Ageing, Solution Treating (i.e., For Hardening), Precipitation Strengthening Or Precipitation Hardening Patents (Class 148/607)
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Publication number: 20040084116Abstract: A method of manufacturing a ferritic stainless steel sheet having good workability with less anisotropy. The steps include providing a ferritic stainless steel comprising C up to about 0.03 mass %, N up to about 0.03 mass %, Si up to about 2.0 mass %, Mn up to about 2.0 mass %, Ni up to about 0.6 mass %, Cr about 9-35 mass %, Nb about 0.15-0.80 mass % and the balance being Fe except inevitable impurities; precipitation-heating said stainless steel at a temperature in a range of 700-850° C. for a time period not longer than 25 hours; and finish-annealing said stainless steel at a temperature in a range of 900-1100° C. for a time period not longer than 1 minute.Type: ApplicationFiled: October 28, 2003Publication date: May 6, 2004Applicant: Nisshin Steel Co., Ltd.Inventors: Manabu Oku, Yoshitomo Fujimura, Yoshiaki Hori, Toshirou Nagoya, Yasutoshi Kunitake, Takeo Tomita
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Publication number: 20040050462Abstract: A ferritic stainless steel having improved high temperature mechanical properties includes greater than 25 weight percent chromium, 0.75 up to 1.5 weight percent molybdenum, up to 0.Type: ApplicationFiled: June 24, 2003Publication date: March 18, 2004Inventor: John F. Grubb
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Patent number: 6641780Abstract: A ferritic stainless steel having improved high temperature mechanical properties includes greater than 25 weight percent chromium, 0.75 up to 1.5 weight percent molybdenum, up to 0.05 weight percent carbon, and at least one of niobium, titanium, and tantalum, wherein the sum of the weight percentages of niobium, titanium, and tantalum satisfies the following equation: 0.4≦(%Nb+%Ti+½(%Ta))≦1. The coefficient: of thermal expansion of the ferritic stainless steel is within 25 percent of the CTE of stabilized zirconia between 20° C. (68° F.) and 1000° C. (1832° F.), and the steel exhibits at least one creep property selected from creep rupture strength of at least 1000 psi at 900° C. (1,652° F.), time to 1% creep strain of at least 100 hours at 900° C. (1652° F.) under load of 1000 psi, and time to 2% creep strain of at least 200 hours at 900° C. (1652° F.) Under load of 1000 psi.Type: GrantFiled: November 30, 2001Date of Patent: November 4, 2003Assignee: ATI Properties Inc.Inventor: John F. Grubb
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Publication number: 20030188812Abstract: A ferritic heat-resistant steel, which exhibits excellent creep characteristics even at a high temperature exceeding 600° C., comprises, on the basis of percent by weight, 1.0 to 13% of chromium, 0.1 to 8.0% of cobalt, 0.01 to 0.20% of nitrogen, 3.0% or less of nickel, 0.01 to 0.50% of one or more of elements selected from a group consisting of vanadium, niobium, tantalum, titanium, hafnium, and zirconium that are MX type precipitate forming elements, and 0.01% or less of carbon and a balance being substantially iron and inevitable impurities, wherein the MX type precipitates precipitate on grain boundaries and in entire grains and the grain boundary existing ratio of an M23C6 type precipitate precipitating on the grain boundaries is 50% or less.Type: ApplicationFiled: June 4, 2003Publication date: October 9, 2003Inventors: Masaki Taneike, Fujio Abe
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Patent number: 6623569Abstract: A duplex stainless steel includes less than, in weight percent, 3 percent nickel and 1.5 percent molybdenum. In one embodiment, the duplex stainless steel includes, in weight percent, up to 0.06 percent carbon; 15 to 25 percent chromium; 1 to less than 2.5 percent nickel; greater than 2 percent up to 3.75 percent manganese; greater than 0.12 up to 0.35 percent nitrogen; up to 2 percent silicon; up to 1.5 percent molybdenum; up to 0.5 percent copper; up to 0.2 percent cobalt; up to 0.05 percent phosphorous; up to 0.005 percent sulfur; 0.001 to 0.0035 percent boron; iron and incidental impurities. The duplex stainless steel provided may be provided in the form of an article of manufacture, such as strip, bar, plate, sheet, casting, tubing or piping. A method for making the duplex stainless steel of the invention also is disclosed.Type: GrantFiled: September 10, 2002Date of Patent: September 23, 2003Assignee: ATI Properties, Inc.Inventors: David S. Bergstrom, John J. Dunn, John F. Grubb, William A. Pratt
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Patent number: 6589363Abstract: A stainless steel hydraulic component and method for making same hard turns a pre-heat treated stainless steel material, preferably a 400 series stainless steel material, provided in bar stock form in a single machining loading. Stainless steel hydraulic valve components made therefrom have shown improved leakage rate performance with the performance being fairly constant over a period of time for providing a longer functional life for the hydraulic valve component.Type: GrantFiled: December 13, 2000Date of Patent: July 8, 2003Assignee: Eaton CorporationInventors: Daniel P. Rohde, John N. Tackes
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Publication number: 20030116239Abstract: This invention relates to a method of manufacturing an improved ferritic or martensitic alloy based on iron and chromium strengthened by a dispersion of oxides, commonly called an Oxide Dispersion Strengthened or ODS alloy, and, more particularly to a method of manufacturing a ferritic or martensitic ODS alloy with large grains based on iron and chromium which has a single phase ferritic or martensitic matrix having an isotropic microstructure and a grain size that is sufficient to guarantee mechanical strength compatible with a use of this alloy at high temperature and/or under neutron irradiation.Type: ApplicationFiled: September 25, 2002Publication date: June 26, 2003Inventors: Veronique Lambard, Ana Alamo, Jean-Louis Seran
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Patent number: 6576068Abstract: A method for producing a stainless steel with improved corrosion resistance includes homogenizing at least a portion of an article of a stainless steel including chromium, nickel, and molybdenum and having a PREN of at least 50, as calculated by the equation: PREN=Cr+(3.3×Mo)+(30×N), where Cr is weight percent chromium, Mo is weight percent molybdenum, and N is weight percent nitrogen in the steel. In one form of the method, at least a portion of the article is remelted to homogenize the portion. In another form of the method, the article is annealed under conditions sufficient to homogenize at least a surface region of the article. The method of the invention enhances corrosion resistance of the stainless steel as reflected by the steel's critical crevice corrosion temperature.Type: GrantFiled: April 24, 2001Date of Patent: June 10, 2003Assignee: ATI Properties, Inc.Inventors: John F. Grubb, James D. Fritz
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Publication number: 20030084971Abstract: A duplex stainless steel includes less than, in weight percent, 3 percent nickel and 1.5 percent molybdenum. In one embodiment, the duplex stainless steel includes, in weight percent, up to 0.06 percent carbon; 15 to 25 percent chromium; 1 to less than 2.5 percent nickel; greater than 2 percent up to 3.75 percent manganese; greater than 0.12 up to 0.35 percent nitrogen; up to 2 percent silicon; up to 1.5 percent molybdenum; up to 0.5 percent copper; up to 0.2 percent cobalt; up to 0.05 percent phosphorous; up to 0.005 percent sulfur; 0.001 to 0.0035 percent boron; iron and incidental impurities. The duplex stainless steel provided may be provided in the form of an article of manufacture, such as strip, bar, plate, sheet, casting, tubing or piping. A method for making the duplex stainless steel of the invention also is disclosed.Type: ApplicationFiled: September 10, 2002Publication date: May 8, 2003Inventors: David S. Bergstrom, John J. Dunn, John F. Grubb, William A. Pratt
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Patent number: 6551420Abstract: A duplex stainless steel including, in weight percent, up to 0.06 percent carbon, 15 up to less than 25 percent chromium, greater than 3 up to 6 percent nickel, up to 3.75 percent manganese, 0.14 up to 0.35 percent nitrogen, up to 2 percent silicon, greater than 1.4 up to less than 2.5 percent molybdenum, up to less than 0.5 percent copper, up to less than 0.2 percent cobalt, up to 0.05 percent phosphorous, up to 0.005 percent sulfur, and 0.001 up to 0.0035 percent boron, with the remainder being iron and incidental impurities is disclosed. The duplex stainless steel may be included in an article of manufacture, such as a strip, bar, plate, sheet, casting, tubing or piping. A method for making such a duplex stainless steel is also disclosed.Type: GrantFiled: October 16, 2001Date of Patent: April 22, 2003Assignee: ATI Properties, Inc.Inventors: David S. Bergstrom, John J. Dunn, John F. Grubb, William A. Pratt
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Publication number: 20020139449Abstract: The invention relates to a transformation controlled nitride precipitation hardening heat-treatable steel with the following composition (data in wt. %): 15-18 Cr, max. 0.5 Mn, 4-10 Ni, max. 15 Co, max. 4 W, max. 4 Mo, 0.5-1 V, at least one of Nb, Ta, Hf and Zr totaling between 0.001-0.1, 0.001-0.05 Ti, max. 0.5 Si, max. 0.05 C, 0.13-0.25 N, max. 4 Cu, rest iron and usual impurities, under the condition that the weight ratio of vanadium to nitrogen V/N is in the range between 3.5 and 4.2. The invention also relates to a heat treatment process for this steel. Very good strength, ductility and also corrosion resistance can be attained. (FIG.Type: ApplicationFiled: December 5, 2001Publication date: October 3, 2002Inventor: Alkan Goecmen
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Publication number: 20020117239Abstract: The newly proposed ferritic stainless steel sheet consists of C up to 0.03 mass %, N up to 0.03 mass %, Si up to 2.0 mass %, Mn up to 2.0 mass %, Ni up to 0.6 mass %, 9-35 mass % Cr, 0.15-0.80 mass % Nb, optionally one or more of Ti up to 0.5 mass %, Mo up to 3.0 mass %, Cu up to 2.0 mass % and Al up to 6.0 mass %, and the balance being Fe except inevitable impurities, comprises metallurgical structure involving precipitates of 2 &mgr;m or less in particle size at a ratio not more than 0.5 mass % and has crystalline orientation on a rolled surface at ¼ depth of thickness with Integrated Density defined by the formula (a) not less than 1.2. The ferritic stainless steel sheet is manufactured by 25 hours or shorter precipitation-treatment at 700-850 ° C in prior to 1 minute or shorter finish-annealing at 900-1100 ° C. Integrated Intensity is made greater than 2.0 by controlling particle size of precipitates not more than 0.5 &mgr;m, so as to realize good workability with less in-plane anisotropy.Type: ApplicationFiled: December 21, 2001Publication date: August 29, 2002Applicant: NISSHIN STEEL CO., LTD.Inventors: Manabu Oku, Yoshitomo Fujimura, Yoshiaki Hori, Toshirou Nagoya, Yasutoshi Kunitake, Takeo Tomita
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Publication number: 20020074066Abstract: The invention relates to a process for producing wear-resistant edge layers on precipitation-hardenable materials, in particular precipitation-hardenable or martensite-hardened steels.Type: ApplicationFiled: December 15, 2000Publication date: June 20, 2002Applicant: Fraunhofer-Gesellschaft zur Forderung der angewandten Forschung e.V.Inventors: Berndt Brenner, Frank Tietz
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Publication number: 20020033210Abstract: High chromium ferritic steel containing chromium (Cr) in amount of 7˜12 weight %, one or two elements of molybdenum (Mu) and tungsten (W) as a solid-solution strengthening element, and one or more of elements for forming a MX carbonitride(s) is heat-treated at a temperature higher than both solid-solution temperature of the element(s) for forming the MX carbonitride(s) and a precipitation starting temperature of 6 ferrite for 5 seconds or longer, cooled at a rate of 0.5° C./s or faster, and subsequently tempered.Type: ApplicationFiled: January 8, 2001Publication date: March 21, 2002Inventors: Nobuyuki Fujitsuna, Masaaki Igarashi, Fujio Abe
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Patent number: 6340400Abstract: A stainless steel component comprising 0.8-1.4% carbon, 18-26 wt % chromium, 2-4 wt % nickel, 0-1 wt % molybdenum, 0 wt % lead and less than 0.6 wt % silicon provides for beneficial properties. Such a component may be prepared by the provision of an article from a steel starting material, and austenitizing the article between 800° C. and 1050° C. followed by hardening. In this process, the steel starting material comprises a powder.Type: GrantFiled: October 10, 2000Date of Patent: January 22, 2002Assignee: SKF Engineering & Research Centre B.V.Inventor: Xiao Bo Zhou
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Patent number: 6291079Abstract: The invention concerns a method for manufacturing steel wire comprising the following steps: manufacturing a reinforcing wire of sizeable length by rolling or hot wire drawing from steel containing the following elements: 0.18% to 0.45 % C, 0.4% to 1.8% Mn, 1% to 4% Cr, 0.1% to 0.6% Si, 0% to 1.5% Mo, 0% to 1.5% Ni, at most 0.01% S and 0.02% P, the reinforcing wire having, after being rolled or hot drawn, a temperature at least higher than the AC3 temperature, preferably by 50 to 200° C. and in particular by 100 to 150° C.; winding the wire in reels before air cooling the raw manufacturing wire to obtain a HRC hardness not less than 40 and preferably higher than 45. In a variant, the method consists in quenching and tempering so that the wire has a hardness between 20 HRC and 35 HRC. The invention also concerns a reinforcing wire and a flexible tube for carrying effluents.Type: GrantFiled: May 10, 1999Date of Patent: September 18, 2001Assignees: Institut Francais du Petrole, CoflexipInventors: José Mallen Herrero, François Ropital
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Patent number: 6248186Abstract: A ball-and-roller bearing is disclosed having an inner ring, an outer ring arranged on the axis of the inner ring and rotating around the co-axis relative to the inner ring, and a rolling body interposed between the inner ring and the outer ring and rolling with rotation of the outer ring relative to the inner ring. One of the inner ring, the outer ring, and the rolling body has a core member made from an alloy containing iron, at least one of 0.2 to 1.0% by weight of silicon and 0.2 to 1.5% by weight of manganese, 7.0 to 11.0% by weight of chromium, 1.5 to 6.0% by weight of molybdenum, and 0.5 to 8.0% by weight of cobalt, and a case hardened surface layer. Also disclosed is the method of manufacturing the bearing by forming a core member of the alloy, forming a case hardened layer containing 0.9 to 1.Type: GrantFiled: July 2, 1999Date of Patent: June 19, 2001Assignee: NSK Ltd.Inventors: Kenji Yamamura, Susumu Tanaka, Manabu Ohori
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Patent number: 6245163Abstract: An austenitic stainless steel having resistance to neutron-irradiation-induced deterioration obtained by subjecting a stainless steel consisting of not more than 0.08% by weight of C, not more than 2.0% by weight of Mn, not more than 1.5% by weight of Si, not more than 0.045% by weight of P, not more than 0.030% by weight of S, 8.0 to 22.0% of by weight Ni, 16.0 to 26.0% of by weight Cr and the balance as Fe; to thermal solid solution treatment at a temperature of 1,000° C. to 1,180° C. and then subjecting the so-treated steel to aging treatment at a temperature in the range of 600° C. to 750° C.Type: GrantFiled: April 19, 1999Date of Patent: June 12, 2001Assignee: Mitsubishi Heavy Industries, Ltd.Inventors: Toshio Yonezawa, Toshihiko Iwamura, Koji Fujimoto
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Patent number: 6245289Abstract: A refiner disk or disk segment cast from a stainless steel alloy having a composition of 0.2 percent to 0.6 percent carbon, 0.5 to 1.5 percent manganese, 0.5 percent to 1.5 percent silicon, a maximum of 0.05 percent sulfur, a maximum of 0.05 percent phosphorus, 14 percent to 18 percent chromium, 2 percent to 5 percent nickel, 2 percent to 4 percent copper, a maximum of 1 percent molybdenum, 1.5 percent to 5.0 percent niobium, a maximum of 1.5 percent vanadium, and a maximum of 0.5 percent total of at least one element selected from either rare earth metals and/or magnesium, the balance being iron. The niobium and vanadium form discrete carbides at high temperatures during the melting process. The rare earth metals and/or magnesium enhances the toughness of the disk by helping to shape the carbides and control them as discrete particles. Upon cooling, the carbides are preferably distributed evenly throughout the structure.Type: GrantFiled: October 20, 1998Date of Patent: June 12, 2001Assignee: J & L Fiber Services, Inc.Inventor: John Dodd
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Patent number: 6146478Abstract: A heat treatment process for material bodies made of a high-temperature-resistant iron-nickel superalloy of the type IN 706 comprises the following steps: solution annealing at approximately 965 to 995.degree. C. for 5 to 20 hours, stabilization annealing at approximately 775 to 835.degree. C. for 5 to 100 hours, and precipitation hardening at 715 to 745.degree. C. for 10 to 50 hours and at 595 to 625.degree. C. for 10 to 50 hours. A heat-treated material body of this kind, made of a high-temperature-resistant iron-nickel superalloy of the type IN 706 exhibits a crack growth rate of less than 0.05 mm/h and/or exhibits a minimum elongation of 2.5% without cracks at a constant strain rate of 0.05%/h and a temperature of 600.degree. C.Type: GrantFiled: October 22, 1997Date of Patent: November 14, 2000Assignee: Asea Brown Boveri AGInventors: Werner Balbach, Gunnar Harkeg.ang.rd, Reiner Redecker
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Patent number: 6106638Abstract: The subject of the invention is a process for manufacturing ferritic stainless steel strip, in which a strip of a ferritic stainless steel, of the type containing at most 0.12% of carbon, at most 1% of manganese, at most 1% of silicon, at most 0.040% of phosphorus, at most 0.030% of sulfur and between 16 and 18% of chromium, is solidified, directly from liquid metal, between two close-together, internally-cooled, counterrotating rolls with horizontal axes, wherein said strip is then cooled or left to cool so as to avoid making it remain within the austenite to ferrite and carbides transformation range, wherein said strip is coiled at a temperature of between 600.degree. C. and the martensitic transformation temperature Ms, wherein the coiled strip is left to cool at a maximum rate of 300.degree. C./h down to a temperature of between 200.degree. C. and ambient temperature and wherein said strip then undergoes box annealing.Type: GrantFiled: May 11, 1998Date of Patent: August 22, 2000Assignee: UsinorInventors: Philippe Paradis, Philippe Martin
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Patent number: 6099668Abstract: A method for producing an exhaust valve is described, comprising subjecting a raw material of a specified heat resisting alloy to solid solution treatment; forming a head portion of the exhaust valve from the solution treated raw material through cold working or warm working; joining a stem portion made of martensitic heat resisting steel to said head portion of the exhaust valve; and subjecting the head portion and the stem portion joined with each other to aging treatment.Type: GrantFiled: July 13, 1998Date of Patent: August 8, 2000Assignee: Daido Tokushuko Kabushiki KaishaInventors: Shigeki Ueta, Toshiharu Noda, Michio Okabe
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Patent number: 5976275Abstract: The present invention aims at providing structural materials having a resistance to degradation by neutron irradiation, causing no SCC in an environment of light-water reactors even after subjecting the materials to neutron irradiation of approximately at least 1.times.10.sup.22 n/cm.sup.2 (E>1 MeV), and having thermal expansion coefficients approximately similar to that of structural materials. The high nickel austenitic stainless steels of the present invention having a resistance to degradation by neutron irradiation can be produced by subjecting stainless steels having compositions (by weight %) of 0.005 to 0.08% of carbon, at most 0.3% of Mn, at most 0.2% of (Si+P+S), 25 to 40% of Ni, 25 to 40% of Cr, at most 3% of Mo or at most 5% of (Mo+W), at most 0.3% of Nb+Ta, at most 0.3% of Ti, at most 0.001% of B and the balance of Fe to a solution-annealing treatment at a temperature of 1000 to 1150.degree. C.Type: GrantFiled: June 5, 1997Date of Patent: November 2, 1999Assignee: Mitsubishi Jukogyo Kabushiki KaishaInventors: Toshio Yonezawa, Toshihiko Iwamura, Hiroshi Kanasaki, Koji Fujimoto, Shizuo Nakada, Kazuhide Ajiki, Mitsuhiro Nakamura
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Patent number: 5911842Abstract: A heat resisting steel whose metal structure is entirely martensite phase produced by tempering after quenching. The steel comprises, by weight, 0.05 to 0.20% C, not more than 0.15% Si, not more than 1.5% Mn, not more than 1.0% Ni, 8.5 to 13.0% Cr, not more than 3.50% Mo, not more than 3.5% W, 0.05 to 0.30% V, 0.01 to 0.20% Nb, not more than 5.0% Co, 0.001 to 0.020% boron, 0.005 to 0.040% nitrogen, 0.0005 to 0.0050% oxygen and 0.00001 to 0.0002% hydrogen. The steel has preferably not more than 10 of the Cr equivalent. The steel has 10 kgf/mm.sup.2 or more of 100,000 hours creep rupture strength at 650.degree. C.Type: GrantFiled: April 30, 1997Date of Patent: June 15, 1999Assignees: Hitachi, Ltd., The Japane Steel Works, Ltd.Inventors: Masao Shiga, Kishio Hidaka, Norio Yamada, Shigeyoshi Nakamura, Yutaka Fukui, Nobuo Shimizu, Ryoichi Kaneko, Yasuhiro Harada, Yasuo Watanabe, Toshio Fujita, Norio Morisada, Yasuhiko Tanaka
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Patent number: 5861068Abstract: Stainless steel is improved in anti-microbial property by the addition of Cu in an amount of 0.4-5.0 wt. % and the precipitation of Cu-rich phase at the ratio of 0.2 vol. % or more. The Cu-rich phase is precipitated as minute particles uniformly dispersed in the matrix not only at the surface layer but also at the interior by heat treatment such as annealing or aging at 500.degree.-900.degree.. Since the anti-microbial property is derived from the material itself, the underlying stainless steel does not lose the excellent anti-microbial property even after it is polished or mechanically worked. Due to the anti-microbial property, the stainless steel is useful as material in various fields requiring sanitary environments, for example, kitchen goods, electric home appliances, devices or tools at hospitals, parts or interiors for building and grips or poles for electric trains or buses.Type: GrantFiled: December 13, 1996Date of Patent: January 19, 1999Assignee: Nisshin Steel Co., Ltd.Inventors: Morihiro Hasegawa, Katsuhisa Miyakusu, Naoto Okubo, Sadayuki Nakamura
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Patent number: 5843246Abstract: A method for producing a dual phase ferrite-martensite steel product from a cold rolled stainless steel. The method includes a step of rapidly heating the steel to annealing temperature in less than 30 seconds, followed by a step of cooling the heated steel at a cooling rate sufficient to transform austenite to martensite.Type: GrantFiled: January 16, 1996Date of Patent: December 1, 1998Assignee: Allegheny Ludlum CorporationInventors: Yeong-U Kim, Lewis L. Kish
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Patent number: 5824265Abstract: A refiner disk or disk segment is cast from a stainless steel alloy having a composition of 0.2 percent to 0.4 percent carbon, 0.5 to 1.5 percent manganese, 0.5 percent to 1.5 percent silicon, a maximum of 0.05 percent sulfur, a maximum of 0.05 percent phosphorus, 14 percent to 18 percent chromium, 2 percent to 5 percent nickel, 2 percent to 5 percent copper, a maximum of 1 percent molybdenum, and 1.5 percent to 2.5 percent niobium, the balance being iron. The Niobium forms discrete carbides at high temperatures during the melting process. Upon cooling, the carbides are distributed evenly throughout the structure. This resultant alloy provides toughness and corrosion resistance like a lower carbon alloy plus increased wear resistance due to the carbide formation. The alloy utilizes chromium to impart corrosion resistance, the process of tying up carbon as discrete, non-chromium carbides increases the amount of chromium present to provide corrosion resistance.Type: GrantFiled: April 24, 1996Date of Patent: October 20, 1998Assignee: J & L Fiber Services, Inc.Inventor: John Dodd
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Patent number: 5783001Abstract: A method of heat treating and cleaning maraging or precipitation hardening stainless steel surgical needles is disclosed. The method comprises exposing the surgical needles to a partial vacuum at a temperature less than the aging temperature to remove volatile surface contaminants. Then the needles are heat treated in an argon gas environment at a pressure equal to or greater than 1.0 atmosphere.Type: GrantFiled: November 14, 1996Date of Patent: July 21, 1998Assignee: Ethicon, Inc.Inventors: Timothy Sardelis, Douglas Warren Ackerman, William McJames
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Patent number: 5759308Abstract: A precipitation hardened metallic alloy is provided in which the strengthening is based on the precipitation of particles. The strengthening particles have a quasicrystalline structure, said structure being essentially maintained at aging times up to 1000 h and tempering treatments up to 650.degree. C., the strengthening involving an increase in tensile strength of at least 200 MPa.Type: GrantFiled: January 3, 1997Date of Patent: June 2, 1998Assignee: Sandvik ABInventors: Anna Hultin-Stigenberg, Jan-Olof Nilsson, Ping Liu
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Patent number: 5632826Abstract: A precipitation hardened metallic alloy is provided in which the strengthening is based on the precipitation of particles. The strengthening particles have a quasicrystalline structure, said structure being essentially maintained at aging times up to 1000 h and tempering treatments up to 650.degree. C., the strengthening involving an increase in tensile strength of at least 200 MPa.Type: GrantFiled: October 7, 1994Date of Patent: May 27, 1997Assignee: Sandvik ABInventors: Anna Hultin-Stigenberg, Jan-Olof Nilsson, Ping Liu
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Patent number: 5605587Abstract: Martensitic steel components of apparatus for magnetic conditioning of liquids which are subjected to cathodic reaction and degradation are treated prior to use to form a barrier of iron-chromium oxide and a uniform level of hardness throughout by heating the steel to a temperature near the grain boundary temperature of the steel, maintaining that temperature for a specified period and then rapidly quenching the steel.Type: GrantFiled: April 7, 1995Date of Patent: February 25, 1997Assignee: Hydrodynamics CorporationInventor: John H. Meckling
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Patent number: 5599408Abstract: .epsilon. phase precipitates in the matrix having a composition of 0.07% or less carbon, 1 or less silicon, 1% or less manganese, 2.5 to 5% copper, 3 to 5.5% nickel, 14 to 17.5% chromium, 0.5% or less molybdenum, 0.15 to 0.45% niobium, by weight, and the balance composed substantially of iron, and comprising 6 to 30 vol % austenitic phase and the balance composed substantially of martensitic phase. In a method of producing a structural member in which first solution treatment is performed at 1010.degree. to 1050.degree. C. on a stainless steel having a composition described above and first aging treatment is performed at a temperature not lower than 520.degree. C. and not higher than 630.degree. C., second solution treatment is performed at 730.degree. to 840.degree. C., and then second aging treatment is performed at a temperature not lower than 520.degree. C. and not higher than 630.degree. C. or a structural member of any shape is fabricated by means of welding work before the second solution treatment.Type: GrantFiled: May 4, 1994Date of Patent: February 4, 1997Assignee: Mitsubishi Jukogyo Kabushiki KaishaInventors: Akitsugu Fujita, Takayuki Kawano, Makoto Nakamura, Fumikazu Sakai, Tatsuki Matsumoto, Shinsuke Oba, Hidetoshi Sueoka, Manabu Kimura, Masato Zama, deceased
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Patent number: 5514329Abstract: A fluid impeller for us in applications requiring superior cavitation erosion resistance. The impeller has a body fabricated from a castable metastable austenitic steel alloy which has a preferred chemical composition in the range of 17.5-18.5% chromium, 0.5-0.75% nickel, 0.45-55% silicon, 0.2-0.25% nitrogen, 15.5-16.0% manganese and 0.1%-0.12% carbon. Quantitative testing has shown cavitation resistance of four to six times that of standard boiler feed pump materials. A method for making cavitation resistant fluid impellers is also disclosed.Type: GrantFiled: June 27, 1994Date of Patent: May 7, 1996Assignee: Ingersoll-Dresser Pump CompanyInventors: Colin McCaul, Vincenzo Fumagalli
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Patent number: 5496421Abstract: A high strength martensitic stainless steel contains:0.06 wt. % or less C, 12 to 16 wt. % Cr, 1 wt. % or less Si, 2 wt. % or less Mn, 0.5 to 8 wt. % Ni, 0.1 to 2.5 wt. % Mo, 0.3 to 4 wt. % Cu, 0.05 wt. % or less N, and the balance being Fe and inevitable impurities;said steel having an area ratio of .delta.-ferrite phase of at most 10%; andsaid steel having fine copper precipitates dispersed in a matrix.And further a method for making the stainless steel comprises austenitizing, cooling and tempering.Type: GrantFiled: October 17, 1994Date of Patent: March 5, 1996Assignee: NKK CorporationInventors: Shuji Hashizume, Yusuke Minami, Yoshiichi Ishizawa
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Patent number: 5433801Abstract: Steel which is particularly useful for making a razor blade of high corrosion resistance contains more than 0.45%, but less than 0.55%, of carbon, 0.4 to 1.0% of silicon, 0.5 to 1.0% of manganese, 12 to 14% of chromium and 1.0 to 1.6% of molybdenum, all by weight, in addition to iron and inevitable impurities, and has a carbide density of 100 to 150 particles per 100 square microns as annealed. The razor blade has a Vickers hardness of at least 620 and a carbide density of 10 to 45 particles per 100 square microns, and preferably has a specific distribution of residual austenite content. The improved properties of the razor blade are achieved by an improved process of heat treatment which includes austenitizing the steel at a temperature of 1075.degree. C. to 1120.degree. C., cooling it to a temperature between -60.degree. C. and -80.degree. C. for hardening it, and tempering it at a temperature of 250.degree. C. to 400.degree. C.Type: GrantFiled: October 15, 1993Date of Patent: July 18, 1995Inventors: Wolfgang Althaus, Atsushi Kumagai
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Patent number: 5358577Abstract: A high strength, high toughness stainless steel consisting, by weight, of C more than 0.16% but less than 0.25%, Si not more than 2.0%, Mn not more than 1.0%, Ni not more than 2.0%, Cr from 11 to 15%, Mo not less than 0.5% but less than 3.0%, Co from 12 to 21%, at least one kind selected from the group consisting of V from 0.1 to 0.5% and Nb less than 0.1% which at least one kind is added as occasion demands, and the balance Fe and incidental impurities. This steel is produced by a method comprising the steps of: preparing a stainless steel having the composition of any one of the claims 1 to 4; subjecting the stainless steel to a solution heat treatment at a temperature of 950 to 1150.degree. C.; quenching the steel; subjecting the steel to a sub zero treatment at a temperature of -50.degree. to -100.degree. C.; and subjecting the steel to a tempering at a temperature of 120.degree. to 450.degree. C.Type: GrantFiled: July 20, 1993Date of Patent: October 25, 1994Assignees: Hitachi Metals, Ltd., The Society of Japanese Aerospace Companies, Inc., Sumitomo Precision Products Co., Ltd.Inventors: Toshihiro Uehara, Rikizo Watanabe, Nobuhito Nakama
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Patent number: 5310431Abstract: An iron-based, corrosion-resistant, precipitation strengthened, martensitic steel essentially free of delta ferrite for use at high temperatures has a nominal composition of 0.05-0.1 C, 8-12 Cr, 1-5 Co, 0.5-2.0 Ni, 0.41-1.0 Mo, 0.1-0.5 Ti, and the balance iron. This steel is different from other corrosion-resistant martensitic steels because its microstructure consists of a uniform dispersion of fine particles, which are very closely spaced, and which do not coarsen at high temperatures. Thus at high temperatures this steel combines the excellent creep strength of dispersion-strengthened steels, with the ease of fabricability afforded by precipitation hardenable steels.Type: GrantFiled: October 7, 1992Date of Patent: May 10, 1994Assignee: Robert F. BuckInventor: Robert F. Buck
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Patent number: 5288347Abstract: A high strength, high toughness stainless steel consisting, by weight, of C more than 0.16% but less than 0.25%, Si not more than 2.0%, Mn not more than 1.0%, Ni not more than 2.0%, Cr from 11 to 15%, Mo not less than 0.5% but less than 3.0%, Co from 12 to 21%, at least one kind selected from the group consisting of V from 0.1 to 0.5% and Nb less than 0.1% which at least one kind is added as occasion demands, and the balance Fe and incidental impurities. This steel is produced by a method comprising the steps of: preparing a stainless steel having the composition of any one of the claims 1 to 4; subjecting the stainless steel to a solution heat treatment at a temperature of 950.degree. to 1150.degree. C.; quenching the steel; subjecting the steel to a sub zero treatment at a temperature of -50 to -100.degree. C.; and subjecting the steel to a tempering at a temperature of 120.degree. to 450.degree. C.Type: GrantFiled: June 4, 1992Date of Patent: February 22, 1994Assignees: Hitachi Metals, Ltd., Society of Japanese Aerospace Companies, Inc., Sumitomo Precision Products Co., Ltd.Inventors: Toshihiro Uehara, Rikizo Watanabe, Nobuhito Nakama
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Patent number: 5178693Abstract: A process for the production of a stainless steel strip having excellent spring characteristics as such and good formability, wherein a cold rolled strip of a stainless steel comprising, in addition to Fe, from 10.0 to 20.0% by weight of Cr, from 0.01 to 0.15% by weight of C, and at least one of Ni, Mn and Cu in an amount of from 0.1 to 4.0% by weight, is continuously passed through a continuous heat treatment furnace where it is heated to a temperature range for a two-phase of ferrite and austenite, rapidly cooled to provide a strip of a duplex structure, consisting essentially of ferrite and martensite, optionally temper rolled at a rolling reduction of not more than 10%, and continuously passed through a continuous heat treatment furnace to effect aging of not longer than 10 minutes.Type: GrantFiled: March 15, 1991Date of Patent: January 12, 1993Assignee: Nisshin Steel Co., Ltd.Inventors: Katsuhisa Miyakusu, Teruo Tanaka, Hiroshi Fujimoto, Chizui Toyokihara