Carburizing Or Nitriding Uniformly Throughout The Entire Mass (i.e., Internal Carburizing) Patents (Class 148/207)
  • Patent number: 11492693
    Abstract: Process for pre-treatment of a surface of a chromium containing corrosion resistant metallic substrate prior to further processing, wherein the metallic substrate is brought into contact with an in-situ generated activating agent, being the thermal decomposition product of a hydrofluoroolefin, the substrate and the activating agent are heated, and optionally the activating agent is partly or entirely removed before further processing.
    Type: Grant
    Filed: September 11, 2018
    Date of Patent: November 8, 2022
    Assignee: BORTEC GMBH
    Inventors: Ralph Hunger, Andreas Hunger, Robin Berger
  • Patent number: 10697054
    Abstract: A low temperature carburizing method according to the present invention comprises: step (a) for pre-processing a metal to be processed; step (b) for inputting the metal to be processed to a reaction chamber and heating the same to a set temperature; step (c) for forming a vacuum atmosphere in the reaction chamber and introducing a reaction gas thereinto at a predetermined pressure to accelerate carburization; step (d) for supplying the reaction gas to the reaction chamber at a pressure equal to or lower than the pressure of the reaction gas of step (c) to spread carburization; and step (e) for repeating step (c) and step (d) at predetermined time intervals.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: June 30, 2020
    Assignee: KOREA INSTITUTE OF INDUSTRIAL TECHNOLOGY
    Inventors: Jun Ho Kim, Kyu Sik Kim, Uoo Chang Jung, In Wook Park
  • Patent number: 10094006
    Abstract: The present invention is related to a method of fabricating an aluminum matrix composite by a simple process of heating a mixture of a ceramic reinforcing phase and aluminum in nitrogen containing atmosphere and an aluminum matrix composite fabricated by the same. The aluminum matrix composite may be fabricated by heating to temperatures even lower than the melting temperature of aluminum as well as to temperatures higher. The exothermic nitridation reaction contributes to the melting of the aluminum matrix and the aluminum nitride formed in-situ as a result may act as an additional reinforcing phase.
    Type: Grant
    Filed: July 6, 2015
    Date of Patent: October 9, 2018
    Assignees: ALCOM, SENUS CORP.
    Inventors: Kon-Bae Lee, Jae-Pyoung Ahn, Hae Sung Kim, Hyunjoo Choi
  • Patent number: 9738963
    Abstract: In a method for manufacturing a ferritic stainless steel product, a ferritic stainless steel object is heated in an inert gas atmosphere including nitrogen gas in a heating furnace at a nitriding temperature higher than or equal to a transformation temperature so as to form a nitrided layer on a surface of the ferritic stainless steel object. Moreover, the nitriding temperature is set lower than 1100° C. during the heating. The heating of the ferritic stainless steel object is performed in a state where a solid carbon exists inside the heating furnace.
    Type: Grant
    Filed: March 20, 2014
    Date of Patent: August 22, 2017
    Assignee: DENSO CORPORATION
    Inventors: Teppei Watanabe, Atsushi Iwase
  • Patent number: 9561251
    Abstract: Pharmaceutical compositions for oral administration, in particular administration as an oral delivery system to be swallowed directly or capable of disintegration in the oral cavity, comprising iron oxy-hydroxide in high loading.
    Type: Grant
    Filed: November 13, 2008
    Date of Patent: February 7, 2017
    Assignee: Vifor Fresenius Medical Care Renal Pharma Ltd.
    Inventors: Ludwig Daniel Weibel, Erik Philipp
  • Patent number: 9414924
    Abstract: A new composition and medical implant made there from comprises a thick diffusion hardened zone, and layered ceramic surface. Orthopedic implants comprising the new composition, methods of making the new composition, and methods of making orthopedic implants comprising the new composition are disclosed.
    Type: Grant
    Filed: March 29, 2013
    Date of Patent: August 16, 2016
    Assignee: Smith & Nephew, Inc.
    Inventors: Vivek Devidas Pawar, Shilesh C. Jani, Carolyn L. Weaver
  • Patent number: 8608867
    Abstract: A method for the individualization of a metallic material by means of a carbon-containing basic material of organic origin is proposed. The novel method makes it possible to produce individualized ornamental alloys and individualized symbolic articles, such as pieces of jewelry, in a first step a carbon-containing organic basic material, which originates from at least one specific clearly identifiable person or a clearly identifiable group of persons, being converted into a carbonized initial material, and, in a second step, a physical and chemical incorporation of at least a fraction of the carbonized initial material into the metallic material taking place. The novel method and the novel ornamental alloys make it possible to produce symbolic articles with a direct material or substantive relation to a desired person by simple means, without creative freedom being restricted.
    Type: Grant
    Filed: December 3, 2007
    Date of Patent: December 17, 2013
    Inventor: Markus Spühler
  • Patent number: 8337639
    Abstract: A mixed powder layer is applied by coating to a cavity of a forging die made of an Fe-base alloy, at least to the region of the cavity to be reinforced or repaired, the mixed powder layer comprising the first element powder capable of being converted into a carbide to enhance the hardness of the forging die and the second element powder having a melting point lower than that of the first element powder. Die reinforcing is carried out by forging a work by using a forging die covered with the mixed powder layer and heat-treating the die by utilizing the working heat generated in the forging to thereby make the layer reflow and diffuse the carbide in the die.
    Type: Grant
    Filed: October 26, 2006
    Date of Patent: December 25, 2012
    Assignee: Honda Motor Co., Ltd.
    Inventors: Toshimasa Kumaki, Mitsuo Kuwabara, Kazuo Matsushita
  • Patent number: 8211244
    Abstract: The present invention relates to a method for manufacturing tantalum carbide which can form tantalum carbide having a prescribed shape using a simple method, can form the tantalum carbide having a uniform thickness even when the tantalum carbide is coated on the surface of an article and is not peeled off by a thermal history, tantalum carbide obtained by the manufacturing method, wiring of tantalum carbide, and electrodes of tantalum carbide, where the tantalum carbide is formed on the surface of tantalum or a tantalum alloy by placing the tantalum or tantalum alloy in a vacuum heat treatment furnace, heat-treating the tantalum or tantalum alloy under a condition where a native oxide layer of Ta2O5 formed on the surface of tantalum or tantalum alloy is sublimated to remove the Ta2O5, introducing a carbon source into the vacuum heat treatment furnace, and then heat-treating.
    Type: Grant
    Filed: May 17, 2010
    Date of Patent: July 3, 2012
    Assignee: Toyo Tanso Co., Ltd.
    Inventors: Tadaaki Kaneko, Yasushi Asaoka, Naokatsu Sano
  • Publication number: 20120111454
    Abstract: A process for the high temperature carburization of steel comprising heating said steel in a vacuum furnace in the presence of a hydrocarbon carburizing gas in combination with hydrogen wherein said carburizing gas/hydrogen combination is administered to the vacuum furnace by cyclically reducing the pressure in the furnace followed by the pulsed addition of the hydrocarbon carburizing gas with hydrogen at partial pressure followed by a second diffusion cycle wherein the steel is further annealed for a time sufficient to allow for the additional deposition of from about 0.8% to about 3.0% m/o of said carbon onto the surface of said steel to permit the further migration of the carbon from the steel surface to the interior thereof.
    Type: Application
    Filed: December 23, 2011
    Publication date: May 10, 2012
    Inventor: Kenneth H. Moyer
  • Publication number: 20100236666
    Abstract: A method of processing a superalloy powder includes mechanically alloying nitrogen with superalloy powder particles having at least one nitride-forming element such that each superalloy powder particle includes a microstructure having nitrogen dispersed throughout the microstructure. The powder may then be formed into an article having nitride regions dispersed throughout.
    Type: Application
    Filed: March 19, 2009
    Publication date: September 23, 2010
    Inventor: Clifford C. Bampton
  • Patent number: 7650710
    Abstract: A body of iron, steel or other such ferrous material is protected from thermochemical erosion by a layer of an iron nitride having a relatively low nitrogen content. The atomic percentage of nitrogen in the iron nitride layer is no greater than 20%, and in specific embodiments is in the range of 10-15%. The nitride layer may have a layer of a refractory material deposited thereatop. Some refractory materials include metals such as chromium. The invention has specific utility for protecting gun barrels, turbines, internal combustion engines, drilling equipment, machine tools, aerospace systems and chemical reactors which are exposed to extreme conditions of temperature and pressure. Specifically disclosed is a gun barrel which incorporates the invention.
    Type: Grant
    Filed: June 3, 2004
    Date of Patent: January 26, 2010
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Paul J. Conroy, James M. Garner, Charles Leveritt
  • Publication number: 20090218011
    Abstract: The invention relates to a method for making a thin finished product to be formed by deformation that combines strength with resistance to a highly corrosive environment. The method comprises forming a sheet of stainless steel with a microstructure consisting predominantly of ferrite, austenite, martensite or a mixture thereof, with a thickness of less than 3 mm, to a three dimensional semi finished product, treating said semi finished product with a nitrogen-containing atmosphere at a temperature of between 1000° C. and 1200° C. during a time and under a nitrogen pressure, sufficient to saturate the product through the thickness with a nitrogen content between a lower limit of 0.3 wt % and an upper limit that is provided by the beginning of nitride separation, cooling down said product at such a rate and nitrogen pressure that nitride separation is avoided, and subsequently machining the nitrogen saturated semi- finished product to the finished product.
    Type: Application
    Filed: June 12, 2006
    Publication date: September 3, 2009
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Hubert Sjoerd Blaauw, Martin Hommes, Lucius Theodorus Vinkenvleugel
  • Patent number: 7506440
    Abstract: A method for surface treating a titanium gas turbine engine component. The method includes providing a gas turbine engine component having a titanium-containing surface. The component is heated to a temperature sufficient to diffuse carbon into the titanium and below 1000° F. The surface is contacted with a carbon-containing gas to diffuse carbon into the surface to form carbides. Thereafter, the carbide-containing surface is coated with a lubricant comprising a binder and a friction modifier. The binder preferably including titanium oxide and the friction modifier preferably including tungsten disulfide. The coefficient of friction between the surface and another titanium-containing surface is less than about 0.6 in high altitude atmospheres.
    Type: Grant
    Filed: October 11, 2005
    Date of Patent: March 24, 2009
    Assignee: General Electric Company
    Inventor: Robert William Bruce
  • Publication number: 20090008892
    Abstract: A spherical plain bearing for a heavy haul truck strut includes an outer ring and an inner ring. The outer ring includes an outer ring core disposed between a concave spherical first bearing surface and an exterior mounting surface. The inner ring includes an inner ring core disposed between a convex spherical second bearing surface and an interior surface. The inner ring is disposed within the outer ring with the first bearing surface engaging the second bearing surface. At least a portion of at least one of the first bearing surface, the second bearing surface, the exterior mounting surface and the interior surface has a hardness greater than that of at least one of the outer ring core and the inner ring core, for providing wear and impact resistance.
    Type: Application
    Filed: June 6, 2008
    Publication date: January 8, 2009
    Applicant: Roller Bearing Company of America, Inc.
    Inventor: Brian Gaumer
  • Patent number: 7470309
    Abstract: The present invention relates to an economically excellent method for manufacturing ultra fine tungsten carbide-cobalt composite powder having tungsten compound and cobalt compound as its raw material. More particularly, the present invention provides a manufacturing method comprising a process for mixing tungsten compounds, cobalt compounds, grain-grown inhibitor compounds and oxide in a mechanical method, a calcination process for removing ammonia and moisture of the mixed powder and forming it into an composite oxide, a reduction process for manufacturing said calcined powder into pure metal powder, a mixing process for adding carbon source to said reduced powder, and a carburization process for manufacturing the mixed powder into a tungsten carbide-cobalt composite powder, which is the final form. Using the manufacturing method of the present invention, ultra-fine tungsten carbide-cobalt composite powder having an ultra-fine particle size of 0.1˜0.2 ?m, 0.2˜0.3 ?m,0.3˜0.
    Type: Grant
    Filed: April 27, 2006
    Date of Patent: December 30, 2008
    Assignee: Nanotech Co., Ltd.
    Inventors: Sang-Myun Kim, Hyun-Ho Lee, Min-Sun Hur
  • Patent number: 7442261
    Abstract: In a method of producing an iron-based alloy containing chromium carbide, pieces of cemented carbide are added to an iron-based melt containing carbon, e.g. cast iron. Chromium, which regulates the solution of WC into the melt, is also added. The molten alloy is then cast. An alloy comprising chromium-tungsten-carbide in a ferrous matrix is produced. Uses of the alloy are claimed.
    Type: Grant
    Filed: May 15, 2001
    Date of Patent: October 28, 2008
    Assignee: Proengco Tooling AB
    Inventors: Mikael Andersson, legal representative, Henrik Andersson, legal representative, Helena Andersson, legal representative, Anders Nilsson, Jan-Eric Ståhl, Carl-Håkan Andersson
  • Patent number: 7442225
    Abstract: The present invention provides a worked molybdenum-alloy material that can be used at higher temperatures than at least temperatures at which known TZM alloys are used. A worked molybdenum-alloy material having high strength and high toughness includes at least one of carbide particles, oxide particles, and boride particles and fine nitride particles dispersed by internal nitriding of an untreated worked molybdenum-alloy material in which a nitride-forming-metal element is dissolved to form a solid solution in a molybdenum matrix and at least one of carbide particles, oxide particles, and boride particles is precipitated and dispersed.
    Type: Grant
    Filed: March 27, 2003
    Date of Patent: October 28, 2008
    Assignees: Japan Science and Technology Agency, National University Corporation Okayama University, A.L.M.T. Corp.
    Inventors: Jun Takada, Masahiro Nagae, Makoto Nakanishi, Tomohiro Takida, Tetsushi Hoshika
  • Patent number: 7063821
    Abstract: Apparatus for producing molybdenum carbide from a precursor material includes a supply of process gas and a furnace defining at least a first heating zone and a second heating zone. The furnace heats the first heating zone to a first temperature and the second heating zone to a second temperature. The second temperature is at least about 100° C. hotter than the first temperature. A transfer system operatively associated with the furnace and the supply of process gas moves the precursor material through the first and second heating zones and in the presence of the process gas to form molybdenum carbide (MoC and Mo2C).
    Type: Grant
    Filed: September 3, 2003
    Date of Patent: June 20, 2006
    Assignee: Cyprus Amax Minerals Company
    Inventors: Mohamed H. Khan, Joel A. Taube
  • Patent number: 6969430
    Abstract: This invention is directed to a process and apparatus for producing high productivity carburizing. A process is introduced that uses a gas mixture made up of CO, H2, CO2, H2O, CH4 and N2, such that the product of the % CO and % H2 is greater than about 1600; the ratio of CO/CO2 is greater than 10; and the ratio of H2/H2O is greater than about 10. The gas mixture is controlled for a short time. A reactor for generating a gas mixture for carburizing steel is also introduced. This reactor is composed of a cylindrically symmetric body; a first central tube containing electrical heating elements for gas flow; a second central tube concentrically disposed around the first central tube; and a plurality of catalyst beds disposed in an annular space in a segmented fashion around the second central tube.
    Type: Grant
    Filed: June 5, 2002
    Date of Patent: November 29, 2005
    Assignee: Praxair Technology, Inc.
    Inventors: Jaak Stefaan Van den Sype, Alan Russell Barlow, Edison Viotto
  • Patent number: 6908691
    Abstract: The aim of the invention is to provide a metal strip for epitaxial coating with a biaxially textured layer, this metal strip, however, being able to be produced in an uncomplicated manner and having a high tensile strength, low magnetic losses and/or a high electrical conductivity. According to the invention, the metal strip is comprised of Nj, Cu, Ag or alloys thereof all serving as basic material, whereby the one-layer metal strip and, in the instance of a multilayer metal strip, at least one of its layers contains 10 nm to 5 ?m large, strength-increasing dispersoids comprised of carbides, borides, oxides and/or nitrides with a volume proportion ranging from 0.1 to 5%. In the instance of a multilayer metal strip, the layers form a composite, and at least one of the layers does not contain any dispersoids and has a biaxial texture. For the production, a starting material is used, which is comprised of Ni, Cu, Ag or of alloys thereof all serving as basic material and which contains 0.
    Type: Grant
    Filed: December 5, 2001
    Date of Patent: June 21, 2005
    Assignee: Institut fuer Festkoerper-und Werkstoffforschung Dresden e.V.
    Inventors: Bernd De Boer, Bernhard Holzapfel, Gunter Risse
  • Patent number: 6471790
    Abstract: The invention relates to a process for the forming of precipitates of carbides and borides along the grain boundaries of an component made from an Ni based superalloy while in solid state. This follows from the finding that the carbides formed by carburization offer similar grain boundary strengthening properties as those cast into the article using the current art without the detrimental effects of adding more carbon to the alloy prior to casting. With advantage the process will be carried out in a way to form secondary caribides in the form Cr23C6, Cr7C, Cr6C and HfC and may take place before, during or after the normal solution and/or precipitation hardening heat treatments of the component.
    Type: Grant
    Filed: August 9, 2000
    Date of Patent: October 29, 2002
    Assignee: ALSTOM (Switzerland) Ltd
    Inventor: John Fernihough
  • Patent number: 6260266
    Abstract: A silicon substrate on which a silicon dioxide film having a groove is formed is placed on a sample stage disposed in a vacuum chamber. Subsequently, a titanium film and a tungsten film are deposited sequentially on the silicon dioxide film. The surface of the tungsten film is nitrided by using a plasma under the pressure maintained at 10 Pa or higher inside the vacuum chamber, so as to form a tungsten nitride film. After a copper film is deposited on the tungsten nitride film, the portions of the titanium film, tungsten film, tungsten nitride film, and copper film located outside the groove are removed, thus forming a buried interconnecting wire made of copper.
    Type: Grant
    Filed: November 8, 1996
    Date of Patent: July 17, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Tokuhiko Tamaki
  • Patent number: 5908486
    Abstract: Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains.
    Type: Grant
    Filed: April 26, 1996
    Date of Patent: June 1, 1999
    Assignee: Lockheed Martin Idaho Technologies Company
    Inventors: John E. Flinn, Thomas F. Kelly
  • Patent number: 5746803
    Abstract: A transition metal carbide-Group VIII metal powder comprising discrete particles of a transition metal carbide and Group VIII metal wherein: substantially all of the particles have a size of at most 0.4 micrometer; the transition metal carbide is selected from carbides of the group consisting of tungsten, titanium, tantalum, molybdenum, zirconium, hafnium, vanadium, niobium, chromium, mixtures and solid solutions thereof; and the Group VIII metal is selected from the group consisting of iron, cobalt, nickel, mixtures and solid solutions thereof. Said powders are produced by heating an admixture comprising a finishing source of carbon (e.g., acetylene black), a source of a group VIII metal (e.g., Co.sub.3 O.sub.
    Type: Grant
    Filed: June 4, 1996
    Date of Patent: May 5, 1998
    Assignee: The Dow Chemical Company
    Inventors: Stephen D. Dunmead, Michael J. Romanowski
  • Patent number: 5498299
    Abstract: The surface oxidation under carburization temperatures of steels during the carburization with carbon-containing gas mixtures is avoided by heating the steels to the carburization temperature under a nitrogen/hydrogen mixture or pure hydrogen. For carburization, these gases are replaced by a carbon-containing gas mixture whose oxygen activity is smaller than that required for the formation of manganese(II) oxide or chromium(III) oxide.
    Type: Grant
    Filed: October 6, 1994
    Date of Patent: March 12, 1996
    Assignee: Messer Griesheim GmbH
    Inventor: Hans-Peter Schmidt
  • Patent number: 5336292
    Abstract: A sintered body of titanium-based carbonitride alloy according to the invention comprises carbonitride hard constituents in 5-25% binder phase where the hard constituents contain, in addition to Ti, one or more of the metals Zr, Hf, V, Nb, Ta, Cr, Mo and/or W and the binder phase is based on cobalt and/or nickel. The sintered body has at least one outer surface with a <50 .mu.m thick surface layer of a titanium-rich cubic carbonitride. Below this layer there is a <100 .mu.m thick binder phase enrichment zone. The binder phase content can be >1.2 of that in the inner part of the body D. Under the binder phase enrichment zone, there is a <250 .mu.m thick binder phase depleted zone C. The binder phase content in this zone has a lowest level <0.9 of the binder phase content in the inner part of the body D.Such sintered bodies are manufactured by heat treatment in an atmosphere of N.sub.2 and/or NH.sub.3 possibly in combination with at least one of CH.sub.4, CO and CO.sub.2 at 1100.degree.-1350.
    Type: Grant
    Filed: June 15, 1992
    Date of Patent: August 9, 1994
    Assignee: Sandvik AB
    Inventors: Gerold Weinl, Marian Mikus
  • Patent number: 5336291
    Abstract: In order to produce easily and at low cost a metallic composite material incorporating metal carbide particles dispersed therein such that fine TiC particles and/or ZrC particles are uniformly dispersed in a matrix of Al or Al alloy, first, a pellet (16) is formed from Ti powder and/or Zr powder (10), graphite powder (12) and Al or Al alloy powder (14), then the pellet is infiltrated with molten Al or Al alloy, and thereafter the pellet is heated up to 1000.degree.-1800.degree. C. in an inactive atmosphere, so that TiC particles and/or ZrC particles are generated in the pellet. Then the pellet is dissolved in a molten bath of Al or Al alloy.
    Type: Grant
    Filed: July 1, 1993
    Date of Patent: August 9, 1994
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventors: Tetsuya Nukami, Tetsuya Suganuma
  • Patent number: 5324366
    Abstract: A heat treat furnace system 20 for heat treating metal workpieces includes a rotary carburizing chamber 24 containing a carburizing atmosphere, a cooling chamber 40A or 40B adjacent the carburizing chamber 24, a gas barrier device 50 cooperating with the cooling chamber opening and the carburizing chamber outlet for impeding movement of atmosphere therethrough; and transfer mechanisms for operatively moving at least one selected workpiece from the carburizing chamber 24 to the cooling chamber 40A or 40B and vice versa, and from the cooling chamber 40B to the equalizing chamber 26 and vice versa. The carburizing chamber 24 has a circular rotatable hearth for supporting an array of workpieces, and an inlet for loading the workpieces into the carburizing chamber 24. The cooling chamber 40A or 40B also has means for providing a protective atmosphere within it.
    Type: Grant
    Filed: August 9, 1991
    Date of Patent: June 28, 1994
    Assignee: Caterpillar Inc.
    Inventors: Gary D. Keil, Loren D. Thompson, deceased
  • Patent number: 5294264
    Abstract: A method of nitriding a refractory-nitride forming metal or metalloid articles and composite articles. A consolidated metal or metalloid article or composite is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article or composite is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article or composite is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid or composite to an article or composite of refractory nitride. In addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.
    Type: Grant
    Filed: January 10, 1992
    Date of Patent: March 15, 1994
    Assignee: Martin Marietta Energy Systems, Inc.
    Inventors: Terry N. Tiegs, Cressie E. Holcombe, Norman L. Dykes, Ogbemi O. Omatete, Albert C. Young
  • Patent number: 5192485
    Abstract: A continuous annealing line for annealing a cold-rolled strip of a ultra-low-carbon steel comprising a heating furnace for heating the strip which is fed continuously, with or without a soaking furnace following the heating furnace, a cooling furnace in which the heated steel strip is cooled, and a carburizing/nitriding furnace disposed between the heating furnace or the soaking furnace and the cooling furnace. The carburizing/nitriding furnace may be divided into a plurality of zones, each of which is provided with control means for controlling the carburizing/nitriding atmosphere and carburizing/nitriding temperature in the zone. The continuous annealing line may further comprise a plurality of carburizing/nitriding furnaces and have an arrangement for conducting a switching between a mode in which the carburizing/nitriding furnace is used for carburizing/nitriding the steel strip and a mode in which the carburizing/cooling furnace is used for cooling the steel strip.
    Type: Grant
    Filed: July 30, 1991
    Date of Patent: March 9, 1993
    Assignee: Kawasaki Steel Corp.
    Inventors: Koshi Kuramoto, Tsuguhiko Nakagawa, Satoshi Shibuya, Takao Ogawa, Toshikazu Kaihara, Kusuo Furukawa
  • Patent number: 5154779
    Abstract: A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.
    Type: Grant
    Filed: February 18, 1992
    Date of Patent: October 13, 1992
    Assignee: Martin Marietta Energy Systems, Inc.
    Inventors: Cressie E. Holcombe, Norman L. Dykes, Terry N. Tiegs