal of a first rechargeable cell of the rechargeable cells, the first rechargeable cell being on the positive terminal side of the battery pack and connected to the positive terminal of the battery pack; a second resistor connected between the second supply voltage sensing terminal and the first power supply terminal; and a first comparator configured to compare a voltage at the first power supply terminal and a voltage at the first supply voltage sensing terminal.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: November 4, 2014
    Assignee: Mitsumi Electric Co., Ltd.
    Inventors: Akihiro Nishizawa, Takashi Takeda
  • Publication number: 20140301888
    Abstract: This H-beam steel contains, in mass %, C, Si, Mn, Al, Ti, N, O, Nb, and B. The H-beam steel has composition in which the amount of Nb and the amount of B satisfy, in mass %, 0.070?Nb+125B?0.155, and has a metal structure in which, in a microstructure, an area fraction of bainite is not less than 70%, a total of an area fraction of pearlite and an area fraction of cementite is not more than 15%, and the remainder is at least one of ferrite and island martensite. The effective crystalline-grain size of the bainite is not more than 40 ?m, and the thickness of a flange falls in a range of 12 to 40 mm.
    Type: Application
    Filed: December 12, 2012
    Publication date: October 9, 2014
    Inventors: Kazutoshi Ichikawa, Teruyuki Wakatsuki, Noriaki Onodera, Kohichi Yamamoto
  • Publication number: 20140227126
    Abstract: The present invention provides high strength steel pipe for line pipe superior in low temperature toughness suppressed in drop of toughness of the HAZ and a method of production of the same, more particularly high strength steel plate for line pipe used as a material for high strength steel pipe for line pipe and a method of production of the same, in particular high strength steel pipe for line pipe superior in low temperature toughness characterized in that the chemical compositions of the base metal is, by mass %, C: 0.020 to 0.080%, Si: 0.01 to 0.50%, Mo: 0.01 to 0.15%, Al: 0.0005 to 0.030%, and Nb: 0.0001 to 0.030% contained in a range of C+0.25Si+0.1Mo+Al+Nb: 0.100% or less and the mixture of austenite and martensite present along prior austenite grain boundaries of the reheated part of the heat affected zone has a width of 10 ?m or less and a length of 50 ?m or less.
    Type: Application
    Filed: April 15, 2014
    Publication date: August 14, 2014
    Applicant: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Takuya Hara, Hitoshi Asahi, Yoshio Terada
  • Patent number: 8778096
    Abstract: Provided is a low yield ratio, high strength and high toughness steel plate having excellent strain ageing resistance equivalent to API 5L X70 Grade or lower and a method for manufacturing the same. The steel plate has a metallographic microstructure that is a three-phase microstructure including bainite, M-A constituent, and quasi-polygonal ferrite, the area fraction of the bainite being 5% to 70%, the area fraction of the M-A constituent being 3% to 20%, the remainder being the quasi-polygonal ferrite, the equivalent circle diameter of the M-A constituent being 3.0 ?m or less. The steel plate has a yield ratio of 85% or less and a Charpy impact test absorbed energy of 200 J or more at ?30° C. before or after being subjected to strain ageing treatment at a temperature of 250° C. or lower for 30 minutes or less.
    Type: Grant
    Filed: September 28, 2010
    Date of Patent: July 15, 2014
    Assignee: JFE Steel Corporation
    Inventors: Junji Shimamura, Nobuyuki Ishikawa, Nobuo Shikanai
  • Patent number: 8758893
    Abstract: The present invention provides enamelware and a glaze improving the bondability between the steel substrate and enamel layer and superior in resistance to dew point corrosion by sulfuric acid and hydrochloric acid, that is, a steel substrate of a composition containing, by mass %, Cu: 0.05 to 0.5%, Si: 0.1 to 2.0%, Mn: 0.05 to 2.0%, P: 0.005 to 0.10%, and S: 0.005 to 0.1%, restricting C to C: 0.20% or less, and comprising a balance of Fe and unavoidable impurities on the surface of which an enamel layer of a thickness of 50 to 700 ?m is provided. At that time, the content of Co oxides in the enamel layer is made, converted to Co, 0.01 to 10% and/or the content of Ni oxides is made, converted to Ni, 0.05 to 20% or the total content of Ni in the steel substrate and enamel layer is made 0.005 to 4.5% with respect to the total mass of the enamelware and/or the total content of Co is made 0.008 to 4.0% with respect to the total mass of the enamelware.
    Type: Grant
    Filed: January 12, 2007
    Date of Patent: June 24, 2014
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Satoshi Nishimura, Shunji Sakamoto, Hidekuni Murakami
  • Publication number: 20140161659
    Abstract: This high-strength hot-rolled steel plate contains specific amounts of C, Si, Mn, Al, V and also Ti and/or Nb so as to fulfill C?12(V/51+Ti/48+Nb/93)>0.03, and the rest consists of iron and unavoidable impurities. Ferrite is the main microstructure, the remaining microstructure is one or more selected from the group consisting of bainite, martensite and retained austenite, wherein the average particle diameter of precipitated carbides (the total content of V, Ti and Nb is 0.02% or greater) in the ferrite is less than 6 nm.
    Type: Application
    Filed: August 15, 2012
    Publication date: June 12, 2014
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Toshio Murakami, Masao Kinefuchi, Hideo Hata
  • Patent number: 8657969
    Abstract: A high strength galvanized steel sheet has a TS of 590 MPa or more and excellent processability. The component composition contains, by mass %, C: 0.05% to 0.3%, Si: 0.7% to 2.7%, Mn: 0.5% to 2.8%, P: 0.1% or lower, S: 0.01% or lower, Al: 0.1% or lower, and N: 0.008% or lower, and the balance: Fe or inevitable impurities. The microstructure contains, in terms of area ratio, ferrite phases: 30% to 90%, bainite phases: 3% to 30%, and martensite phases: 5% to 40%, in which, among the martensite phases, martensite phases having an aspect ratio of 3 or more are present in a proportion of 30% or more.
    Type: Grant
    Filed: February 5, 2009
    Date of Patent: February 25, 2014
    Assignee: JFE Steel Corporation
    Inventors: Yoshiyasu Kawasaki, Tatsuya Nakagaito, Shinjiro Kaneko, Saiji Matsuoka
  • Publication number: 20140044585
    Abstract: There is provided a hot press-formed product, including a thin steel sheet formed by a hot press-forming method, and having a metallic structure that contains retained austenite at 3% to 20% by volume, whereby balance between strength and elongation can be controlled in a proper range and high ductility can be achieved.
    Type: Application
    Filed: April 27, 2012
    Publication date: February 13, 2014
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Junya Naitou, Toshio Murakami, Shushi Ikeda, Keisuke Okita
  • Publication number: 20140030135
    Abstract: A high-strength non-oriented electrical steel sheet contains: in mass %, C: 0.010% or less; Si: not less than 2.0% nor more than 4.0%; Mn: not less than 0.05% nor more than 0.50%; Al: not less than 0.2% nor more than 3.0%; N: 0.005% or less; S: not less than 0.005% nor more than 0.030%; and Cu: not less than 0.5% nor more than 3.0%, a balance being composed of Fe and inevitable impurities. An expression (1) is established where a Mn content is represented as [Mn] and a S content is represented as [S], and not less than 1.0×104 pieces nor more than 1.0×106 pieces of sulfide having a circle-equivalent diameter of not less than 0.1 ?m nor more than 1.0 ?m are contained per 1 mm2.
    Type: Application
    Filed: April 11, 2012
    Publication date: January 30, 2014
    Applicant: Nippon Steel Corporation
    Inventors: Yoshihiro Arita, Masahiro Fujikura, Hidekuni Murakami
  • Publication number: 20130315777
    Abstract: Disclosed is a weld metal which is formed by gas-shielded arc welding using a flux-cored wire, and which has a specific chemical composition, in which retained austenite particles are present in a number density of 2500 per square millimeter or more and in a total volume fraction of 4.0% or more based on the total volume of entire structures of the weld metal. The weld metal has excellent hydrogen embrittlement resistance and is resistant to cracking at low temperatures even when the weld metal has a high strength.
    Type: Application
    Filed: February 1, 2012
    Publication date: November 28, 2013
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hidenori Nako, Takuya Kochi, Wataru Urushihara, Munenobu Sato, Yoshihiko Kitagawa
  • Patent number: 8529829
    Abstract: Disclosed herein is a high-strength hot-rolled steel sheet which is characterized by high strength (in terms of tensile strength at 900 MPa level) and excellent combined formability expressed by balance between strength and ductility [tensile strength (TS)×total elongation (El)] and balance between strength and stretch flangeability [tensile strength (TS)×bore expanding ratio (?)]. The hot-rolled steel sheet contains C: no less than 0.02% and no more than 0.15%, Si: no less than 0.2% and no more than 2.0%, Mn: no less than 0.5% and no more than 2.5%, Al: no less than 0.02% and no more than 0.15%, Cu: no less than 1.0% and no more than 3.0%, Ni: no less than 0.5% and no more than 3.0%, and Ti: no less than 0.03% and no more than 0.5%. (% means mass %) It also has a metallographic structure in longitudinal cross section such that the sum of bainitic ferrite and granular bainitic ferrite accounts for no less than 85% by area.
    Type: Grant
    Filed: March 14, 2007
    Date of Patent: September 10, 2013
    Assignee: Kobe Steel, Ltd.
    Inventors: Motoo Satou, Tetsuo Soshiroda
  • Publication number: 20130189536
    Abstract: A steel for electron-beam welding according to the present invention includes at least C: 0.02% to 0.10%, Si: 0.03% to 0.30%, Mn: 1.5% to 2.5%, Ti: 0.005% to 0.015%, N: 0.0020% to 0.0060%, and O: 0.0010% to 0.0035%, further includes S: limited to 0.010% or less, P: limited to 0.015% or less, and Al: limited to 0.004% or less, with a balance including iron and inevitable impurities. An index value CeEBB obtained by substituting composition of the steel into following Formula 1 falls in the range of 0.42 to 0.65%, the number of oxide having an equivalent circle diameter of 1.0 ?m or more is 20 pieces/mm2 or less at a thickness center portion in cross section along the thickness direction of the steel, and the number of oxide containing Ti of 10% or more and having an equivalent circle diameter of not less than 0.05 ?m or more and less than 0.5 ?m falls in the range of 1×103 to 1×105 pieces/mm2 at the thickness center portion.
    Type: Application
    Filed: October 27, 2011
    Publication date: July 25, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Ryuichi Honma, Ryuji Uemori, Tadashi Ishikawa, Akihiko Kojima, Manabu Hoshino
  • Publication number: 20130136950
    Abstract: A multi-phase steel sheet having microstructure having in combination ferrite, martensite of between 3% and 65% by volume, and at least one microstructure selected from the group consisting of, bainite and retained austenite, and having fine complex precipitates selected from the group of TiC, NbC, TiN, NbN, (Ti.Nb)C, (Ti.Nb)N, and (Ti.Nb)(C.N) particles having at least 50% smaller than 20 nm in size, and physical properties having tensile strength greater than about 780 megapascals and at least one of the properties of elongation greater than about 10%, yield ratio greater than about 70%, and hole expansion ratio greater than about 50%.
    Type: Application
    Filed: January 30, 2013
    Publication date: May 30, 2013
    Applicant: NUCOR CORPORATION
    Inventor: Weiping SUN
  • Patent number: 8449845
    Abstract: In light of the recent analytical technology demanded of fast and accurate measurement of high purity materials, a zirconium crucible is provided for melting an analytical sample and is capable of inhibiting the inclusion of impurities from the crucible by using a high-purity crucible, improving the durability of high-purity zirconium as an expensive crucible material, and increasing the number of times that the zirconium crucible can be used. With this zirconium crucible used for melting an analytical sample in the pretreatment of the analytical sample, the purity excluding gas components is 3N or higher, and the content of carbon as a gas component is 100 mass ppm or less.
    Type: Grant
    Filed: August 8, 2008
    Date of Patent: May 28, 2013
    Assignee: JX Nippon Mining & Metals Corporation
    Inventors: Yuichiro Shindo, Masahiro Sakaguchi, Mitsuru Yamaguchi
  • 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
  • Patent number: 8361248
    Abstract: The present invention provides a high strength steel having unprecedentedly superior CTOD (fracture toughness) properties satisfying not only the CTOD properties of the FL zone at ?60° C., but also the CTOD properties of the ICHAZ zone in small and medium heat input multilayer welding, etc.; and a method of production of the same. The steel of the present invention is steel superior in CTOD properties of the heat-affected zone containing, by mass %, C: 0.015 to 0.045%, Si: 0.05 to 0.2%, Mn: 1.5 to 2.0%, Cu: 0.25 to 0.5%, Ni: 0.7 to 1.5%, P: 0.008% or less, S: 0.005% or less, Al: 0.004% or less, Ti: 0.005 to 0.015%, Nb: 0.005% or less, O: 0.0015 to 0.0035%, and N: 0.002 to 0.006%, PCTOD: 0.065 or less, CeqH: 0.235 or less and the balance consisting of Fe and unavoidable impurities.
    Type: Grant
    Filed: December 4, 2008
    Date of Patent: January 29, 2013
    Assignee: Nippon Steel Corporation
    Inventors: Rikio Chijiiwa, Ryuji Uemori, Yoshiyuki Watanabe, Kazuhiro Fukunaga, Akihiko Kojima, Yoshihide Nagai
  • Patent number: 8337642
    Abstract: The present invention provides a spring steel that has superior hardenability, undergoes less pitting in a corrosive environment, and can achieve higher stress and toughness. More specifically, the present invention provides a high-strength and high-toughness spring steel with improved hardenability and pitting resistance, containing, in mass percent, 0.40 to 0.70% carbon, 0.05 to 0.50% silicon, 0.60 to 1.00% manganese, 1.00 to 2.00% chromium, 0.010 to 0.050% niobium, 0.005 to 0.050% aluminum, 0.0045 to 0.0100% nitrogen, 0.005 to 0.050% titanium, 0.0005 to 0.0060% boron, no more than 0.015% phosphorus and no more than 0.010% sulfur, the remainder being composed of iron and unavoidable impurities, the steel having a tensile strength of at least 1700 MPa in 400° C. tempering after quenching and a Charpy impact value of at least 40 J/cm2 for a 2 mm U-notched test piece of JIS Z 2202 and the parameter Fce being at least 1.70.
    Type: Grant
    Filed: April 26, 2012
    Date of Patent: December 25, 2012
    Assignee: Mitsubishi Steel Mfg. Co., Ltd.
    Inventors: Tatsuo Fukuzumi, Hidenori Hiromatsu, Motoyuki Sato, Ryo Hara
  • Patent number: 8293379
    Abstract: The quenchable steel sheet has an alloy composition including carbon (C) in an amount of 0.15˜0.30 wt %, silicon (Si) in an amount of 0.05˜0.5 wt %, manganese (Mn) in an amount of 1.0˜2.0 wt %, boron (B) in an amount of 0.0005˜0.0040 wt %, sulfur (S) in an amount of 0.003 wt % or less, phosphorus (P) in an amount of 0.012 wt % or less, one or more selected from among calcium (Ca) in an amount of 0.0010˜0.0040 wt % and copper (Cu) in an amount of 0.05˜1.0 wt %, two or more selected from among cobalt (Co), zirconium (Zr) and antimony (Sb), and iron (Fe). Alloy elements are controlled to increasing hot ductility and enabling pressing at 600˜900° C. so that a tensile strength of 1400 MPa or more and an elongation of 8% or more are obtained after pressing.
    Type: Grant
    Filed: February 17, 2011
    Date of Patent: October 23, 2012
    Assignee: Hyundai Steel Company
    Inventors: Taekjoon Kim, Seungha Lee, Seongju Kim
  • Patent number: 8197614
    Abstract: The present invention provides a spring steel that has superior hardenability, undergoes less pitting in a corrosive environment, and can achieve higher stress and toughness. More specifically, the present invention provides a high-strength and high-toughness spring steel with improved hardenability and pitting resistance, containing, in mass percent, 0.40 to 0.70% carbon, 0.05 to 0.50% silicon, 0.60 to 1.00% manganese, 1.00 to 2.00% chromium, 0.010 to 0.050% niobium, 0.005 to 0.050% aluminum, 0.0045 to 0.0100% nitrogen, 0.005 to 0.050% titanium, 0.0005 to 0.0060% boron, no more than 0.015% phosphorus and no more than 0.010% sulfur, the remainder being composed of iron and unavoidable impurities, the steel having a tensile strength of at least 1700 MPa in 400° C. tempering after quenching and a Charpy impact value of at least 40 J/cm2 for a 2 mm U-notched test piece of JIS Z 2202 and the parameter Fce being at least 1.70.
    Type: Grant
    Filed: October 26, 2010
    Date of Patent: June 12, 2012
    Assignee: Mitsubishi Steel Mfg. Co., Ltd.
    Inventors: Tatsuo Fukuzumi, Hidenori Hiromatsu, Motoyuki Sato, Ryo Hara
  • Publication number: 20120063945
    Abstract: Provided is a steel for machine structural use which has excellent machinability (particularly, with respect to tool life) for both intermittent cutting with a high-speed steel tool and continuous cutting with a cemented carbide tool while maintaining strength properties required of the steel for machine structural use. Specifically, the steel for machine structural use contains C: 0.05-0.9 mass %, Si: 0.03-2 mass %, Mn: 0.2-1.8 mass %, P: 0.03 mass % or less, S: 0.03 mass % or less, Al: 0.1-0.5 mass %, N: 0.002-0.017 mass %, and O: 0.003 mass % or less, and contains one or more selected from a group consisting of Ti: 0.05 mass % or less (excluding 0 mass %) and B: 0.008 mass % or less (excluding 0 mass %), with the remainder being iron and unavoidable impurities, and satisfies all of the following inequalities (1)-(3) below: (1): [N]?0.3[Ti]?1.4[B]<(0.0004/[Al])?0.002; (2): [Ti]?[N]/0.3<0.005; and (3): [B]?([N]?0.3[Ti])/1.4<0.003 when [Ti]?[N]/0.3<0 and [B]<0.003 when [Ti]?[N]/0.3?0.
    Type: Application
    Filed: June 1, 2010
    Publication date: March 15, 2012
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd.)
    Inventors: Takehiro Tsuchida, Tomokazu Masuda, Masaki Shimamoto, Mutsuhisa Nagahama
  • Publication number: 20120048427
    Abstract: Steel for nitrocarburizing includes, by mass %, C: 0% to less than 0.15%; Si: 0.01% to 1.00%; Mn: 0.01% to 1.00%; S: 0.0001% to 0.050%; Al: 0.0001% to 0.050%; Ti: more than 0.50% to 1.50%; N: 0.0005% to 0.0100%; and the balance consisting of Fe and inevitable impurities, in which P is limited to 0.050% or less; O is limited to 0.0060% or less; and the amount of Ti [Ti %], the amount of C [C %], the amount of N [N %], and the amount of S [S %] satisfy 0.48<[Ti %]?47.9×([C %]/12+[N %]/14+[S %]/32)?1.20.
    Type: Application
    Filed: January 25, 2011
    Publication date: March 1, 2012
    Inventor: Manabu Kubota
  • Publication number: 20120014828
    Abstract: In a non-oriented electrical steel sheet, Si: not less than 1.0 mass % nor more than 3.5 mass %, Al: not less than 0.1 mass % nor more than 3.0 mass %, Ti: not less than 0.001 mass % nor more than 0.01 mass %, Bi: not less than 0.001 mass % nor more than 0.01 mass %, and so on are contained. (1) expression described below is satisfied when a Ti content (mass %) is represented as [Ti] and a Bi content (mass %) is represented as [Bi]. [Ti]?0.8×[Bi]+0.
    Type: Application
    Filed: May 25, 2010
    Publication date: January 19, 2012
    Applicant: NIPPON STEEL CORPORATION
    Inventors: Masafumi Miyazaki, Hideaki Yamamura, Takeshi Kubota, Yousuke Kurosaki, Kazuto Kawakami, Kazumi Mizukami, Takeaki Wakisaki
  • Publication number: 20110318214
    Abstract: A water atomised prealloyed chromium-free, iron-based steel powder is provided which comprises by weight-%: 0.05-0.4 V, 0.09-0.3 Mn, less than 0.1 Cr, less than 0.1 Mo, less than 0.1 Ni, less than 0.2 Cu, less than 0.1 C, less than 0.25 O, and less than 0.5 of unavoidable impurities, with the balance being iron.
    Type: Application
    Filed: March 15, 2010
    Publication date: December 29, 2011
    Applicant: HOGANAS AB (PUBL)
    Inventor: Sven Bengtsson
  • Patent number: 8052809
    Abstract: Disclosed are amorphous, ductile brazing foils with a composition consisting essentially of FeRestNiaCrbSicBdPe, wherein 0 atomic %?a<25 atomic %; 0 atomic %?b?15 atomic %; 1 atomic %?c?10 atomic %; 4 atomic %?d?15 atomic %; 1 atomic %?e?9 atomic %; any impurities?0.5 atomic %; rest Fe, wherein 2 atomic %?c+e?10 atomic % and 15 atomic %?c+d+e?22 atomic %, or consisting essentially of FeRestNiaCrbMofCugSicBdPe, wherein 0 atomic %?a<25 atomic %; 0 atomic %?b?15 atomic %; 1 atomic %<c?10 atomic %; 4 atomic %?d?15 atomic %; 1 atomic %?e?9 atomic %; 0 atomic %<f?3 atomic %; 0 atomic %?g?3 atomic %; any impurities?0.5 atomic %; rest Fe, wherein 2 atomic %?c+e?10 atomic % and 15 atomic %?c+d+e?22 atomic %. Also disclosed are brazed objects formed using these foils, particularly exhaust gas recirculation coolers and oil coolers, and methods for making the brazing foils and for making the brazed parts.
    Type: Grant
    Filed: June 3, 2008
    Date of Patent: November 8, 2011
    Assignee: Vacuumschmelze GmbH & Co. KG
    Inventors: Thomas Hartmann, Dieter Nuetzel
  • Publication number: 20110268600
    Abstract: The invention provides a steel material with satisfactory hydrogen embrittlement resistance, and particularly it relates to high-strength steel with satisfactory hydrogen embrittlement resistance and a strength of 1200 MPa or greater, as well as a process for production thereof. At least one simple or compound deposit of oxides, carbides or nitrides as hydrogen trap sites which trap hydrogen with a specific trap energy is added to steel, where the mean sizes, number densities, and length-to-thickness ratios (aspect ratio) are in specific ranges. By applying the specific steel components and production process it is possible to obtain high-strength steel with excellent hydrogen embrittlement resistance.
    Type: Application
    Filed: July 15, 2011
    Publication date: November 3, 2011
    Applicant: Nippon Steel Corporation
    Inventors: Shingo YAMASAKI, Daisuke Hirakami, Toshimi Tarui, Seiki Nishida
  • Publication number: 20110236696
    Abstract: A high mechanical strength reinforcement steel comprising, in addition to iron, at most about 0.5% by weight carbon, at most about 0.5% by weight vanadium and/or niobium, and the usual residual elements of scrap steel. A method of reinforcing a dwelling from damage resulting from seismic activity, the method comprising providing, as a component of the dwelling, at least one rebar of a composition comprising, in addition to iron, at most about 0.5% by weight carbon, at most about 0.5% by weight vanadium and/or niobium, at most 1.7% by weight of manganese, at most 0.5% by weight of silicon, and the usual residual elements of scrap steel.
    Type: Application
    Filed: March 25, 2010
    Publication date: September 29, 2011
    Inventors: Winky Lai, Cameron A. Cossette, James F. Petersen
  • Publication number: 20110159314
    Abstract: The quenchable steel sheet has an alloy composition including carbon (C) in an amount of 0.15˜0.30 wt %, silicon (Si) in an amount of 0.05˜0.5 wt %, manganese (Mn) in an amount of 1.0˜2.0 wt %, boron (B) in an amount of 0.0005˜0.0040 wt %, sulfur (S) in an amount of 0.003 wt % or less, phosphorus (P) in an amount of 0.012 wt % or less, one or more selected from among calcium (Ca) in an amount of 0.0010˜0.0040 wt % and copper (Cu) in an amount of 0.05˜1.0 wt %, two or more selected from among cobalt (Co), zirconium (Zr) and antimony (Sb), and iron (Fe). Alloy elements are controlled to increasing hot ductility and enabling pressing at 600˜900° C. so that a tensile strength of 1400 MPa or more and an elongation of 8% or more are obtained after pressing.
    Type: Application
    Filed: February 17, 2011
    Publication date: June 30, 2011
    Applicant: HYUNDAI STEEL COMPANY
    Inventors: Taekjoon KIM, Seungha LEE, Seongju KIM
  • Patent number: 7922838
    Abstract: The present invention provides: a steel for a welded structure to be used for a crude oil tank that exhibits excellent general and local corrosion resistance in crude oil corrosion caused in a steel oil tank and is capable of suppressing the formation of corrosion products (sludge) containing solid sulfur; a method for producing said steel; a crude oil tank; and a method for preventing a crude oil tank against corrosion. The present invention makes it possible to obtain general and local corrosion resistance in a crude oil tank environment and suppress the formation of corrosion products (sludge) containing solid sulfur by using a steel: containing, in mass, 0.001 to 0.2% C, 0.01 to 2.5% Si, 0.1 to 2% Mn, 0.03% or less P, 0.007% or less S, 0.01 to 1.5% Cu, 0.001 to 0.3% Al, 0.001 to 0.01% N as basic components and, further, 0.01 to 0.2% Mo and/or 0.01 to 0.5% W; and preferably satisfying the following expression; Solute Mo+Solute W?0.005%.
    Type: Grant
    Filed: June 18, 2003
    Date of Patent: April 12, 2011
    Assignee: Nippon Steel Corporation
    Inventors: Akira Usami, Kenji Katoh, Toshiei Hasegawa, Akira Shishibori
  • Patent number: 7910512
    Abstract: To provide a production process of an electrode catalyst for fuel cell whose initial voltage is high and whose endurance characteristics, especially, whose voltage drop being caused by high-potential application is less. A production process according to the present invention of an electrode catalyst for fuel cell is characterized in that: it includes: a dispersing step of dispersing a conductive support in a solution; a loading step of dropping a platinum-salt solution, a base-metal-salt solution and an iridium-salt solution to the resulting dispersion liquid, thereby loading respective metallic salts on the conductive support as hydroxides under an alkaline condition; and an alloying step of heating the conductive support with metallic hydroxides loaded in a reducing atmosphere to reduce them, thereby alloying them.
    Type: Grant
    Filed: September 26, 2008
    Date of Patent: March 22, 2011
    Assignee: Cataler Corporation
    Inventors: Hiroaki Takahashi, Sozaburo Ohashi, Tetsuo Kawamura, Yousuke Horiuchi, Toshiharu Tabata, Tomoaki Terada, Takahiro Nagata, Susumu Enomoto
  • Publication number: 20100330387
    Abstract: The present invention provides a high strength thick steel material excellent in toughness and weldability reduced in amount of C and amount of N, containing suitable amounts of Si, Mn, Nb, Ti, B, and O, having contents of C and Nb satisfying C—Nb/7.74?0.004, having a density of Ti-containing oxides of a particle size of 0.05 to 10 ?m of 30 to 300/mm2, and having a density of Ti-containing oxides of a particle size over 10 ?m of 10/mm2 or less, produced by treating steel by preliminary deoxidation to adjust the dissolved oxygen to 0.005 to 0.015 mass %, then adding Ti and, furthermore, vacuum degassing the steel for 30 minutes or more, smelting it, then continuously casting it to produce a steel slab or billet, heating the steel slab or billet to 1100 to 1350° C., hot rolling the slab or billet to a thickness of 40 to 150 mm, then cooling it.
    Type: Application
    Filed: September 26, 2008
    Publication date: December 30, 2010
    Inventors: Suguru Yoshida, Hiroshi Kita, Teruhisa Okumura, Hirokazu Sugiyama, Teruyuki Wakatsuki
  • Patent number: 7850794
    Abstract: The present invention provides a spring steel that has superior hardenability, undergoes less pitting in a corrosive environment, and can achieve higher stress and toughness. More specifically, the present invention provides a high-strength and high-toughness spring steel with improved hardenability and pitting resistance, containing, in mass percent, 0.40 to 0.70% carbon, 0.05 to 0.50% silicon, 0.60 to 1.00% manganese, 1.00 to 2.00% chromium, 0.010 to 0.050% niobium, 0.005 to 0.050% aluminum, 0.0045 to 0.0100% nitrogen, 0.005 to 0.050% titanium, 0.0005 to 0.0060% boron, no more than 0.015% phosphorus and no more than 0.010% sulfur, the remainder being composed of iron and unavoidable impurities, the steel having a tensile strength of at least 1700 MPa in 400° C. tempering after quenching and a Charpy impact value of at least 40 J/cm2 for a 2 mm U-notched test piece of JIS 2202 and the parameter Fce being at least 1.70.
    Type: Grant
    Filed: November 13, 2003
    Date of Patent: December 14, 2010
    Assignee: Mitsubishi Steel Mfg. Co., Ltd.
    Inventors: Tatsuo Fukuzumi, Hidenori Hiromatsu, Motoyuki Sato, Ryo Hara
  • Publication number: 20100247368
    Abstract: A bainitic steel alloy and a method for making such an alloy are disclosed, in which the bainite plates are particularly small, less than 50 nanometres in width. In preferred embodiments of the invention, each bainite plate is surrounded by a film of retained austenite; the level of retained austenite in the alloy is greater than 10%; and the alloy is substantially free of blocky unstable austenite and cementite.
    Type: Application
    Filed: March 10, 2010
    Publication date: September 30, 2010
    Applicant: ROLLS-ROYCE PLC
    Inventors: Martin J. RAWSON, Mathew J. PEET, Harshad K.D.H BHADESHIA, Scott D. WOOD, Paul O. HILL, Emma E. BOOTH
  • Publication number: 20100098576
    Abstract: An iron-based soft magnetic alloy which is for use in various transformers, various choke coils, noise suppression measures, power supply parts, laser power supplies, pulsed-power magnetic parts for accelerators, various motors, various generators, magnetic shields, antennas, sensors, etc.; a thin ribbon of an amorphous alloy for producing the magnetic alloy; and a magnetic part comprising the magnetic alloy. The magnetic alloy comprises, in terms of at. %, copper in an amount (x) satisfying 0.1?x?3, boron in an amount (y) satisfying 10?y?20, and iron and impurities as the remainder. It contains, in terms of mass %, the following impurities: up to 0.01% aluminum, 0.001-0.05% sulfur, 0.01-0.5% manganese, 0.001-0.1% nitrogen, and up to 0.1% oxygen. The magnetic alloy has a structure at least part of which comprises a crystal phase having a crystal grain diameter of 60 nm or smaller (excluding 0).
    Type: Application
    Filed: March 12, 2008
    Publication date: April 22, 2010
    Applicant: Hitachi Metals, Ltd.
    Inventors: Yoshihito Yoshizawa, Motoki Ohta
  • Publication number: 20100084057
    Abstract: A high strength cold-rolled steel sheet and a high strength plated steel sheet which have an excellent surface appearance required for outer panels of automobiles and which have an extremely high r value in a direction at 45° with respect to the rolling direction and which have excellent press formability and a tensile strength of at least 340 MPa and a process for their manufacture are provided. The steel sheets have a chemical composition consisting essentially of, in mass %, C: 0.0005-0.025%, Si: at most 0.2%, Mn: 0.3-2.5%, P: at most 0.15%, S: at most 0.02%, N: at most 0.006%, sol. Al: less than 0.005%, Ti: 0.005-0.05%, and Nb: 0.020-0.200% with the mass ratio (Nb/Ti) of the contents of Nb and Ti being at least 2, and a remainder of Fe and impurities, and they have an r value in a direction at 45° with respect to the rolling direction (r45) of at least 1.80 and/or a mean r value (0 of at least 1.60, and a tensile strength of at least 340 MPa.
    Type: Application
    Filed: September 4, 2009
    Publication date: April 8, 2010
    Inventors: Seiji Furuhashi, Jun Haga, Takayuki Nishi
  • Publication number: 20100078097
    Abstract: A steel material superior in high temperature characteristics and toughness is provided, that is, a steel material containing, by mass %, C: 0.005% to 0.03%, Si: 0.05% to 0.40%, Mn: 0.40% to 1.70%, Nb: 0.02% to 0.25%, Ti: 0.005% to 0.025%, N: 0.0008% to 0.0045%, B: 0.0003% to 0.0030%, restricting P: 0.030% or less, S: 0.020% or less, Al: 0.03% or less, and having a balance of Fe and unavoidable impurities, where the contents of C and Nb satisfy C?Nb/7.74?0.02 and Ti-based oxides of a grain size of 0.05 to 10 ?m are present in a density of 30 to 300/mm2.
    Type: Application
    Filed: April 4, 2008
    Publication date: April 1, 2010
    Inventors: Suguru Yoshida, Hiroshi Kita, Teruhisa Okumura, Hirokazu Sugiyama, Teruyuki Wakatsuki
  • Publication number: 20090274573
    Abstract: The invention provides a machine structural steel excellent in machinability and strength properties that has good machinability over a broad range of machining speeds and also has high impact properties and high yield ratio, which machine structural steel comprises, in mass %, C: 0.1 to 0.85%, Si: 0.01 to 1.5%, Mn: 0.05 to 2.0%, P: 0.005 to 0.2%, S: 0.001 to 0.15%, total Al: greater than 0.05% and not greater than 0.3%, Sb: less than 0.0150% (including 0%), and total N: 0.0035 to 0.020%, solute N being limited to 0.0020% or less, and a balance of Fe and unavoidable impurities.
    Type: Application
    Filed: December 25, 2007
    Publication date: November 5, 2009
    Inventors: Kei Miyanishi, Masayuki Hashimura, Atsushi Mizuno, Kenichiro Miyamoto
  • Patent number: 7588609
    Abstract: The claimed invention involves a novel composition of matter comprising a mixture of Fe—Mo Intermetallic and copper oxide. A novel composition of matter of Fe—Mo Intermetallic, copper oxide and calcium carbonate is also claimed. The claimed invention also involves a novel friction lining additive comprising Fe—Mo Intermetallic and copper oxide for improved braking effectiveness. Fe—Mo Intermetallic, copper oxide and calcium carbonate may also be used as a friction lining additive according to the present invention. The claimed invention also includes a novel motor brush comprising Fe—Mo Intermetallic and copper oxide for improved wear. Fe—Mo Intermetallic, copper oxide and calcium carbonate may also be used as a motor brush additive according to the present invention.
    Type: Grant
    Filed: July 30, 2004
    Date of Patent: September 15, 2009
    Assignee: Climax Engineered Materials, LLC
    Inventors: Mohamed H. Khan, Sunil Chandra Jha
  • Publication number: 20090098408
    Abstract: A multi-phase steel sheet having microstructure having in combination ferrite, martensite of between 3% and 65% by volume, and at least one microstructure selected from the group consisting of, bainite and retained austenite, and having fine complex precipitates selected from the group of TiC, NbC, TiN, NbN, (Ti.Nb)C, (Ti.Nb)N, and (Ti.Nb)(C.N) particles having at least 50% smaller than 20 nm in size, and physical properties having tensile strength greater than about 780 megapascals and at least one of the properties of elongation greater than about 10%, yield ratio greater than about 70%, and hole expansion ratio greater than about 50%.
    Type: Application
    Filed: October 6, 2008
    Publication date: April 16, 2009
    Applicant: NUCOR CORPORATION
    Inventor: Weiping SUN
  • Publication number: 20090087335
    Abstract: The present invention provides first resistant steel superior in fire resistance having less variation in material quality and exhibiting a yield strength of ? or more of that at ordinary temperature even at 600° C. and a method of production of the same, that is, fire resistant steel characterized by containing, by mass %, C: 0.01 to 0.03%, Mn: 0.2 to 1.7%, Si: 0.5% or less, Cu: 0.7 to 2%, Mo: 0.8% or less, Nb: 0.01 to 0.3%, Ti: 0.005 to 0.03%, N: 0.006% or less, B: 0.0003 to 0.003%, V: 0.2% or less, Cr: 1% or less, Al: 0.1% or less, P: 0.03% or less, and S: 0.02% or less, containing Ni by mass ratio of Ni/Cu of 0.6 to 0.9, and comprising a balance of Fe and unavoidable impurities, and having a yield strength at 600° C. of 60% of the yield strength at 21° C.
    Type: Application
    Filed: April 28, 2006
    Publication date: April 2, 2009
    Inventors: Teruhisa Okumura, Kohichi Yamamoto, Suguru Yoshida, Hiroshi Kita, Hirokazu Sugiyama
  • Publication number: 20080247902
    Abstract: The invention relates to a high-strength, lightweight austenitic-martensitic steel and the use thereof. The inventive lightweight steel is characterized by a chrome content of more than 0.5% and less than 18%, a silicon content of more than 1% and less than 4%, a manganese content of more than 2.5% and less than 30% and an aluminum content of more than 0.05 to 4% and lies within an alloy range that is determined by the coordinates of four points (Crequ=2; Niequ=2), (Crequ=2; Niequ=24), (Crequ=20; Niequ=10) and (Crequ=20; Niequ=6.5), whereby the chrome and nickel equivalent is calculated from the chemical composition of the steel using the relations (1) and (2): Crequ=% Crequ+% Mo+1.5% Si+0.5% W+0.9% Nb+4% Al+4% Ti+1.5% Nieqe=% Ni+30% C+18% N+0.5% Mn+0.3% Co+0.2% Cu?0.2% AI (2). The indications are in weight percent and remainder substantially consists of iron and other elements usually present in steel (P. S).
    Type: Application
    Filed: June 28, 2006
    Publication date: October 9, 2008
    Inventors: Piotr R. Scheller, Andreas Weiss, Heiner Gutte
  • Publication number: 20080166256
    Abstract: The present invention provides a steel material able to secure a superior corrosion resistance in a sulfuric acid dew point corrosive environment of exhaust gas obtained by burning high S-containing fuel, containing, by mass %, C: ?0.010%, Si: ?0.10%, Cu: 0.05 to 1.00%, P: ?0.030%, S: ?0.050%, and Al: ?0.10% and comprising a balance of Fe and unavoidable impurities. Further, this steel contains one type or two types or more of Sb, Sn, Cr, Mn, Mo, Ni, Nb, V, Ti, and B.
    Type: Application
    Filed: February 24, 2006
    Publication date: July 10, 2008
    Inventors: Shunji Sakamoto, Satoshi Nishimura, Akira Usami
  • Patent number: 6824672
    Abstract: An austenitic stainless steel with a composition comprising: at most 0.15% of C; 2% to 10% of Mn; at most 2% of Ni; at most 4% of Cu; 0.1% to 0.4% of N; 10% to 20% of Cr; at most 1% of Si; at most 3% of Mo; and at most 0.7% of Ti; is used to manufacture equipment, for example furnaces, reactors or ducts, or elements of this equipment, or to coat the internal walls of this equipment, said equipment being used to implement petrochemical processes conducted at temperatures of 350° C. to 1100° C. and in which coke can be formed.
    Type: Grant
    Filed: January 15, 2002
    Date of Patent: November 30, 2004
    Assignees: Institute Francais du Petrole, USINOR
    Inventors: Philippe Lecour, Xavier Longaygue, François Ropital, Laurent Antoni
  • Publication number: 20030136483
    Abstract: A steel plate for paint use which contains C (0.12% or less), Si (1.0% or less), Mn (2.5% or less), P (0.05% or less), S (0.02% or less), and Cr (0.05% or less), Cu (0.05-3.0%), Ni (0.05-6.0%), Ti (0.025-0.15%), and Cu+Ni (0.50% or more), with Pa being 0.23% or less, in terms of mass %. Said steel plate may contain at least one additional component selected from B (0.0005-0.0030%), Al (0.05-0.50%), Ca (0.0001-0.05%), Ce (0.0001-0.05%), La (0.0001-0.05%), Nb (0.002-0.05%), V (0.01-0.10%), Zr (0.002-0.05%), and Mo (0.05-0.5$), in terms of mass %.
    Type: Application
    Filed: October 8, 2002
    Publication date: July 24, 2003
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO
    Inventors: Toshiaki Kan, Shigeo Okano, Satoru Takeshita, Masahiko Sakai
  • Patent number: 6558483
    Abstract: The Cu precipitation strengthened steel of the invention comprises, on the mass percent basis, C: 0.02-0.10%, Mn: 0.3-2.5%, Cu: 0.50-2.0%, Ni: 0.3-4.0% and Ti: 0.004-0.03% and further comprises Si: 0.01-0.4% and/or Al: 0.001-0.1%, with the contents of incidental impurities being P: not more than 0.025%, S: not more than 0.01%, N: not more than 0.006% and Se: not more than 0.005%, with the value of Pcm defined by the formula (1) given below being not more than 0.28. The steel material made of this Cu precipitation strengthened steel has good and stable CTOD toughness and is suited for use as a steel material for the construction of large industrial machines, ships, marine structures, line pipes, tanks, bridges and like welded structures.
    Type: Grant
    Filed: June 7, 2001
    Date of Patent: May 6, 2003
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Hirofumi Nakamura, Jun Furukawa
  • Patent number: 6322747
    Abstract: A high-strength spring steel having an Hv of at least 600 and an impact value of at least 40 J/cm2, comprising 0.40 to 0.70 wt. % carbon, 1.00 to 2.50 wt. % silicon, 0.30 to 0.90 wt. % manganese, 0.50 to 1.50 wt. % nickel, 1.00 to 2.00 wt. % chromium, 0.30 to 0.60 wt. % molybdenum, 0.25 to 0.50 wt. % copper, 0.01 to 0.50 wt. % vanadium, 0.010 to 0.050 wt. % niobium, 0.005 to 0.050 wt. % aluminum, 0.0045 to 0.0100 wt. % nitrogen, 0.005 to 0.050 wt. % titanium, and 0.0005 to 0.0060 wt. % boron, with phosphorus limited to 0.010 wt. % or less, sulfur to 0.010 wt. % or less, and OT to 0.0015 wt. % or less, and the remainder being composed of iron and unavoidable impurities. The spring steel has better hardness and toughness than those of existing spring steel.
    Type: Grant
    Filed: January 27, 2000
    Date of Patent: November 27, 2001
    Assignees: Mitsubishi Steel Muroran Inc., Mitsubishi Steel Mfg. Co., Ltd.
    Inventors: Tatsuo Fukuzumi, Hidenori Hiromatsu, Motoyuki Satoh, Ryo Hara