Nickel Containing Patents (Class 420/91)
  • Publication number: 20130330119
    Abstract: A forged steel for components for nuclear power plants meets a specific chemical composition. The grain size number of a metal structure thereof is 4.5 to 7.0 in terms of ASTM grain size number. It is preferred that the content of N is 0.0100 mass % or more when the mass ratio (Al/N) of the content of Al to the content of N is 1.93 or more, and that the content of Al is 0.022 mass % or more when the mass ratio (Al/N) of the content of Al to the content of N is less than 1.93. The forged steel for components for nuclear power plants exhibits excellent strength, toughness and hydrogen cracking resistance even after being subjected to a stress relief heat treatment subsequent to welding.
    Type: Application
    Filed: February 24, 2012
    Publication date: December 12, 2013
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hiroyuki Takaoka, Nobuyuki Fujitsuna
  • Publication number: 20130309003
    Abstract: This weld metal has excellent creep characteristics and has a given chemical composition. In the weld metal, the value A defined by equation (1) is 200 or greater, and carbide particles each having an equivalent-circle diameter of 0.40 ?m or more have an average equivalent-circle diameter less than 0.85 ?m. In the segments that connect the centers of three or more carbide particles which are present on a 6-?m straight line and which each has an equivalent-circle diameter of 0.40 ?m or more, the sum of the lengths of the portions where the segments intersect the carbide particles is 25% or more of the overall length of the segments. Value A=([V]/51+[Nb]/93)/{[V]×([Cr]/5+[Mo]/2)}×104??(1) In the equation, [V], [Nb], [Cr], and [Mo] respectively indicate the contents (mass %) of V, Nb, Cr, and Mo in the weld metal.
    Type: Application
    Filed: February 9, 2012
    Publication date: November 21, 2013
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hidenori Nako, Ken Yamashita, Minoru Otsu, Mikihiro Sakata, Genichi Taniguchi
  • Publication number: 20130295412
    Abstract: A wire-form spray material, in particular for arc wire spraying, essentially comprising iron. The spray material is formed at least with carbon as a microalloy such that upon solidification of the spray material a fine pearlitic, bainitic, martensitic structure arises in which finely dispersed nitrides are present.
    Type: Application
    Filed: December 7, 2011
    Publication date: November 7, 2013
    Applicant: DAIMLER AG
    Inventors: Patrick Izquierdo, Eyuep Akin Oezdeniz
  • Publication number: 20130294961
    Abstract: A lead free free-cutting steel is described having the following composition in percent by weight: C 0.85-1.2 Si 0.1-0.6 Mn 0.4-1.2 P max 0.05 S 0.04-0.3 Cr max 2 Ni max 1 Mo max 0.5 Cu max 2 Al max 0.1 B max 0.008 Bi+Se+Te max 0.005 Ti+Nb+Zr+V max 0.2 balance Fe and normally occurring impurities. The steel is mainly intended for small/thin dimensions and/or low cutting speeds during manufacture of a product formed of the steel.
    Type: Application
    Filed: July 3, 2013
    Publication date: November 7, 2013
    Inventors: Mattias SANDSTRÖM, Ylva TROGEN, Lars KARLSSON
  • Publication number: 20130294959
    Abstract: Disclosed is a ferritic heat-resistant steel which has the following chemical composition (by weight): C: from 0.01% to less than 0.08%; Si: 0.30-1.0%; P: 0.02 or less; S: 0.010% or less; Mn: 0.2-1.2%; Ni: 0.3% or less; Cr: 8.0-11.0%; Mo: 0.1-1.2%; W: 1.0-2.5%; V: 0.10-0.30%; Nb: 0.02-0.12%; Co: 0.01-4.0%; N: 0.01-0.08%; B: not less than 0.001% and less than 0.010%; Cu: 0.3% or less; and Al: 0.010% or less, provided that the chemical composition satisfies the following equations: Mo(%)+0.5×W(%)=1.0-1.6, and C(%)+N(%)=0.02-0.15%, and which comprises a tempered martensite single-phase tissue produced by thermal refining and contains 30% by weight or less of 5 ferrite.
    Type: Application
    Filed: June 28, 2013
    Publication date: November 7, 2013
    Inventors: Toshio FUJITA, Takashi SATO, Kohji TAMURA
  • Publication number: 20130288838
    Abstract: A steel for a belt-type CVT pulley made of chromium steel or chromium molybdenum steel according to the present invention has a component composition that satisfies predetermined formulae regarding the mass % of Mn, Ni, Cr, Mo, Si, Nb and Ti. In addition, the steel for a belt-type CVT pulley contains, in terms of mass %, as essentially added elements, 0.15% to 0.25% of C, 0.40% to 1.00% of Mn, more than 1.80% and 2.20% or less of Cr, 0.005% to 0.030% of N, and 0.010% to 0.060% of Al, and as arbitrarily added elements, 0.20% or less of Si, 0.03% or less of P, 0.05% or less of S, 0.3% or less of Cu, 0.3% or less of Ni, and 0.2% or less of Mo, with the remainder being Fe and inevitable impurities.
    Type: Application
    Filed: April 23, 2013
    Publication date: October 31, 2013
    Applicants: DAIDO STEEL CO., LTD., HONDA MOTOR CO., LTD.
    Inventors: Gen KATO, Mitsuru FUJIMOTO, Hiroki TERADA, Sinichiro KATO, Katsuya YAMAGUCHI, Makoto HARITANI
  • Publication number: 20130272914
    Abstract: The steel wire material of the present invention contains 0.05 to 1.2% of C (mass %; same for the chemical components hereafter), 0.01 to 0.5% of Si, 0.1 to 1.5% of Mn, 0.02% or less (but not 0%) of P, 0.02% or less (but not 0%) of S, and 0.005% or less (but not 0%) of N, with the balance being iron and inevitable impurities. The wire material has a scale layer that is no thicker than 7.0 ?m or less. The scale layer has an FeO percentage of 30 to 80 vol % and an Fe2SiO4 percentage of less than 0.1 vol %. The scale layer that is formed will not peel when cooled after hot rolling or during storage and transport, but will easily peel during mechanical descaling.
    Type: Application
    Filed: January 6, 2012
    Publication date: October 17, 2013
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel. Ltd.)
    Inventors: Mikako Takeda, Shohei Nakakubo, Kazuhiko Kirihara, Masayuki Endo
  • Publication number: 20130272913
    Abstract: This steel wire material contains 0.05%-1.2% C (“%” means “% by mass,” same hereinafter for chemical components.), 0.01%-0.7% Si, 0.1%-1.5% Mn, 0.02% max. P (not including 0%), 0.02% max. S (not including 0%), and 0.005% max. N (not including 0%), with the remainder being iron and unavoidable impurities. The steel wire material has a scale 6.0-20 ?m thick and holes of an equivalent circle diameter of 1 ?m max. in said scale that occupy 10% by area max. Said scale does not detach in the cooling process after hot rolling or during storage or transportation but can readily detach during mechanical descaling.
    Type: Application
    Filed: December 9, 2011
    Publication date: October 17, 2013
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Mikako Takeda, Shohei Nakakubo, Kazuhiko Kirihara, Masayuki Endo
  • Patent number: 8540934
    Abstract: A lead free free-cutting steel is described having the following composition in percent by weight: C 0.85-1.2 Si 0.1-0.6 Mn 0.4-1.2 P max 0.05 S 0.04-0.3 Cr max 2 Ni max 1 Mo max 0.5 Cu max 2 Al max 0.1 B max 0.008 Bi+Se+Te max 0.005 Ti+Nb+Zr+V max 0.2 balance Fe and normally occurring impurities. The steel is mainly intended for small/thin dimensions and/or low cutting speeds during manufacture of a product formed of the steel.
    Type: Grant
    Filed: January 24, 2008
    Date of Patent: September 24, 2013
    Assignee: Sandvik Intellectual Property AB
    Inventors: Mattias Sandström, Ylva Trogen, Lars Karlsson
  • Publication number: 20130243641
    Abstract: A rolled steel bar or a wire rod for hot forging capable of coping with both bending/surface fatigue strength of components and machinability at a high level includes: a composition containing, in mass %, C: 0.1 to 0.25%, Si: 0.01 to 0.10%, Mn: 0.4 to 1.0%, S: 0.003 to 0.05%, Cr: 1.60 to 2.00%, Mo: 0.10% or less (including 0%), Al: 0.025 to 0.05%, and N: 0.010 to 0.025%, where a value of fn1 represented in a following formula (1) satisfies 1.82?fn1?2.10: fn1=Cr+2×Mo (1); impurities containing P: 0.025% or less, Ti: 0.003% or less, and O (oxygen): 0.002% or less; and a cross section in which a maximum value/a minimum value of an average ferrite grain diameter is 2.0 or less when measurement by observation is randomly carried out in 15 visual fields with an area per visual field set to be 62500 ?m2.
    Type: Application
    Filed: November 28, 2011
    Publication date: September 19, 2013
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yoshihiro Daitoh, Hideki Imataka, Masayuki Horimoto, Akira Shiga
  • Publication number: 20130243639
    Abstract: The present invention relates to a steel for extrusion tools characterized for lower cost and tempering resistance higher than that of conventional steel H13, whose chemical composition, in percentage by mass, comprises the following: Carbon between 0.40 and 0.60, Silicon below 1.0, Phosphorus below 0.030; Chromium between 2.5 and 4.5; Molybdenum between 0.5 and 0.7, considering that molybdenum can be replaced by tungsten in a ratio=2W/1Mo; Vanadium between 0.10 and 1.0; Manganese below 1.0; the remainder consisting essentially of Fe and inevitable deleterious substances. As an option to provide high hardness after nitriding, the Al content of the steel of the present invention can be ?1.0; for high toughness purposes, however, this Al content should be kept below 0.10.
    Type: Application
    Filed: March 4, 2011
    Publication date: September 19, 2013
    Inventors: Celso Antonio Barbosa, Rafael Agnelli Mesquita
  • Publication number: 20130243640
    Abstract: There is provided steel for wheel having a chemical composition consisting of, by mass percent, C: 0.65 to 0.84%, Si: 0.02 to 1.00%, Mn: 0.50 to 1.90%, Cr: 0.02 to 0.50%, V: 0.02 to 0.20%, and S: 0.04% or less, in which 34?2.7+29.5×C+2.9×Si+6.9×Mn+10.8×Cr+30.3×Mo+44.3×V?43, and 0.76×exp(0.05×C)×exp(1.35×Si)×exp(0.38×Mn)×exp(0.77×Cr)×exp(3.0×Mo)×exp(4.6×V)25, the balance being Fe and impurities, and the impurities containing P: 0.05% or less, Cu: 0.20% or less, and Ni: 0.20% or less. This steel for wheel is excellent in balance between the wear resistance, rolling contact fatigue resistance and the spalling resistance, and can give a long life to the wheel.
    Type: Application
    Filed: November 18, 2011
    Publication date: September 19, 2013
    Applicant: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Yuichiro Yamamoto, Yukiteru Takeshita, Takanori Kato, Kentaro Kiriyama
  • Publication number: 20130240093
    Abstract: A steel for high-strength spring has an Ac3 transformation temperature as an indicator of the decarburization performance, which is calculated by Equation (1) below, is from 859 to 885° C., a maximum hardened diameter DI as an indicator of the hardening performance, which is calculated by Equation (2) below, is from 70 to 238 mm, and a temper hardness HRC as an indicator of the spring performance, which is calculated by Equation (3) below, is from 50 to 55. Ac3=910?203×?{square root over (C)}?15.2Ni+44.7Si+104V+31.5Mo+13.1W??(1) DI=DO×fSi×fMn×fP×fS×fCu×fNi×fCr??(2) HRC=38.99+17.48C+2.55Si?2.28Ni+2.37Cr+8.04Ti??(3) wherein, D0=8.65×?{square root over (C)}, fSi=1+0.64×% Si, fMn=1+4.10×% Mn, fP=1+2.83×% P, fS=1?0.62×% S, fCu=1+0.27×% Cu, fNi=1+0.52×% Ni, and fCr=1+2.33×% Cr.
    Type: Application
    Filed: May 2, 2013
    Publication date: September 19, 2013
    Applicant: NHK SPRING CO., LTD.
    Inventors: Hideki OKADA, Akira TANGE, Koichi TANGO, Isao SUMIYOSHI
  • 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: 20130127100
    Abstract: Provided are: a steel wire rod material for a high-strength spring, which does not undergo the increase in deformation resistance arising from the increase in hardness and can exhibit good wire-drawing processability and the like even when a heat treatment, which deteriorates productivity, is eliminated or a simplified and rapid heat treatment is employed instead; a useful method for producing the steel wire rod material for a high-strength spring; a high-strength spring produced using the steel wire rod material for a high-strength spring as a material; and others. This steel wire rod material for a high-strength spring is a steel wire rod material that has been hot-rolled already, and has a texture having a specified chemical composition and mainly composed of pearlite, wherein the average value (Pave) of the pearlite nodule size numbers and the standard deviation (P?) of the pearlite nodule size numbers fulfill the following formulae (1) and (2), respectively: 9.5?Pave?12.0;??(1) and 0.2?P??0.
    Type: Application
    Filed: August 30, 2011
    Publication date: May 23, 2013
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Tomonobu Ishida, Nao Yoshihara, Shuhei Kitamura
  • 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: 20130078135
    Abstract: The present invention is related to a steel product of the weathering steel type, i.e. a product exhibiting increased corrosion resistance after having been exposed to the outside environment for a given time. According to the invention, the steel product is defined by a composition consisting of (in wt %):—Carbon between 0.03 and 0.2,—Manganese between 0.5 and 2,—Copper between 0 and 0.5,—Ti between 0 and 0.1,—Cr between 0 and 0.5,—Nickel between 0 and 0.2,—Niobium between 0 and 0.1,—Nitrogen between 0 and 0.01,—Sulphur between 0 and 0.01, Phosphor between 0 and 0.01,—Aluminium higher than 0 and maximum 1.5,—Silicon between 0.25 and 1.5, the balance being Fe and accidental impurities, and wherein the sum of the Al and Si levels is higher than about 0.85 wt %.
    Type: Application
    Filed: March 29, 2010
    Publication date: March 28, 2013
    Inventors: Joachim Antonissen, Eddy De Grave, Julieth Alexandra
  • Publication number: 20130037176
    Abstract: A high strength, high toughness steel alloy is disclosed. The alloy has the following weight percent composition. Element C 0.30-0.47 Mn 0.8-1.3 Si 1.5-2.5 Cr 1.5-2.5 Ni 3.0-5.0 Mo + ½ W 0.7-0.9 Cu 0.70-0.90 Co ?0.01 max. V + ( 5/9) × Nb 0.10-0.25 Ti 0.005 max. Al 0.015 max. Fe Balance Included in the balance are the usual impurities found in commercial grades of steel alloys produced for similar use and properties including not more than about 0.01% phosphorus and not more than about 0.001% sulfur. Also disclosed is a hardened and tempered article that has very high strength and fracture toughness. The article is formed from the alloy having the broad weight percent composition set forth above. The alloy article according to this aspect of the invention is further characterized by being tempered at a temperature of about 500° F. to 600° F.
    Type: Application
    Filed: October 5, 2012
    Publication date: February 14, 2013
    Applicant: CRS HOLDINGS, INC.
    Inventor: CRS HOLDINGS, INC.
  • Publication number: 20130039803
    Abstract: Disclosed is a high-strength steel plate having a predetermined chemical composition, in which a microstructure of the steel plate at a depth of one-fourth to one half the thickness from a surface has an area fraction of bainite of 90% or more, an average lath width of bainite of 3.5 ?m or less, and a maximum equivalent circle diameter of martensite-austenite constituents in bainite of 3.0 ?m or less. The steel plate exhibits high strengths and good drop weight properties and is useful as structural materials for offshore structure, ships, and bridges, as well as materials for pressure vessels in nuclear power plants.
    Type: Application
    Filed: March 15, 2011
    Publication date: February 14, 2013
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hiroyuki Takaoka, Eiichi Tamura
  • Publication number: 20130028782
    Abstract: Provided is a welding metal in which the chemical component composition thereof is appropriately controlled; an A value that is specified by a predetermined relational expression satisfies the requirement of being 3.8% to 9.0%; an X value that is specified by a predetermined relational expression satisfies the requirement of being 0.5% or greater; the area percentage of carbide particles having a circle-equivalent diameter of 0.20 ?m or greater in the welding metal is 4.0% or less; and the number of carbide particles having a circle-equivalent diameter of 1.0 ?m or greater is 1000 particles/mm2 or less. This welding metal, which can exhibit not only high strength but also good low-temperature toughness and good drop-weight characteristics, is useful as a material for a pressure vessel in a nuclear power plant.
    Type: Application
    Filed: April 8, 2011
    Publication date: January 31, 2013
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hidenori Nako, Yoshitomi Okazaki, Ken Yamashita, Minoru Otsu, Hideaki Takauchi
  • Publication number: 20130025747
    Abstract: A steel for an induction hardening including, by mass %, C: more than 0.75% to 1.20%, Si: 0.002 to 3.00%, Mn: 0.20 to 2.00%, S: 0.002 to 0.100%, Al: more than 0.050% to 3.00%, P: limited to 0.050% or less, N: limited to 0.0200% or less, O: limited to: 0.0030% or less, and the balance composing of iron and unavoidable impurities, wherein an Al content and a N content satisfy, by mass %, Al?(27/14)×N>0.050%.
    Type: Application
    Filed: February 15, 2011
    Publication date: January 31, 2013
    Inventors: Manabu Kubota, Toshiharu Aiso, Kei Miyanishi
  • Publication number: 20130022833
    Abstract: A silicon steel sheet formed from a silicon steel alloy composition includes, in parts by weight, iron, carbon present in an amount of from about 0.002 to about 0.06, silicon present in an amount of from about 1.5 to about 4.0, aluminum present in an amount of from about 0.1 to 1.0, titanium present in an amount of less than or equal to about 0.03, vanadium present in an amount of less than or equal to about 0.005, and cobalt present in an amount of from about 0.001 to about 5.0 based on 100 parts by weight of the composition. Neither niobium nor zirconium is present in the composition. A silicon steel sheet system including the silicon steel sheet and a coating disposed thereon, and an electromagnetic machine having a magnetic core including a plurality of sheets stacked adjacent one another are also disclosed.
    Type: Application
    Filed: July 22, 2011
    Publication date: January 24, 2013
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS LLC
    Inventor: Shekhar G. Wakade
  • Publication number: 20130017117
    Abstract: A bearing steel contains C: 0.56% by mass or more and 0.70% by mass or less, Si: 0.15% by mass or more and less than 0.50% by mass, Mn: 0.60% by mass or more and 1.50% by mass or less, Cr: 0.50% by mass or more and 1.10% by mass or less, P: 0.025% by mass or less, S: 0.025% by mass or less, Al: 0.005% by mass or more and 0.500% by mass or less, O: 0.0015% by mass or less, N: 0.0030% by mass or more and 0.015% by mass or less, and a remainder of Fe and incidental impurities. The bearing steel has a composition such that the eutectic carbide formation index Ec satisfies 0<Ec?0.25.
    Type: Application
    Filed: November 30, 2010
    Publication date: January 17, 2013
    Applicant: JFE Steel Corporation
    Inventors: Minoru Honjo, Kazukuni Hase, Hideto Kimura
  • 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
  • Publication number: 20120321503
    Abstract: An ingot steel for bearings has a composition containing C: 0.56% by mass or more and 0.70% by mass or less, Si: 0.15% by mass or more and less than 0.50% by mass, Mn: 0.60% by mass or more and 1.50% by mass or less, Cr: 0.50% by mass or more and 1.10% by mass or less, P: 0.025% by mass or less, S: 0.025% by mass or less, Al: 0.005% by mass or more and 0.500% by mass or less, O: 0.0015% by mass or less, N: 0.0030% by mass or more and 0.015% by mass or less, and a remainder of Fe and incidental impurities, wherein eutectic carbide formation index Ec satisfies 0<Ec?0.25.
    Type: Application
    Filed: November 30, 2010
    Publication date: December 20, 2012
    Inventors: Minoru Honjo, Kazukuni Hase, Hideto Kimura
  • Publication number: 20120294752
    Abstract: Provided is a welding metal in which a predetermined chemical component composition is satisfied, the A value as specified by formula (1) is 3.8% to 9.0%, and the surface area percentage of carbide having a circle-equivalent diameter of 0.20 ?m or greater in the welding metal is 4.0% or less. A value=0.8×[C]?0.05×[Si]+0.5×[Mn]+0.5×[Cu]+[Ni]?0.5×[Mo]+0.2×[Cr]??(1) (Provided that [C], [Si], [Mn], [Cu], [Ni], [Mo] and [Cr] are the C, Si, Mn, Cu, Ni, Mo and Cr content (by mass percent), respectively) The welding metal is useful as a material for a pressure vessel of a nuclear power plant as the welding metal is high in strength and has good low-temperature toughness and drop-weight characteristics.
    Type: Application
    Filed: January 24, 2011
    Publication date: November 22, 2012
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hidenori Nako, Yoshitomi Okazaki, Ken Yamashita, Minoru Otsu, Hideaki Takauchi
  • Publication number: 20120216904
    Abstract: A method of making an UOE steel pipe having excellent deformability and low-temperature toughness includes providing a steel composition with a controlled composition consisting essentially of C: 0.03-0.07%, Si: 0.05-0.50%, Mn: 1.6-2.2%, P: at most 0.020%, S: at most 0.003%, Cu: 0.20-0.60%, Cr: at most 0.10%, Ni: 0.20-0.80%, Nb: 0.005-0.030%, Ti: 0.005-0.030%, N: at most 0.0070%, Al: 0.005-0.060%, and a remainder of Fe and impurities, a hardenability index Pcm of at most 0.22%, Cu+Cr+Ni is 0.4-1.5%, and Nb+Mo+V is at most 0.05%. The pipe has a yield strength in the longitudinal direction of at least 480 MPa, a yield-tensile ratio of at most 85% and a Charpy absorbed energy of the heat affected zone at ?40° C. of at least 40 J.
    Type: Application
    Filed: May 4, 2012
    Publication date: August 30, 2012
    Applicant: Sumitomo Metal Industries, Ltd.
    Inventors: Nobuaki TAKAHASHI, Akio YAMAMOTO, Masahiko HAMADA
  • Publication number: 20120183431
    Abstract: A structural steel material contains C: 0.020% or more and less than 0.140%, Si: 0.05% or more and 2.00% or less, Mn: 0.20% or more and 2.00% or less, P: 0.005% or more and 0.030% or less, S: 0.0001% or more and 0.0200% or less, Al: 0.001% or more and 0.100% or less, Cu: 0.10% or more and 1.00% or less, Ni: 0.10% or more and less than 0.65%, and W: 0.05% or more and 1.00% or less, and one or both of Nb: 0.005% or more and 0.200% or less and Sn: 0.005% or more and 0.200% or less, the balance being iron and unavoidable impurities.
    Type: Application
    Filed: September 28, 2010
    Publication date: July 19, 2012
    Applicant: JFE STEEL CORPORATION
    Inventors: Shinichi Miura, Isamu Kage, Masatsugu Murase, Toshiyuki Hoshino
  • Patent number: 8206521
    Abstract: According to one embodiment, a high-strength stabilizer steel for vehicles having excellent corrosion resistance and low-temperature toughness, containing 0.07 to 0.20% C, more than 0.6% and 1.5% or less Si, 1 to 3% Mn, 0.1 to 1.0% Cr, 0.005 to 0.080% sAl, 0.005 to 0.060% Ti, 0.005 to 0.060% Nb, 0.070% or less Ti+Nb, 150 ppm or less N, 0.035% or less P, 0.035% or less S, 0.01 to 1.00% Cu, 0.01 to 1.00% Ni, the remainder being Fe, and unavoidable impurities, wherein a structure before molding a stabilizer is any one of a bainite, a martensite, and a mixed structure of bainite/martensite and an original austenitic crystal grain size number after a heat treatment of the stabilizer is Gh 9 or more.
    Type: Grant
    Filed: August 11, 2011
    Date of Patent: June 26, 2012
    Assignees: NHK Spring Co., Ltd., JFE Bars & Shapes Corporation
    Inventors: Katsuhiko Kikuchi, Kunikazu Tomita, Yutaka Tamai, Kazuaki Hattori, Kanji Inoue, Akira Tange, Norihiko Mori, Yurika Goto, Kiyoshi Kurimoto
  • 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: 20120070330
    Abstract: A high-strength steel sheet comprises, by weight, not less than 0.25% and not more than 0.5% of C, not less than 4% and not more than 14% of Mn, not less than 6.5% and not more than 9.5% of Cr, and not less than 0.3% and not more than 3% of Si. The high-strength steel sheet satisfies the following formulas 1 and 2 and mainly consists of austenite, and the high-strength steel sheet has yield strength of not less than 1000 MPa and total elongation of not less than 20%. 12?2.0Si+5.5Al+Cr+1.5Mo?25 ??(1) 13 ?30C+0.5Mn+0.
    Type: Application
    Filed: November 5, 2008
    Publication date: March 22, 2012
    Applicants: HONDA MOTOR CO., LTD
    Inventors: Masashi Ishii, Sven Leonhardt, Yoshitaka Okitsu, Klaus Brokmeier, Georg Frommeyer, Ursula Frommeyer, Astrid Frommeyer
  • Publication number: 20120021246
    Abstract: To provide weld metal that has a high strength and toughness in the as-welded condition or in the annealed condition. The weld metal of the present invention contains by weight %, C: 0.04-0.15%, Si: 0.50% or less, Mn: 1.0-1.9%, Ni: 1.0-4.0%, Cr: 0.10-1.0%, Mo: 0.20 to 1.2%, Ti: 0.010-0.060%, Al: 0.030% or less, O: 0.15-0.060%, N: 0.010% or less, Fe and inevitable impurities as the remaining contents. The weld metal is further characterized by the fact that the ratio of Ti content (%) to Si content (%) i.e.,[compound type Ti]/[compound type Si] is more than 1.5, and the number A defined by the following formula is 0.50 or more, wherein A=[Ti]/([O]?1.1×[Al]+0.05×[Si]).
    Type: Application
    Filed: March 25, 2010
    Publication date: January 26, 2012
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO
    Inventors: Hidenori Nako, Yoshitomi Okazaki, Ken Yamashita, Hideaki Takauchi, Minoru Otsu
  • Publication number: 20110318605
    Abstract: A high strength steel sheet contains, in percent by mass, 0.03 to 0.2% of C, 0.5 to 2.5% of Si, 1 to 3.0% of Mn, 0.01 to 0.5% of Cr, 0.01 to 0.5% of Mo, 0.02 to 0.15% of Al, 0.15% or less of Ti, 0.15% or less of No, and 0.15% or less of V; wherein the remainder includes Fe and inevitable impurities, and the content of Si satisfies the following formula (1), ?-4.1[Si]?-2.4??(1), provided, ?=6.9×([C]+[Mn]/6+[Cr]/5+[Mo]/4+[Ti]/15+[Nb]/17+[V]/14)1/2 is given, wherein [ ] shows the quantity (mass percent) of each element contained in the steel sheet. The high strength steel sheet is improved in formability (particularly, elongation), and excellent in balance between strength and elongation.
    Type: Application
    Filed: September 6, 2011
    Publication date: December 29, 2011
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Yuichi FUTAMURA, Katsuhiro Yamamoto, Masaaki Miura
  • Publication number: 20110305593
    Abstract: The present invention provides a type of steel and a coupler made from same, comprising the following compositions in percentages by weight: carbon: 0.24-0.32%, silicon: 0.20-0.50%, manganese: 1.30-1.70%, phosphorus: less than or equal to 0.02%, sulphur: less than or equal to 0.02%, copper: less than or equal to 0.30%, chromium: 0.50-0.80%, nickel: 0.40-0.70%, molybdenum: 0.25-0.45%, aluminium: 0.02-0.08%, and the remainders are iron and other inevitable elements. The steel of the present invention is advantaged in high strength and excellent toughness and therefore the mechanical property thereof is better than the standard of conventional grade E steel.
    Type: Application
    Filed: June 28, 2011
    Publication date: December 15, 2011
    Applicants: MUDANJIANG JINYUAN COUPLER AND DRAFT GEAR MANUFACTURING CO., LTD., QIQIHAR RAILWAY ROLLING STOCK CO., LTD.
    Inventors: XIAOFENG QIN, Chunguo Tao, Yang Lu, Limin Xiao, Baoli Wen, Xunqian Wei
  • Patent number: 8071017
    Abstract: A cobalt-free low cost high strength martensitic stainless steel, with concentration of Ni up to 3.0% and Mo up to 1.0% of weight, has HRC of 53, UTS of 297 ksi, YS of 220 ksi, Charpy V-notch impact energy of 17.8 ft-lb, corrosion resistance in salt spray test ASTM 117. The steel was melted in an open induction furnace and vacuum arc remelting (VAR) and/or electroslag remelting (ESR) were not used to refine the steel. Further processing included homogenized annealing, hot rolling, and recrystallization annealing. The steel was heat treated by oil quenching, refrigeration, and low tempering. The steel has a microstructure consisting essentially of small packets of fine martensite laths, retained austenite, and carbides as centers of growth of the martensite laths. The cost and energy in making the steel are substantially reduced.
    Type: Grant
    Filed: October 25, 2008
    Date of Patent: December 6, 2011
    Inventors: Vladimir A. Fedchun, Gregory Vartanov
  • Publication number: 20110290382
    Abstract: According to one embodiment, a high-strength stabilizer steel for vehicles having excellent corrosion resistance and low-temperature toughness, containing 0.07 to 0.20% C, more than 0.6% and 1.5% or less Si, 1 to 3% Mn, 0.1 to 1.0% Cr, 0.005 to 0.080% sAl, 0.005 to 0.060% Ti, 0.005 to 0.060% Nb, 0.070% or less Ti+Nb, 150 ppm or less N, 0.035% or less P, 0.035% or less S, 0.01 to 1.00% Cu, 0.01 to 1.00% Ni, the remainder being Fe, and unavoidable impurities, wherein a structure before molding a stabilizer is any one of a bainite, a martensite, and a mixed structure of bainite/martensite and an original austenitic crystal grain size number after a heat treatment of the stabilizer is Gh 9 or more.
    Type: Application
    Filed: August 11, 2011
    Publication date: December 1, 2011
    Applicants: JFE BARS & SHAPES CORPORATION, NHK SPRING CO., LTD.
    Inventors: Katsuhiko KIKUCHI, Kunikazu Tomita, Yutaka Tamai, Kazuaki Hattori, Kanji Inoue, Akira Tange, Norihiko Mori, Yurika Goto, Kiyoshi Kurimoto
  • Publication number: 20110287280
    Abstract: A cold-rolled steel sheet has a chemical composition of C: 0.12% to 0.3%, Si: 0.5% or less, Mn: less than 1.5%, Al: 0.15% or less, N: 0.01% or less, P: 0.02% or less, and S: 0.01% or less, with the remainder including iron and inevitable impurities and has a martensite single-phase structure as its steel microstructure. In a surface region of the steel sheet from the surface to a depth one-tenth the gauge, the number density of n-ary groups of inclusions determined by specific n-th determinations is 120 or less per 100 cm2 of a rolling plane, where the distance in steel sheet rolling direction between outermost surfaces of two outermost particles of the group of inclusions is 100 ?m or more. The steel sheet is a high-strength cold-rolled steel sheet which has a sufficiently minimized rate of bending fracture starting from inclusions and thereby has excellent bending workability.
    Type: Application
    Filed: May 3, 2011
    Publication date: November 24, 2011
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Atsuhiro SHIRAKI, Sae Hamamoto, Yukihiro Utsumi, Tetsuji Hoshika, Yuichi Futamura
  • Publication number: 20110274578
    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: Application
    Filed: January 15, 2010
    Publication date: November 10, 2011
    Inventors: Atsushi Mizuno, Masayuki Hashimura, Kei Miyanishi, Shuji Kozawa
  • Publication number: 20110273054
    Abstract: In a method for manufacture of electrical steel a liquid steel mixture is created with a specified mixture chemistry. A continuous casting is performed to convert the liquid steel mixture to a slab. Hot roll steel band is created from the slab which is then pickled and hot band annealed, and then a cold rolled steel strip is formed. In a continuous annealing line, the cold rolled strip is annealed to achieve a partial recrystallization with a smaller grain size than would be the grain size with a complete recrystallization. Electrical steel created by the method is used for rotors and matching stators of a motor with properties at high strength and low electrical losses.
    Type: Application
    Filed: May 4, 2010
    Publication date: November 10, 2011
    Inventor: Gwynne Johnston
  • Patent number: 8043407
    Abstract: It is an object of the present invention to provide a similar composition metal type welding solid wire capable of forming a welded joint having excellent cryogenic characteristics, such as ensuring a low-temperature toughness equivalent to that of the cryogenic base metal, and in addition, further having a high crack initiation resistance, and a weld metal thereof. The welding solid wire of the present invention is an iron base welding solid wire including carbon: 0.10 mass % or less (not inclusive of 0%), silicon: 0.15 mass % or less (not inclusive of 0%), nickel: 8.0 to 15.0 mass %, manganese: 0.10 to 0.80 mass %, and Al: 0.1 mass % or less (not inclusive of 0%), and oxygen in an amount of 150 ppm or less (inclusive of 0), characterized by including: a REM: 0.005 to 0.040 mass %, or chromium: 4.0 mass % or less (not inclusive of 0%).
    Type: Grant
    Filed: October 2, 2008
    Date of Patent: October 25, 2011
    Assignee: Kobe Steel, Ltd.
    Inventors: Hidenori Nako, Hiroyuki Takeda, Yoshitomi Okazaki, Kazuyuki Suenaga, Kohjiroh Nakanishi
  • Publication number: 20110226386
    Abstract: A steel characterized in that its composition is percentages by weight: C=0.18-0.30% Co=1.5-4% Cr=2-5% Al=1-2% Mo+W/2=1-4% V=traces-0.3% Nb=traces-0.1% B=traces-30 ppm Ni=11-16% where Ni?7+3.5 Al Si=traces-1.0% Mn=traces-4.0% Ca=traces-20 ppm Rare earths=traces-100 ppm if N?10 ppm, Ti+Zr/2=traces-100 ppm where Ti+Zr/2?10 N if 10 ppm<N?20 ppm, Ti+Zr/2=traces-150 ppm O=traces-50 ppm N=traces-20 ppm S=traces-20 ppm Cu=traces-1% P=traces-200 ppm the remainder being iron and inevitable impurities resulting from the smelting. A process for manufacturing a part from this steel, and part thus obtained.
    Type: Application
    Filed: July 8, 2009
    Publication date: September 22, 2011
    Inventor: François Roch
  • Publication number: 20110223441
    Abstract: The invention concerns a very high mechanical strength steel, whereof the chemical composition comprises in wt. %: 0.060%=C=0.250%; 0.400%=Mn=0.950%; Si=0.300%; Cr=0.300%; 0.100%=Mo=0.500%; 0.020%=AI=0.100%; P=0.100%; B=0.010%; Ti=0.050%, the rest being iron and impurities resulting from preparation. The invention also concerns a method for making a sheet of said steel coated with zinc or zinc alloy.
    Type: Application
    Filed: May 20, 2011
    Publication date: September 15, 2011
    Applicant: USINOR
    Inventors: Antoine MOULIN, Jean-Luc LAPOINTE
  • Publication number: 20110217566
    Abstract: Corrosion-resistant steel for chimney/flue use in natural gas-fired or liquefied petroleum gas-fired plants, containing C: 0.005% to 0.030%, Si: 0.18% to 0.50%, Mn: 1.50% to less than 3.00, P: 0.030% or less, S: 0.0050% or less, Cr: 4.0% to 9.0%, Al: 0.20% to 1.50%, and N: 0.020% or less and able to prevent advanced pitting or other localized corrosion and the resultant hole formation and rust aerial dispersal is provided.
    Type: Application
    Filed: March 19, 2010
    Publication date: September 8, 2011
    Inventors: Matoko Nagasawa, Kenji Katoh, Naoki Saitoh, Masayuki Kodama, Mutsuto Tanaka, Fumiaki Nakamura
  • Publication number: 20110189047
    Abstract: Railroad rail steels having a pearlitic structure and containing 0.720 to 0.860 wt % carbon; 1.000 to 1.280 wt % manganese; 0.450 to 1.000 wt % silicon; 0.010 to 0.100 wt % copper; 0.150 to 0.280 wt % chromium; 0.0010 to 0.0500 wt % aluminum; 0.050 to 0.120 wt % nickel; 0.100 to 0.260 wt % molybdenum; 0.100 to 0.210 wt % vanadium; 0.0010 to 0.0065 wt % nitrogen; 0.0010 to 0.0080 wt % phosphorus; 0.0010 to 0.0040 wt % sulfur; and 0.0100 to 0.0350 wt % niobium with the remainder of said steel being iron, can be used to make railway rails that are particularly resistant to rolling contact fatigue and, hence, shelling.
    Type: Application
    Filed: February 2, 2010
    Publication date: August 4, 2011
    Applicant: TRANSPORTATION TECHNOLOGY CENTER, INC.
    Inventors: Daniel Szablewski, Francisco C. Robles Hernandez, C. Isaac Garcia, Semih Kalay, Anthony J. Deardo, Raymundo Ordoniez
  • Publication number: 20110165011
    Abstract: A high strength, high toughness steel alloy is disclosed. The alloy has the following weight percent composition. Element C 0.30-0.47 Mn 0.8-1.3 Si 1.5-2.5 Cr 1.5-2.5 Ni 3.0-5.0 Mo + ½ W 0.7-0.9 Cu 0.70-0.90 Co ?0.01 max. V + ( 5/9) × Nb 0.10-0.25 Ti 0.005 max. Al 0.015 max. Fe Balance Included in the balance are the usual impurities found in commercial grades of steel alloys produced for similar use and properties including not more than about 0.01% phosphorus and not more than about 0.001% sulfur. Also disclosed is a hardened and tempered article that has very high strength and fracture toughness. The article is formed from the alloy having the broad weight percent composition set forth above. The alloy article according to this aspect of the invention is further characterized by being tempered at a temperature of about 500° F. to 600° F.
    Type: Application
    Filed: January 28, 2011
    Publication date: July 7, 2011
    Inventor: Paul M. Novotny
  • Publication number: 20110103996
    Abstract: A continuous cast slab includes the following component: by mass %, C: 0.01˜0.3%, Si: 0.05˜0.5%, Mn: 0.4˜2%, P: 0.03% or less, S: 0.03 or less, Al: 0.005˜0.03%, Ni: 0.2˜2%, O: 0.006% or less, and N: 0.006% or less; wherein the balance is composed of Fe and inevitable impurities; wherein a structure in steel in a region within at least 2 mm from a broad surface is composed of ferrite and pearlite and a equivalent circular diameter of ferrite grains in the region is equal to or shorter than 30 ?m.
    Type: Application
    Filed: July 15, 2009
    Publication date: May 5, 2011
    Inventors: Akihito Kiyose, Toshiyuki Kajitani, Mineo Niizuma, Yasuhiko Otani
  • Publication number: 20110091348
    Abstract: A steel for heat treatment, which exhibits high strength and high toughness even when the heat treatment (such as quenching and tempering) of the steel is conducted under conventional conditions in an after stage. The steel for heat treatment contains C: 0.10 to 0.70 mass %, Mn: 0.1 to 3.0 mass %, Al: 0.005 to 2.0 mass %, P: 0.050 mass % or less, S: 0.50 mass % or less, O: 0.0030 mass or less, N: 0.0200 mass % or less, and one or more selected from the group consisting of Ti: 0.30 mass % or less and Nb: 0.30 mass or less with the balance being Fe and unavoidable impurities, and has a TH value of 1.0 or above as calculated according to the formula: ({Ti}/48+{Nb}/93) 104 and grain diameters of 10 ?m or below. {Ti} and {Nb} refer respectively to the contents of Ti and Nb in precipitates of 5 to 100 nm in size as determined about their respective extraction residues.
    Type: Application
    Filed: June 17, 2009
    Publication date: April 21, 2011
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hitoshi Hatano, Takuya Kochi
  • Patent number: 7922968
    Abstract: Provided are a steel sheet for an automotive muffler and a method for producing the steel sheet. The steel sheet includes 0.01% by weight or less of C, 0.1 to 0.3% by weight of Si, 0.3 to 0.5% by weight of Mn, 0.015% by weight or less of P, 0.015% or less by weight of S, 0.02 to 0.05% by weight of Al, 0.004% or less of N, 0.2 to 0.6% by weight of Cu, 0.01 to 0.04% by weight of Co, and a remainder of Fe and unavoidable impurities. The method includes 0.01% by weight or less of C, 0.1 to 0.3% by weight of Si, 0.3 to 0.5% by weight of Mn, 0.015% by weight or less of P, 0.015% or less by weight of S, 0.02 to 0.05% by weight of Al, 0.004% or less of N, 0.2 to 0.6% by weight of Cu, 0.01 to 0.
    Type: Grant
    Filed: October 25, 2006
    Date of Patent: April 12, 2011
    Assignee: Posco
    Inventors: Won-Ho Son, Jai-Ik Kim, Seung-Hee Lee, Jeong-Bong Yoon, Hee-Man Son
  • Publication number: 20110074076
    Abstract: A high-strength spring steel and a spring are provided that have superior corrosion fatigue strength. The spring steel comprises, in mass percent, 0.35-0.55% C, 1.60-3.00% Si, 0.20-1.50% Mn, 0.10-1.50% Cr, and at least one of 0.40-3.00% Ni, 0.05-0.50% Mo and 0.05-0.50% V, the balance being substantially Fe and incidental elements and impurities.
    Type: Application
    Filed: September 28, 2010
    Publication date: March 31, 2011
    Applicant: CHUO HATSUJO KABUSHIKI KAISHA
    Inventors: Takanori Kuno, Tomohiro Nakano, Takayuki Sakakibara, Masami Wakita, Shingo Mimura
  • Patent number: 7914629
    Abstract: The present invention provides high strength thick steel plate superior in crack arrestability high in strength, free of deterioration of HAZ toughness, and free of anisotropy, that steel plate containing, by mass %, C: 0.03 to 0.15%, Si: 0.1 to 0.5%, Mn: 0.5 to 2.0%, P: ?0.02%, S: ?0.01%, Al: 0.001 to 0.1%, Ti: 0.005 to 0.02%, Ni: 0.15 to 2%, and N: 0.001 to 0.008% and having a balance of iron and unavoidable impurities as chemical components, having a microstructure of a ferrite and/or pearlite structure with bainite as a matrix phase, and having an average circle equivalent diameter of crystal grains with a crystal misorientation angle of 15° or more of 15 ?m or less in the regions of 10% of plate thickness from the front and rear surfaces and of 40 ?m or less in the other region including the center part of plate thickness.
    Type: Grant
    Filed: April 13, 2007
    Date of Patent: March 29, 2011
    Assignee: Nippon Steel Corporation
    Inventors: Kiyotaka Nakashima, Masanori Minagawa, Kouji Ishida, Akira Ito