Nine Percent Or More Chromium Containing Patents (Class 148/325)
  • Patent number: 8157930
    Abstract: A martensitic stainless steel comprising C: 0.01-0.10%, Si: 0.05-1.0%, Mn: 0.05-1.5%, P: not more than 0.03%, S: not more than 0.01%, Cr: 9-15%, Ni: 0.1-4.5%, Al: not more than 0.05% and N: not more than 0.1% in mass %, and further comprising at least one of Cu: 0.05-5% and Mo: 0.05-5%, the residual being Fe and impurities, is provided, wherein the contents of Cu and Mo satisfy the following formula (a) or (b), 0.2%?Mo+Cu/4?5%??(a) 0.55%?Mo+Cu/4?5%??(b) and wherein the hardness is 30-45 in HRC and the carbide amount in grain boundaries of the prior austenite is not more than 0.5 volume %. The marensitic stainless steel has excellent properties regarding the sulfide stress cracking resistance, the resistance to corrosive wear and the localized corrosion.
    Type: Grant
    Filed: March 12, 2004
    Date of Patent: April 17, 2012
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Hisashi Amaya, Kunio Kondo, Masakatsu Ueda, Keiichi Nakamura, Takahiro Kushida, Kazuyo Kushida, legal representative
  • Publication number: 20120085513
    Abstract: A ferritic stainless steel material for brazing without grain coarsening has a partially recrystallized structure and composition comprising, in % by mass, C:0.03% or less, Si: more than 0.1 to 3%, Mn: 0.1 to 2%, Cr: 10 to 35%, Nb: 0.2 to 0.8%, N: 0.03% or less, if necessary, at least one of Mo, Cu, V and W: 4% or less in total, at least one of Ti and Zr: 0.5% or less in total, at least one of Ni and Co: 5% or less in total, or at least one of Al: 6% or less, REM (rare earth metal): 0.2% or less and Ca: 0.1% or less, the remainder being Fe and unavoidable impurities, wherein area ratio in percentage of recrystallized grains formed by heating after cold working is from 10 to 80%.
    Type: Application
    Filed: June 14, 2010
    Publication date: April 12, 2012
    Applicant: NISSHIN STEEL CO., LTD.
    Inventors: Manabu Oku, Sadayuki Nakamura, Yoshiaki Hori
  • Publication number: 20120085310
    Abstract: An engine valve comprising a chromiferous steel and a protective surface layer (5) which consists of iron chrome oxide. A method for manufacture of an engine valve with a protective layer includes an engine component of a chromiferous steel which is heated (200) at a predetermined temperature for a predetermined time so that a layer (5) of iron chrome oxide is formed on the engine component's surface, and the engine component is then cooled (300) to room temperature.
    Type: Application
    Filed: June 14, 2010
    Publication date: April 12, 2012
    Inventor: Magnus Bergström
  • Patent number: 8152937
    Abstract: Disclosed is a ferritic stainless steel sheet which has excellent corrosion resistance against sulfuric acid in the high-temperature environment and shows less surface roughness at a bent part which is bent at 90° or more. Specifically disclosed is a ferritic stainless steel sheet which has the following chemical composition: C: 0.02 mass % or less, Si: 0.05 to 0.8 mass %, Mn: 0.5 mass % or less, P: 0.04 mass % or less, S: 0.010 mass % or less, Al: 0.10 mass % or less, Cr: 20 to 24 mass % Cu: 0.3 to 0.8 mass %, Ni: 0.5 mass % or less, Nb: 0.20 to 0.55 mass %, and N: 0.02 mass % or less, with the remainder being Fe and unavoidable impurities; and which has such a structure that the maximum particle diameter of an S-containing precipitate is 5 ?m or smaller.
    Type: Grant
    Filed: June 18, 2008
    Date of Patent: April 10, 2012
    Assignee: JFE Steel Corporation
    Inventors: Tomohiro Ishii, Yoshimasa Funakawa, Takumi Ujiro, Masayuki Ohta
  • Publication number: 20120080124
    Abstract: The invention provides an alloy steel having the following composition: Ni 5-14 wt %; Cr 4-16 wt %; Co 7-14 wt %; Mo 1-5 wt %; W 0-5 wt %; Ti 0-0.8 wt %; Al 0.1-3 wt %; the balance being Fe save for incidental impurities. This provides an ultra-high strength corrosion resistant steel with good toughness, which does not significantly creep at temperatures up to 450° C. The high quantity of alloying to elements, particularly chromium, also gives the alloy good corrosion resistance. The alloy is particularly suitable for main shafts of gas turbine engines.
    Type: Application
    Filed: September 14, 2011
    Publication date: April 5, 2012
    Applicant: ROLLS-ROYCE PLC
    Inventors: Andrew T.W. BARROW, Harshad K.D.H. BHADESHIA, Martin J. RAWSON, Paul O. HILL
  • Patent number: 8147748
    Abstract: A creep-resistant steel is characterized by the following chemical composition (values in % by weight): 9.0 to 12.0 Cr, 0.1 to 0.5 Mn, 2.3 to 3 Ni, 1.5 to 2.0 Mo, 0.1 to 0.4 V, 0.01 to 0.06 Nb, 0.08 to 0.16 C, 0.02 to 0.08 N, 0.004 to 0.012 B, 0.001 to 2 Ta, 0.001 to 0.5 La, 0.0001 to 1 Pd, maximum 0.005 P, maximum 0.005 S, maximum 0.05 Si, maximum 0.005 Sn, the remainder iron and unavoidable impurities. This steel is distinguished, as compared with commercial steels, by a greatly improved creep behavior at temperatures of 550° C. and above. Moreover, it has an improved resistance to embrittlement during long-term aging and comparatively high toughness. The steel is advantageously used as a material for gas turbine rotors which are exposed to high inlet temperatures in order to increase the efficiency of the gas turbine, but is also used for steam turbines.
    Type: Grant
    Filed: September 23, 2009
    Date of Patent: April 3, 2012
    Assignee: ALSTOM Technology Ltd.
    Inventors: Mohamed Nazmy, Markus Staubli, Andreas Kuenzler
  • Patent number: 8143985
    Abstract: Disclosed is a power distribution transformer having a body of the transformer, the body consisting of a coil and an iron core; a tank containing the body of the transformer and an insulation substance which fills an inner space of the tank; and an upper lid of the tank. The tank and/or the upper lid is made of a ferritic stainless steel.
    Type: Grant
    Filed: October 29, 2010
    Date of Patent: March 27, 2012
    Assignees: Hitachi Industrial Equipment Systems Co., Ltd., Nippon Steel & Sumikin Stainless Steel Corp.
    Inventors: Masao Hosokawa, Mitsuaki Kawashima, Kazuyuki Fukui, Kouji Yamashita, Izumi Muto, Eiichiro Ishimaru, Hiroshige Inoue
  • Patent number: 8124007
    Abstract: Compositions for stainless steel weld overlays having enhanced wear resistance are provided by incorporating second phase Titanium Carbide (TiC) and/or Niobium Carbide (NbC) into matrices of various types of stainless steel such as 316L and 420. Preferably, TiC and NbC precipitates are formed in-situ during the weld overlay process while minimizing the amount of Carbon (C) going into solid solution in the matrix of the weld overlay.
    Type: Grant
    Filed: February 16, 2006
    Date of Patent: February 28, 2012
    Assignee: Stoody Company
    Inventors: Ravi Menon, Jack Garry Wallin, Francis Louis LeClaire
  • Patent number: 8118116
    Abstract: An elongated percussive rock drilling element comprises at least one thread portion and a flush channel. At least the thread portion is made of a corrosion resistant steel having a structure with a martensite content greater than about 50 wt-% and less than about 100 wt-%, in which the steel comprises C+N greater than about 0.1 wt-% and less than or equal to about 0.8 wt-% and Cr greater than or equal to about 11 wt-% or Cr greater than or equal to about 5 wt-%, Mo less than or equal to about 5 wt-%, W less than or equal to about 5 wt-%, Cu less than or equal to about 2 wt-%, Mo+W+Cu greater than about 0.5 wt-% or Cr+3.3 (Mo+W)+16N greater than about 10 wt-%. The surface of said at least one thread portion of said corrosion resistant steel is ball blasted.
    Type: Grant
    Filed: July 10, 2008
    Date of Patent: February 21, 2012
    Assignee: Sandvik Intellectual Property AB
    Inventor: Johan Lindèn
  • Publication number: 20120031530
    Abstract: The chemical composition of a stainless steel in accordance with the present invention consists of C: not more than 0.05%, Si: not more than 0.5%, Mn: 0.01 to 0.5%, P: not more than 0.04%, S: not more than 0.01%, Cr: more than 16.0 and not more than 18.0%, Ni: more than 4.0 and not more than 5.6%, Mo: 1.6 to 4.0%, Cu: 1.5 to 3.0%, Al: 0.001 to 0.10%, and N: not more than 0.050%, the balance being Fe and impurities, and satisfies Formulas (1) and (2). Also, the micro-structure thereof contains a martensitic phase and a ferritic phase having a volume ratio of 10 to 40%, and the ferritic phase distribution ratio is higher than 85%. Cr+Cu+Ni+Mo?25.5??(1) ?8?30(C+N)+0.5Mn+Ni+Cu/2+8.2?1.
    Type: Application
    Filed: October 19, 2011
    Publication date: February 9, 2012
    Applicant: SUMITOMO METAL INDUSTRIES, LTD.
    Inventors: Hideki TAKABE, Kunio KONDO, Hisashi AMAYA, Taro OHE, Yohei OTOME
  • Publication number: 20120024430
    Abstract: A stainless steel material having compositions which contain on the basis of percent by mass, C from 0.04 to 0.12%, Ni from 0 (including a case of no addition) to 5.0%, Cr from 12.0 to 17.0%, N from 0.0 to 0.10%, Si from 0.2 to 2.0%, Mn at 2.0% or less, Cu from 0.0 to 2.0%, P at 0.06% or less, S at 0.006% or less, with residue being Fe and unavoidable impurities. Further, a parent phase has any one of a single phase structure of ferrite phase or martensite phase and a diploid phase structure of ferrite phase and martensite phase. An end of the base material is melt-welded. as a joint to form a pipe. The parent phase is provided with carbide uniformly separated at grain boundaries and within grains, with a dissolved amount of C being 0.03% by mass or less.
    Type: Application
    Filed: May 7, 2009
    Publication date: February 2, 2012
    Applicant: NISSHIN STEEL CO., LTD.
    Inventors: Seiichi Isozaki, Yasutoshi Hideshima, Hiroshi Fujimoto, Satoshi Suzuki
  • Patent number: 8092620
    Abstract: An austenitic TRIP steel consisting essentially of, in weight %, 0.14 to 0.18% Al, 2.8 to 3.2% Ti, 23.5 to 23.8% Ni, 3.8 to 4.2% Cr, 1.1 to 1.3% Mo, 0.29 to 0.31% V, 0.01 to 0.015% B, 0.01 to 0.02% C, and balance Fe and incidental impurities exhibits combined high yield strength and high strain hardening leading to improved stretch ductility under both tension and shear dynamic loading conditions.
    Type: Grant
    Filed: July 20, 2009
    Date of Patent: January 10, 2012
    Assignee: Northwestern University
    Inventors: Padmanava Sadhukhan, Gregory B. Olson
  • Publication number: 20110297277
    Abstract: The invention relates to a powder metallurgically manufactured steel with a chemical composition containing, in % by weight: 0.01-2 C, 0.6-10 N, 0.01-3.0 Si, 0.01-10.0 Mn, 16-30 Cr, 0.01-5 Ni, 0.01-5.0 (Mo+W/2), 0.01-9 Co, max. 0.5 S and 0.5-14 (V+Nb/2), where the contents of N on the one hand and of (V+Nb/2) on the other hand are balanced in relation to each other such that the contents of these elements are within an area that is defined by the coordinates A?, 13% G, H, A?, where the coordinates of [N, (V+Nb/2)] are: A?: [0.6,0.5]; B?: [1.6,0.5]; G: [9.8,14.0]; H: [2.6,14.0], and max. 7 of (Ti+Zr+Al), balance essentially only iron and impurities at normal amounts. The steel may be used for tools for injection moulding, compression moulding and extrusion of components of plastics, and cold working.
    Type: Application
    Filed: August 17, 2011
    Publication date: December 8, 2011
    Applicant: UDDEHOLMS AB
    Inventors: Lennart Jönson, Odd Sandberg
  • Publication number: 20110294042
    Abstract: There are provided a ferrite stainless steel for a polymer fuel cell separator having excellent corrosion resistance and interfacial contact resistance under an operating environment of a polymer fuel cell, and a preparation method of the stainless steel. A stainless steel includes C: 0.02 wt % or less, N: 0.02 wt % or less, Si: 0.4 wt % or less, Mn: 0.2 wt % or less, P: 0.04 wt % or less, S: 0.02 wt % or less, Cr: 25.0 to 32.0 wt %, Cu: 0 to 2.0 wt %, Ni: 0.8 wt % or less, Ti: 0.5 wt % or less, Nb: 0.5 wt % or less, waste Fe and inevitably contained elements. A preparation method of the stainless steel having a second passive film formed on a surface thereof includes forming a first passive film on the surface of the stainless steel by bright-annealing or annealing-pickling the stainless steel; removing the first passive film by pickling the stainless steel in a 10 to 20 wt % sulfuric acid solution at a temperature of 50 to 75° C.
    Type: Application
    Filed: December 29, 2009
    Publication date: December 1, 2011
    Inventors: Jonghee Kim, Kihoon Jo, Younghwan Kim, Jeonghe Lee, Yunyong Lee, Jinsuk Kim, Jonghoon Moo Seok
  • Publication number: 20110265920
    Abstract: The present invention provides an alloy-saving type of high purity ferritic stainless steel excellent in corrosion resistance and a method of production of the same. A high purity ferritic stainless steel excellent in corrosion resistance comprised of, by mass %, C: 0.001 to 0.02%, Si: 0.01 to 0.6%, Mn: 0.01 to 0.6%, P: 0.005 to 0.04%, S: 0.0001 to 0.01%, Cr: 13 to 22%, N: 0.001 to 0.02%, Al: 0.005 to 0.05%, Sn: 0.001 to 1%, and a balance of Fe and unavoidable impurities, said steel characterized by satisfying the two relations of the following formula (1) and formula (2) where I(Fe), I(Cr), I(Sn), and I(O) are the X-ray intensities of the Fe oxides, Cr oxides, Sn oxides, and other detected oxides at the steel surface measured by an X-ray photoelectron spectrometer: 0<I(Fe)/I(Cr)<5??formula (1) and 0<I(O)/I(Sn)<3??formula (2) To improve the effect of modification of the coating by addition of Sn, the method comprises annealing at a temperature higher than 800° C.
    Type: Application
    Filed: December 7, 2009
    Publication date: November 3, 2011
    Inventors: Masaharu Hatano, Akihiko Takahashi, Eiichiro Ishimaru, Shigenori Takahata
  • Patent number: 8048239
    Abstract: The present invention provides a ferritic stainless steel sheet superior in shapeability containing, by wt %, C: 0.001 to 0.010%, Si: 0.01 to 1.0%, Mn: 0.01 to 1.0%, P: 0.01 to 0.04%, Cr: 10 to 20%, N: 0.001 to 0.020%, Nb: 0.3 to 1.0%, and Mo: 0.5 to 2.0%, wherein the total precipitates are, by wt %, 0.05 to 0.60%. A method of production of a ferritic stainless steel sheet superior in shapeability comprising producing a cold rolling material in the production process so that the Nb-based precipitates become, by vol %, 0.15% to 0.6% and have a diameter of 0.1 ?m to 1 ?m and/or so that the recrystallized grain size becomes 1 ?m to 40 ?m and the recrystallization rate becomes 10 to 90%, then cold rolling and annealing it at 1010 to 1080° C.
    Type: Grant
    Filed: August 26, 2008
    Date of Patent: November 1, 2011
    Assignee: Nippon Steel & Sumikin Stainless Steel Corporation
    Inventors: Junichi Hamada, Naoto Ono, Yoshiharu Inoue, Ken Kimura
  • Patent number: 8038811
    Abstract: A steel pipe is prepared, which contains, by mass, at most 0.009% C, at most 1.0% Mn, at most 1.0% Si, at most 0.04% P, at most 0.005% S, 0.01 to 0.2% Ti, 0.01 to 0.10% V, 0.001 to 0.1% Al, at most 0.1% N, 4.0 to 8.0% Ni, 9.0 to 15.0% Cr, and 1.5 to 7.0% Mo, the balance being Fe and impurities. The prepared steel pipe is bent into a bend pipe. The bend pipe is quenched at a quenching temperature lower than 950° C. The quenched bend pipe is tempered. Accordingly, the bend pipe in accordance with the present invention has excellent SSC resistance.
    Type: Grant
    Filed: September 23, 2009
    Date of Patent: October 18, 2011
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventor: Takahiro Oka
  • Patent number: 8034197
    Abstract: An ultra-high strength stainless steel alloy with enhanced toughness includes in % by weight: 0 to 0.06% carbon (C); 12.0 to 18% chromium (Cr); 16.5 to 31.0% cobalt (Co); 0 to 8% molybdenum (Mo); 0.5 to 5.0% nickel (Ni); 0 to 0.5% titanium (Ti); 0 to 1.0% niobium (Nb); 0 to 0.5% vanadium (V); 0 to 16% tungsten (W); balance iron (Fe) and incidental deoxidizers and impurities. The heat treating method includes the steps of austenitizing at least once followed by quenching, tempering and sub-zero cooling to obtain no more than about 6-8% retained austenite in the finished alloy.
    Type: Grant
    Filed: June 18, 2008
    Date of Patent: October 11, 2011
    Assignee: Carnegie Mellon University
    Inventor: Warren M. Garrison, Jr.
  • Patent number: 8034198
    Abstract: The present invention relates to an austenitic stainless steel tube for boiler, used for superheater or reheater in thermal power plant, giving excellent resistance to high temperature steam oxidation, in particular to an austenitic stainless steel tube containing 16 to 20% Cr by weight, and being cold-worked at the inner surface of the tube. The Cr concentration in the vicinity of the inner surface of the steel tube is 14% by weight or larger, and the hardness at 100 ?m depth from the inner surface of the steel tube is 1.5 times or larger the average hardness of the mother material or is HV 300 or larger.
    Type: Grant
    Filed: August 23, 2006
    Date of Patent: October 11, 2011
    Assignee: NKK Tubes
    Inventors: Yusuke Minami, Hitoshi Iijima, Motohisa Yoshida, Toshihiko Fukui, Tatsuo Ono
  • Patent number: 8025839
    Abstract: The invention relates to a powder metallurgically manufactured steel with a chemical composition containing, in % by weight: 0.01-2 C, 0.6-10 N, 0.01-3.0 Si, 0.01-10.0 Mn, 16-30 Cr, 0.01-5 Ni, 0.01-5.0 (Mo+W/2), 0.01-9 Co, max. 0.5 S and 0.5-14 (V+Nb/2), where the contents of N on the one hand and of (V+Nb/2) on the other hand are balanced in relation to each other such that the contents of these elements are within an area that is defined by the coordinates A?, B?, G, H, A?, where the coordinates of [N, (V+Nb/2)] are: A: [0.6,0.5]; B?: [1.6,0.5]; G: [9.8,14.0]; H: [2.6,14.0], and max. 7 of (Ti+Zr+Al), balance essentially only iron and impurities at normal amounts. The steel is intended to be used in the manufacturing of tools for injection moulding, compression moulding and extrusion of components of plastics, and for tools for cold working, which are exposed to corrosion.
    Type: Grant
    Filed: August 24, 2006
    Date of Patent: September 27, 2011
    Assignee: Uddeholms AB
    Inventors: Lennart Jönson, Odd Sandberg
  • Patent number: 8017071
    Abstract: A corrosion resistant, martensitic steel alloy having very good cold formability is described. The alloy has the following weight percent composition. Carbon 0.10-0.40 Manganese 0.01-2.0? Silicon ?2.0 max. Phosphorus ?0.2 max. Sulfur 0.030 max.? Chromium 10-15 Nickel ?0.5 max. Molybdenum 0.75-4.0? Nitrogen 0.02-0.15 Copper 1.5-4.0 Titanium 0.01 max. Aluminum 0.01 max. Niobium + Tantalum 0.10 max. Vanadium 0.20 max. Zirconium less than 0.001 Calcium less than 0.001 The balance of the alloy is essentially iron. Nickel and copper are balanced in the alloy such that the ratio Ni/Cu is less than 0.2. A second embodiment of the alloy contains at least about 0.005% sulfur, selenium, or a combination thereof to provide good machinability.
    Type: Grant
    Filed: August 26, 2009
    Date of Patent: September 13, 2011
    Assignee: CRS Holdings, Inc.
    Inventor: John H. Magee, Jr.
  • Patent number: 8012272
    Abstract: The present invention provides a tool steel containing, by mass percent, 0.55 to 0.85% of C, 0.20 to 2.50% of Si, 0.30 to 1.20% of Mn, 0.50% or less of Cu, 0.01 to 0.50% of Ni, 6.00 to 9.00% of Cr, 0.1 to 2.00% of Mo+0.5 W, and 0.01 to 0.40% of V, with the balance of Fe and inevitable impurities, in which, when an area rate of a coarse carbide having a circle equivalent diameter of 2 ?m or more in a cross section parallel to a forging direction is represented by L(%) and an area rate of the coarse carbide in a cross section perpendicular to the forging direction is represented by T(%), the area rate L is 0.001% or more, the area rate T is 0.001% or more, and the ratio L/T is within a range from 0.90 to 3.00. The tool steel of the invention exhibits an isotropic size change in quenching and tempering.
    Type: Grant
    Filed: October 30, 2008
    Date of Patent: September 6, 2011
    Assignee: Daido Tokushuko Kabushiki Kaisha
    Inventor: Takayuki Shimizu
  • Patent number: 8007715
    Abstract: A steel has the following chemical composition (amounts in % by weight): 0.05-0.14 C, 8-13 Cr, 1-2.6 Ni, 0.5-1.9 Mo, 0.5-1.5 Mn, 0.15-0.5 Si, 0.2-0.4 V, 0-0.04 B, 2.1-4.0 Re, 0-0.07 Ta, 0-60 ppm Pd, remainder Fe and unavoidable impurities. The steel can be used effectively as a welding additive material and has outstanding properties at very high temperatures, in particular a good creep rupture strength/resistance and a good oxidation resistance.
    Type: Grant
    Filed: February 12, 2010
    Date of Patent: August 30, 2011
    Assignee: ALSTOM Technology Ltd.
    Inventors: Mohamed Nazmy, Paul Claus Gerdes, Andreas Kuenzler
  • Patent number: 8007602
    Abstract: Spring element, in particular spring rail for wipers, in particular of motor vehicles, with a low tendency to vibrate or a high attenuation, made from a ferritic chromium steel comprising 0.03 to 0.12% of carbon, 0.2 to 0.9% of silicon, 0.3 to 1% of manganese, 13 to 20% of chromium, 0.1 to 2.0% of molybdenum, 0.05 to 1.0% of copper, 0.02 to 0.05% of nitrogen, less than 0.01% of titanium, 0.01 to 0.10% of niobium and 0.02 to 0.25% of vanadium, remainder iron.
    Type: Grant
    Filed: February 4, 2010
    Date of Patent: August 30, 2011
    Assignee: Stahlwerk Ergste Westig GmbH
    Inventors: Oskar Pacher, Gisbert Kloss-Ulitzka, Victor Castro
  • Patent number: 7998238
    Abstract: A sintered sliding member comprises a back metal (21a) and a ferrous sintered sliding body (20) which is sintering-bonded to the back metal (21a). The ferrous sintered sliding body (20) has martensite phase having a solid soluble carbon concentration of 0.15 to 0.5 wt % and contains carbide in a content of 5 to 50% by volume. The sintered sliding member is excellent in abrasion resistance, seizing resistance and heat crack resistance.
    Type: Grant
    Filed: July 30, 2004
    Date of Patent: August 16, 2011
    Assignee: Komatsu Ltd.
    Inventors: Takemori Takayama, Tetsuo Ohnishi, Kazuo Okamura
  • Patent number: 7985372
    Abstract: A ferritic stainless steel sheet for use in raw material pipes for forming bellows pipes has excellent formability. More specifically, the ferritic stainless steel sheet contains 10 % to 25 % by mass of Cr and has a yield stress in the range of 300 to 450 MPa and the product of the yield stress and the uniform elongation properties of at least 5200 (MPa·%). Preferably, the ferritic stainless steel sheet for use in raw material pipes for forming bellows pipes has an average crystal grain size D of 35 ?m or less or a surface roughness of 0.40 ?m or less as determined by Ra.
    Type: Grant
    Filed: May 29, 2006
    Date of Patent: July 26, 2011
    Assignee: JFE Steel Corporation
    Inventors: Yoshihiro Ozaki, Yasushi Kato, Takaaki Iguchi
  • Publication number: 20110162764
    Abstract: High-Cr ferritic/martensitic steels having an improved tensile strength and creep resistance are provided, which includes 0.04˜0.13 weight % of carbon, 0.03˜0.07 weight % of silicon, 0.40˜0.50 weight % of manganese, 0.40˜0.50 weight % of nickel, 8.5˜9.5 weight % of chromium, 0.45˜0.55 weight % of molybdenum, 0.10˜0.25 weight % of vanadium, 0.02˜0.10 weight % of tantalum, 0.15˜0.25 weight % of niobium, 1.5˜3.0 weight % of tungsten, 0.05˜0.12 weight % of nitrogen, 0.004˜0.008 weight % of boron, and optionally, 0.002˜0.010 weight % of phosphorus or 0.01˜0.08 weight % of zirconium, and iron balance. By regulating the contents of alloying elements such as niobium, tantalum, tungsten, nitrogen, boron, zirconium, carbon, the high-Cr ferritic/martensitic steels with superior tensile strength and creep resistance are provided, and can be effectively used as an in-core structural material for Generation IV sodium-cooled fast reactor (SFR) which is used under high temperature and high irradiation conditions.
    Type: Application
    Filed: January 5, 2011
    Publication date: July 7, 2011
    Applicants: KOREA ATOMIC ENERGY RESEARCH INSTITUTE, KOREA HYDRO AND NUCLEAR POWER CO., LTD.
    Inventors: Sung Ho Kim, Jong Hyuk Baek, Tae Kyu Kim, Woo Gon Kim, Jun Hwan Kim, Chang Hee Han, Chan Bock Lee, Yeong-Il Kim, Dohee Hahn
  • Patent number: 7967922
    Abstract: A ferrous abrasion resistant sliding material capable of improving seizing resistance, abrasion resistance and heat crack resistance is provided. The ferrous abrasion resistant sliding material has a martensite parent phase which forms a solid solution with carbon of 0.15 to 0.5 wt %, and the martensite parent phase contains one or more types of each special carbide of Cr, Mo, W and V dispersed therein in a total content of 10 to 50% by volume.
    Type: Grant
    Filed: December 30, 2009
    Date of Patent: June 28, 2011
    Assignee: Komatsu Ltd.
    Inventor: Takemori Takayama
  • Publication number: 20110132501
    Abstract: A martensitic stainless steel seamless tube for oil country tubular goods includes a yield strength of 95 ksi or more and low-temperature toughness in which a fracture transition temperature vTrs in a Charpy impact test is ?40° C. or below, wherein the seamless tube has a composition comprising, by mass %, 0.020% or less C, 10 to 14% Cr, 3% or less Ni, 0.03 to 0.2% Nb, 0.05% or less N, and Fe and unavoidable impurities as a balance, and has a structure where a precipitated Nb quantity is 0.020% or more in terms of Nb.
    Type: Application
    Filed: December 24, 2008
    Publication date: June 9, 2011
    Applicant: JFE STEEL CORPORATION
    Inventors: Kenichiro Eguchi, Yukio Miyata, Mitsuo Kimura
  • Publication number: 20110132499
    Abstract: The ferrite system heat-resistant cast steel and the exhaust system component are provided, which are inexpensive and are able to improve the reliability by largely improving the toughness under normal temperature and thermal fatigue performance. The ferrite system heat-resistant cast steel includes composition structure comprised, percent by mass, of 0.1% to 0.4% carbon, 0.5% to 2.0% silicon, 0.2% to 1.2% manganese, 0.3% or less phosphorus, 0.01% to 0.4% sulfur, 14.0% to 21.0% chrome, 0.05% to 0.6% niobium, 0.01% to 0.8% aluminum, 0.15% to 2.3% nickel, residual iron and inevitable impurities.
    Type: Application
    Filed: February 8, 2010
    Publication date: June 9, 2011
    Inventors: Daisuke Yamanaka, Zhong-zhi Zhang
  • Publication number: 20110114232
    Abstract: The present invention aims at providing: a method for manufacturing such a kind of gasket-oriented steel plate excellent in elasticity and formability, in a manner to allow for reduction of a breaking elongation of the steel plate to thereby improve a formability (punchability) thereof while improving a proof stress of the steel plate against a repeated stress from a discharge valve to thereby maintain a higher elasticity of the steel plate; and a gasket able to withstand the repeated stress from the discharge valve. The manufacturing method of a gasket-oriented steel plate of the present invention comprises the steps of: annealing a starting steel material having a composition of: Mn less than 0.5%, Ni less than 2.0%, and Cr less than 12.0%; and subsequently temper rolling the annealed starting steel material at a rolling reduction ratio of 10% or more; and the gasket of the present invention is formed by adopting a gasket-oriented steel plate obtained by the above manufacturing method.
    Type: Application
    Filed: December 2, 2009
    Publication date: May 19, 2011
    Applicant: NOK Corporation
    Inventors: Takashi Nakao, Nobuaki Tanaka
  • Publication number: 20110097234
    Abstract: The present invention provides a lean duplex stainless steel able to suppress the drop in corrosion resistance and toughness of a weld heat affected zone and is characterized by containing, by mass %, C: 0.06% or less, Si: 0.1 to 1.5%, Mn: 2.0 to 4.0%, P: 0.05% or less, S: 0.005% or less, Cr: 19.0 to 23.0%, Ni: 1.0 to 4.0%, Mo: 1.0% or less, Cu: 0.1 to 3.0%, V: 0.05 to 0.5%, Al: 0.003 to 0.050%, 0: 0.007% or less, N: 0.10 to 0.25%, and Ti: 0.05% or less, having a balance of Fe and unavoidable impurities, having an Md30 value expressed by formula (1) of 80 or less, having an Ni-bal expressed by formula (2) of ?8 to ?4, having a relationship between the Ni-bal and the N content satisfying formula (3), having an austenite phase area percentage of 40 to 70%, and having a 2×Ni+Cu of 3.5 or more: Md30=551?462×(C+N)?9.2×Si?8.1×Mn?29×(Ni+Cu)?13.7×Cr?18.5×Mo?68×Nb ??(1) Ni-bal=(Ni+0.5Mn+0.5Cu+30C+30N)?1.1(Cr+1.5Si+Mo+W)+8.2 ??(2) N(%)?0.37+0.
    Type: Application
    Filed: March 26, 2009
    Publication date: April 28, 2011
    Inventors: Yuusuke Oikawa, Hiroshi Urashima, Shinji Tsuge, Hiroshige Inoue, Ryo Matsuhashi
  • Publication number: 20110086726
    Abstract: An iron-based alloy for a golf club head includes: chromium in an amount ranging from 16.3 to 17.2 wt %; nickel in an amount ranging from 5.8 to 6.5 wt %; nitrogen in an amount ranging from 0.10 to 0.20 wt %; carbon in an amount ranging from 0.01 to 0.12 wt %; silicon in an amount ranging from 0.3 to 1.2 wt %; manganese in an amount ranging from 0.3 to 1.2 wt %; and a balance of iron and impurities, based on a total weight of the iron-based alloy. The alloy has a duplex-phase microstructure including a martensite phase and 10 to 30 percent austenite phase, and has a tensile strength greater than 120 Ksi and an elongation greater than 35%.
    Type: Application
    Filed: October 13, 2009
    Publication date: April 14, 2011
    Applicant: O-TA PRECISION INDUSTRY CO., LTD.
    Inventor: Chih-Yeh Chao
  • Patent number: 7922836
    Abstract: A ferrous abrasion resistant sliding material capable of improving seizing resistance, abrasion resistance and heat crack resistance is provided. The ferrous abrasion resistant sliding material has a martensite parent phase which forms a solid solution with carbon of 0.15 to 0.5 wt %, and the martensite parent phase contains one or more types of each special carbide of Cr, Mo, W and V dispersed therein in a total content of 10 to 50% by volume.
    Type: Grant
    Filed: November 30, 2009
    Date of Patent: April 12, 2011
    Assignee: Komatsu Ltd.
    Inventor: Takemori Takayama
  • Patent number: 7914732
    Abstract: The present invention provides: a ferritic stainless steel cast iron including: Fe as a main component; C: 0.20 to 0.40 mass %; Si: 1.00 to 3.00 mass %; Mn: 0.30 to 3.00 mass %; Cr: 12.0 to 30.0 mass %; and one of Nb and V, or both of Nb and V in total: 1.0 to 5.0 mass %, the ferritic stainless steel cast iron satisfying the following formula (1): 1400?1562.3?{133WC+14WSi+5WMn+10(WNb+WV)}?1480??(1) wherein, WC (mass %), WSi (mass %), WMn (mass %), WCr (mass %), WNb (mass %), WV (mass %) and WCu (mass %) are contents of C, Si, Mn, Cr, Nb, V and Cu, respectively; a process for producing a cast part from the ferritic cast steel; and the cast part.
    Type: Grant
    Filed: February 23, 2007
    Date of Patent: March 29, 2011
    Assignee: Daido Tokushuko Kabushiki Kaisha
    Inventors: Hiroyuki Takabayashi, Shigeki Ueta, Tetsuya Shimizu, Toshiharu Noda
  • Publication number: 20110061776
    Abstract: The invention relates to a hot-rolled sheet made of austenitic stainless steel, the chemical composition of which comprises, the contents being expressed by weight: 0.015%?C?0.030%, 0.5%?Mn?2%, Si?2%, 16.5%?Cr?18%, 6%?Ni?7%, S?0.015%, P?0.045%, Al?0.050%, 0.15%?Nb?0.31%, 0.12%?N?0.16%, the Nb and N contents being such that: Nb/8+0.1%?N?Nb/8+0.12%, optionally: Mo?0.6%, 0.0005%?B?0.0025%, the balance of the composition consisting of iron and inevitable impurities resulting from the smelting.
    Type: Application
    Filed: March 3, 2009
    Publication date: March 17, 2011
    Applicant: ARCELORMITTAL-STAINLESS FRANCE
    Inventors: Jean-Christophe Glez, Valerie Kostoj
  • Publication number: 20110061777
    Abstract: A ferritic stainless steel sheet and a method for manufacturing the ferritic stainless steel sheet include a composition which contains 0.0030 to 0.012 mass percent of C, 0.13 mass percent or less of Si, 0.25 mass percent or less of Mn, 0.04 mass percent or less of P, 0.005 mass percent or less of S, 0.06 mass percent or less of Al, 0.0030 to 0.012 mass percent of N, 20.5 to 23.5 mass percent of Cr, 0.3 to 0.6 mass percent of Cu, 0.5 mass percent or less of Ni, 0.3 to 0.5 mass percent of Nb, 0.05 to 0.15 mass percent of Ti, and the balance being Fe and inevitable impurities is hot-rolled at a finishing temperature of 900° C. or more and at a coiling temperature of 400 to 550° C., softening annealing is performed on an obtained hot-rolled steel sheet, picking is further performed, and cold rolling is subsequently performed.
    Type: Application
    Filed: June 18, 2008
    Publication date: March 17, 2011
    Applicant: JFE STEEL CORPORATION
    Inventors: Tomohiro Ishii, Yoshimasa Funakawa, Shuji Okada, Masayuki Ohta
  • Patent number: 7892366
    Abstract: The present invention relates to a stainless steel alloy, more specifically a duplex stainless steel alloy with a ferritic-austenitic matrix and high corrosion resistance in combination with good structure stability, specifically a duplex stainless steel with a ferrite content of 40-65% and a well balanced analysis and with a combination of high corrosion resistance and good mechanical properties, such as high ultimate strength and good ductility which is especially suitable for use in applications in oil and gas explorations such as wire, especially as reinforced wire in wireline applications. These purposes are achieved according to the invention by a duplex stainless steel alloy that contains (in wt %): C 0-0.03%; Si up to max 0.5%; Mn 0-3.0%; Cr 24.0-30.0%; Ni 4.9-10.0%; Mo 3.0-5.0%; N 0.28-0.5%; S up to max. 0.010%; Co 0-3.5%; W 0-3.0%; Cu 0-2%; Ru 0-0.3%; Al 0-0.03; Ca 0-0.010%; the balance being Fe and unavoidable impurities.
    Type: Grant
    Filed: February 19, 2004
    Date of Patent: February 22, 2011
    Assignee: Sandvik Intellectual Property AB
    Inventor: Anders Lindh
  • Publication number: 20110030851
    Abstract: A material for brake discs has temper softening resistance sufficient to maintain a hardness of HRC 31 or more after tempering at 700° C. for one hour. The low-carbon martensitic chromium-containing steel contains 0.02% to 0.10% of carbon and 0.02% to 0.10% of nitrogen, the total content of carbon and nitrogen being 0.08% to 0.16%; 0.5% or less of silicon; 0.1% or less of aluminum; 0.3% to 3.0% of manganese; 10.5% to 13.5% of chromium; 0.05% to 0.60% of niobium and 0.15% to 0.80% of vanadium, the total content of niobium and vanadium being 0.25% to 0.95%; 0.02% to 2.0% of nickel; and 1.5% or less of copper, and has an Fp value (=?230C+5Si?5Mn?6Cu+10Cr?12Ni+32Nb+22V+12Mo+8W+10Ta+40Al?220N) of 80.0 to 96.0, a hardness after quenching of HRC 31 to 40, and a hardness after tempering at 700° C. for one hour of HRC 31 or more.
    Type: Application
    Filed: April 23, 2009
    Publication date: February 10, 2011
    Applicant: JFE STEEL CORPORATION
    Inventors: Katsuhisa Yamauchi, Yasushi Kato, Takumi Ujiro, Takako Yamashita
  • Publication number: 20110024003
    Abstract: A quenched and tempered high strength, corrosion resistant steel suitable for aircraft landing gears and structures, having a unique combination of mechanical and corrosion resistant properties: ultimate tensile strength of 295 to 305 ksi, yield strength of 225 to 235 ksi; elongation of 12 to 13.5%, reduction of area of 34 to 36%, Charpy v-notch impact toughness energy of about 14 to 16 ft-lb, fracture toughness of 55 to 60 ksiVin, and corrosion resistance in salt spray test.
    Type: Application
    Filed: July 31, 2010
    Publication date: February 3, 2011
    Inventor: Gregory Vartanov
  • Patent number: 7879159
    Abstract: A precipitation-hardened stainless maraging steel which exhibits a combination of strength, toughness, and corrosion resistance comprises by weight about: 8 to 15% chromium (Cr), 2 to 15% cobalt (Co), 7 to 14% nickel (Ni), and up to about 0.7% aluminum (Al), less than about 0.4% copper (Cu), 0.5 to 2.6% molybdenum (Mo), 0.4 to less than about 0.75% titanium (Ti), up to about 0.5% tungsten (W), and up to about 120 wppm carbon (C), the balance essentially iron (Fe) and incidental elements and impurities, characterized in that the alloy has predominantly lath martensite microstructure essentially without topologically close packed intermetallic phases and strengthened primarily by a dispersion of intermetallic particles primarily of the eta-Ni3Ti phase and wherein the titanium and carbon (Ti) and (C) levels are controlled such that C can be dissolved during a homogenization step and subsequently precipitated during forging to provide a grain-pinnning dispersion.
    Type: Grant
    Filed: January 25, 2006
    Date of Patent: February 1, 2011
    Assignee: QuesTek Innovations, LLC
    Inventors: James Wright, Jin-Won Jung
  • Publication number: 20110017355
    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 ? ferrite.
    Type: Application
    Filed: October 8, 2010
    Publication date: January 27, 2011
    Applicants: BABCOCK-HITACHI KABUSHIKI KAISHA
    Inventors: Takashi SATO, Kohji TAMURA, Toshio FUJITA
  • Publication number: 20110000589
    Abstract: This ferrite-austenite stainless steel sheet includes: in terms of mass %, C: 0.1% or less; Cr: 17 to 25%; Si: 1% or less; Mn: 3.7% or less; Ni: 0.6 to 3%; Cu: 0.1 to 3%; and N: 0.06% or more and less than 0.15%, with the remainder being Fe and inevitable impurities, wherein the steel sheet has a two-phase structure consisting of a ferrite phase and an austenite phase, a volume fraction of the austenite phase is in a range of 15 to 70%, and in a sheet plane (ND) of a center of a sheet thickness, grains of the ferrite phase having a crystal orientation satisfying ND//{111}±10° and grains of the ferrite phase having a crystal orientation satisfying ND//{101}±10° are present in a total content of 10% by area or more.
    Type: Application
    Filed: January 30, 2009
    Publication date: January 6, 2011
    Applicant: Nippon Steel & Sumikin Stainless Steel Corporation
    Inventors: Masaharu Hatano, Akihiko Takahashi, Eiichiro Ishimaru, Ken Kimura
  • Patent number: 7862666
    Abstract: A highly corrosion resistant high strength stainless steel pipe for linepipe, having a composition containing about 0.001 to about 0.015% C, about 0.01 to about 0.5% Si, about 0.1 to about 1.8% Mn, about 0.03% or less P, about 0.005% or less S, about 15 to about 18% Cr, about 0.5% or more and less than about 5.5% Ni, about 0.5 to about 3.5% Mo, about 0.02 to about 0.2% V, about 0.001 to about 0.015% N, and about 0.006% or less O, by mass, so as to satisfy (Cr+0.65 Ni +0.6Mo+0.55Cu?20C?18.5), (Cr+Mo+0.3Si?43.5C?0.4Mn?Ni?0.3Cu?9 N?11.5) and (C+N?0.025). Preferably quenching and tempering treatment is applied to the pipe. The composition may further contain about 0.002 to about 0.05% Al, and may further contain one or more of Nb, Ti, Zr, B, and W, and/or Cu and Ca. The microstructure preferably contains martensite, ferrite, and residual ?.
    Type: Grant
    Filed: October 22, 2004
    Date of Patent: January 4, 2011
    Assignee: JFE Steel Corporation
    Inventors: Mitsuo Kimura, Takanori Tamari, Yoshio Yamazaki, Ryosuke Mochizuki
  • Publication number: 20100308505
    Abstract: A mold plate having a mold cavity configured for plastic injection molding one or more articles such as a panel or frame of an electronic display screen such as a flat screen TV is formed from a low carbon martensitic stainless steel alloy comprising: about 0.05%-0.07% by weight C, about 1.15%-1.45% by weight Mn, a maximum of 0.025% by weight P, a maximum of 0.008% by weight S, about 0.3%-0.6% by weight Si, about 12.15%-12.65% by weight Cr, about 0%-0.5% by weight Ni, about 0.45%-0.65% by weight Cu, about 0.02%-0.08% by weight V, about 0.04%-0.08% by weight N, with the balance being Fe with trace amounts of ordinarily present elements.
    Type: Application
    Filed: June 5, 2009
    Publication date: December 9, 2010
    Applicant: EDRO Specialty Steels, Inc.
    Inventors: Kristopher D. Welch, Robert J. Friedrich, Eric D. Henn, Michael A. Guscott
  • Patent number: 7842141
    Abstract: A steel composition contains: 0.05% or less of C; 0.5% or less of Si; 0.20% to 1.80% of Mn; 0.03% or less of P; 0.005% or less of S; 14.0% to 18.0% of Cr; 5.0% to 8.0% of Ni; 1.5% to 3.5% of Mo; 0.5% to 3.5% of Cu; 0.05% or less of Al; 0.20% or less of V; 0.01% to 0.15% of N; and 0.006% or less of O on a mass basis, and satisfies the following expressions: Cr+0.65Ni+0.6Mo+0.55Cu?20C?18.5 and Cr+Mo+0.3Si?43.5C?0.4Mn?Ni?0.3Cu?9N?11 (where Cr, Ni, Mo, Cu, C, Si, Mn, and N represent their respective contents (mass %)). After such a steel pipe material is formed into a steel pipe, the steel pipe is quenched by cooling after heating to a temperature of the AC3 transformation point or more and tempered at a temperature of the AC1 transformation point or less.
    Type: Grant
    Filed: April 2, 2009
    Date of Patent: November 30, 2010
    Assignee: JFE Steel Corporation
    Inventors: Mitsuo Kimura, Takanori Tamari, Takaaki Toyooka
  • Publication number: 20100294402
    Abstract: This stainless steel sheet includes, in terms of mass %, C: 0.001 to 0.1%, N: 0.01 to 0.15%, Si: 0.01 to 2%, Mn: 0.1 to 10%, P: 0.05% or less, S: 0.01% or less, Ni: 0.5 to 5%, Cr: 10 to 25%, and Cu: 0.5 to 5%, with a remainder being Fe and unavoidable impurities, and contains a ferrite phase as a main phase and 10% or more of an austenite phase, wherein a work-hardening rate in a strain range of up to 30% is 1000 MPa or more which is measured by a static tensile testing and a difference between static and dynamic stresses which occur when 10% of deformation is caused is 150 MPa or more. This method for producing a stainless steel includes annealing a cold-rolled steel sheet under conditions where a holding temperature is set to be in a range of 950 to 1150° C. and a cooling rate until 400° C. is set to be in a range of 3° C./sec or higher.
    Type: Application
    Filed: January 22, 2009
    Publication date: November 25, 2010
    Inventors: Junichi Hamada, Haruhiko Kajimura, Eiichiro Ishimaru
  • Publication number: 20100276038
    Abstract: Martensitic stainless steel, characterised in that it comprises, in percentages by weight: 0.22%?C?0.32% 0.05%?N?0.15%, with 0.33%?C+N?0.43% 10%?Cr?12.4% 0.10%?V?0.40% 0.10%?Mo?1.0% trace levels?Ni?1.0% trace levels?Mn?1.0% trace levels?Si?1.0% trace levels?W?1.0% trace levels?Co?1.0% trace levels?Cu?1.0% trace levels?Ti?0.010% trace levels?Nb?0.050% trace levels?Al?0.050% trace levels?S?0.020% trace levels?O?0.0040% trace levels?P?0.03% trace levels?B?0.0050% trace levels?Ca?0.020% trace levels?Se?0.010% trace levels?La?0.040% trace levels?Ce?0.040% the remainder being iron and impurities resulting from the production operation. Method for producing a component from this steel, and component obtained in this manner, such as a mould element for the production of articles of plastics material.
    Type: Application
    Filed: August 25, 2008
    Publication date: November 4, 2010
    Applicant: AUBERT & DUVAL
    Inventor: Andre Francis Grellier
  • Patent number: 7819991
    Abstract: A ferritic stainless steel sheet for forming a raw material pipe for bellows pipe is excellent in formability and high-temperature properties (high-temperature salt corrosion resistance and high-temperature fatigue properties). Specifically, the ferritic stainless steel sheet for forming a raw material pipe for bellows pipe contains 0.015% by mass or less of C, 1.0% by mass or less of Si, 1.0% by mass or less of Mn, 0.04% by mass or less of P, 0.010% by mass or less of S, 11% to 19% by mass of Cr, 0.015% by mass or less of N, 0.15% by mass or less of Al, 1.25% to 2.5% by mass of Mo, 0.3% to 0.7% by mass of Nb, 0.0003% to 0.003% by mass of B, and the balance being Fe and incidental impurities. In the ferritic stainless steel sheet for forming a raw material pipe for bellows pipe, preferably, the average crystal grain diameter D of the steel sheet is 35 ?m or less, and alternatively, the surface roughness Ra of the steel sheet is 0.40 ?m or less.
    Type: Grant
    Filed: May 29, 2006
    Date of Patent: October 26, 2010
    Assignee: JFE Steel Corporation
    Inventors: Yasushi Kato, Yoshihiro Ozaki, Osamu Furukimi, Norimasa Hirata, Takumi Ujiro
  • Patent number: 7806993
    Abstract: The present invention provides a ferritic stainless steel that has excellent strength at high temperature, oxidation resistance at high temperature, and salt corrosion resistance at high temperature and that can be used under high temperatures exceeding 900° C., and a method of producing the same. Specifically, the composition thereof is adjusted, on a % by mass basis, so as to include C: 0.02% or less; Si: 2.0% or less; Mn: 2.0% or less; Cr: from 12.0 to 40.0%; Mo: from 1.0 to 5.0%; W: more than 2.0% and 5.0% or less; wherein the total content of Mo and W: (Mo+W)?4.3%, Nb: from 5 (C+N) to 1.0%, N: 0.02% or less, and Fe and inevitable impurities as residual.
    Type: Grant
    Filed: June 2, 2003
    Date of Patent: October 5, 2010
    Assignee: JFE Steel Corporation
    Inventors: Atsushi Miyazaki, Kenji Takao, Osamu Furukimi