With Addition Of Gas Patents (Class 75/512)
  • Patent number: 9732393
    Abstract: The current invention refers to a blowing spear (100) used in the primary refining process for obtainment of steel, developed in such a way to maintain the loading and blowing operational conditions, comprising at the base a copper nozzle (101) to which is welded in its extremity a tube (102), comprising yet a module (125) with cleaning output (103) and positioned above module (125) a steel tube (118) and on its upper extremity, the head (107) that comprises a cooling liquid inlet (115), a gases inlet (116) and a cooling liquid outlet (117), comprising yet the spear (100) in its interior the inner tube (122) responsible for the gas passage and the intermediate tube (123) responsible for the division between the cooling liquid inlet flow and its outlet passing mandatorily through the copper nozzle (101).
    Type: Grant
    Filed: July 8, 2013
    Date of Patent: August 15, 2017
    Assignee: LUMAR METALS LTDA.
    Inventor: Marcelo de Souza Lima Guerra
  • Patent number: 9109838
    Abstract: This invention relates to a gas blowing nozzle for blowing a gas to a molten metal in a furnace, the gas blowing nozzle including: a first nozzle section including a plurality of first narrow metal pipes having open furnace-side tips exposed to an inside of the furnace and being in the state of capable of blowing a gas to the molten metal in the furnace, a first surge tank communicated with the first narrow metal pipes, and a first refractory protecting the first narrow metal pipes and the first surge tank; and a second nozzle section including a plurality of second narrow metal pipes, a second surge tank communicated with the second narrow metal pipes, and a second refractory protecting the second narrow metal pipes and the second surge tank.
    Type: Grant
    Filed: June 23, 2011
    Date of Patent: August 18, 2015
    Assignee: SHINAGAWA REFRACTORIES CO., LTD.
    Inventor: Shinobu Imai
  • Publication number: 20140096648
    Abstract: A method for controlling A-shaped segregation of steel ingot. The method includes: 1) controlling a content of phosphorus in liquid steel at less than or equal to 0.005 wt. % upon tapping from an electric furnace, preventing steel slag from entering a ladle, controlling content of harmful elements at less than or equal to 100 ppm; and adding between 3 and 15 kg of calcium oxide and less than or equal to 0.5 kg of aluminum to each ton of the liquid steel; 2) pre-deoxidizing the liquid metal using vacuum carbon deoxidation; 3) de-sulfurizing, controlling content of oxygen, and controlling the content of sulfur in the liquid steel at less than or equal to 0.005 wt. %; and 4) performing vacuum degasification, controlling the total oxygen content at less than or equal to 15 ppm; and casting the steel in the presence of inert gas or in vacuum.
    Type: Application
    Filed: December 12, 2013
    Publication date: April 10, 2014
    Applicant: INSTITUTE OF METAL RESEARCH CHINESE ACADEMY OF SCIENCES
    Inventors: Dianzhong LI, Paixian FU, Hongwei LIU, Lijun XIA, Yiyi LI
  • Patent number: 8562713
    Abstract: A combined arc furnace, ladle metallurgical furnace and vacuum degassing system having the flexibility to produce at least non-vacuum arc remelt, vacuum arc remelt, vacuum oxygen decarburized non-vacuum arc remelt, and vacuum oxygen decarburized vacuum arc remelt steels from one off to continuous casting end uses in steady state or randomized order which utilizes only a minimum of energy attributable to preheating hot metal contacting components of the system followed by heat loss reduction of the components and use of a carryover heel in the arc furnace, in which the throughput of the system is limited solely by the melting capacity of the arc furnace.
    Type: Grant
    Filed: May 27, 2011
    Date of Patent: October 22, 2013
    Assignee: A. Finkl & Sons Co.
    Inventors: John A. Guliana, Guy A. Brada, Christian H. Ericksen, Bruce C. Liimatainen, Algirdas A. Underys
  • Patent number: 8523977
    Abstract: A method of desulfurizing steel including steps of forming a slag over a molten metal, drawing a vacuum to less than 5 torr over the slag and molten metal, stirring the molten metal and slag, and deoxidizing and desulfurizing the molten metal and slag to degas the steel reducing at least sulfur, nitrogen, oxygen, and hydrogen contents, and reducing activity of oxygen in the molten metal to less than 30 ppm. The method includes forming a slag composition after degassing the steel comprising CaO between about 50 and 70% by weight, SiO2 between about 20 and 28% by weight, CaF2 between about 5 and 15% by weight, MgO not more than 8% by weight, Al2O3 not more than 1% by weight, and a combination of FeO+MnO not more than 2% by weight, where the sum of CaO+CaF2+SiO2+MgO is at least 85% by weight.
    Type: Grant
    Filed: May 12, 2011
    Date of Patent: September 3, 2013
    Assignee: Nucor Corporation
    Inventors: Dhiren Panda, Neal Ross, Gary McQuillis, Jerome Jenkins
  • Patent number: 8277537
    Abstract: A method of manufacturing a ferritic stainless steel containing an ultra low level of carbon concentration in molten steel within time shorter than existing technology by controlling content, appropriate composition, and liquid-state fraction, etc., of Cr2 O3 in slag to maximize vacuum decarburization refining efficiency, the method comprising: tapping molten steel to a ladle in a non-deoxidized state after pre-decarburization and denitrification in an ARGON OXYGEN DECARBURIZATION refining furnace and then removing non-deoxidized slag; placing the ladle in a vacuum furnace, reducing pressure and then blowing-in oxygen gas from the upper of the molten steel through a lance; creating Al2 O3 by injecting Al at point of time of beginning of oxygen blowing; forming CaO—Al2 O3 —Cr2 O3 —MgO-based slag by injecting calcium oxide at point of time of completion of the oxygen blowing; and supplying inert gas through a porous plug on a bottom of the ladle.
    Type: Grant
    Filed: September 30, 2008
    Date of Patent: October 2, 2012
    Assignee: Posco
    Inventors: Joo Hyun Park, Sun Min Byun, Sang Beom Lee, Min Oh Suk, Hee Ho Lee
  • Patent number: 8262767
    Abstract: A method of producing steel for a steel pipe excellent in sour-resistance performance comprises controlling the amount of Ca addition charged into a molten steel in a ladle according to a N content in the molten steel prior to Ca addition. Non-metallic inclusions in the steel are mainly composed of Ca, Al, 0 and S, and a CaO content in the inclusions is in the range of 30 to 80%, the ratio of the N content in the steel to the CaO content in the inclusions satisfying equation (1), and a CaS content in the inclusions satisfies equation (2), 0.28?[N]/(% CaO)?2.0??(1) (% CaS)?25%??(2) where [N] represents the mass content (ppm) of N in the steel, (% CaO) represents the mass content (%) of CaO in the inclusions, and (% CaS) represents the mass content (%) of CaS in the inclusions.
    Type: Grant
    Filed: May 9, 2011
    Date of Patent: September 11, 2012
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Mitsuhiro Numata, Shingo Takeuchi, Tomohiko Omura
  • Patent number: 7959709
    Abstract: A method of producing steel pipe excellent in sour-resistance performance, uses comprises controlling the amount of Ca addition charged into molten steel in a ladle according to a N content in the molten steel prior to Ca addition. As a result of the controlling step, a CaO content in the inclusions is in the range of 30 to 80%, the ratio of the N content in the steel to the CaO content in the inclusions satisfies the relation expressed by equation (1), and a CaS content in the inclusions satisfies the relation expressed by equation (2). 0.28?[N]/(% CaO)?2.0??(1) (% CaS)?25%??(2) where [N] represents the mass content (ppm) of N in the steel, (% CaO) represents the mass content (%) of CaO in the inclusions, and (% CaS) represents the mass content (%) of CaS in the inclusions.
    Type: Grant
    Filed: December 2, 2009
    Date of Patent: June 14, 2011
    Assignee: Sumitomo Metal Industries, Ltd.
    Inventors: Mitsuhiro Numata, Shingo Takeuchi, Tomohiko Omura
  • Patent number: 7901482
    Abstract: Molten steel is refined in an electric furnace by using iron scrap as a main iron source, and is tapped into a separate refining vessel. Thereafter, metallic-Al containing material and CaO are added onto a bath surface of the molten steel, and an oxygen containing gas is supplied to the molten steel. Thereby, a nitrogen-removal reaction utilizing an AlN formation reaction is caused to proceed. Consequently, even in the case of molten steel having a low carbon content, a low-nitrogen steel can be refined and produced at low costs.
    Type: Grant
    Filed: February 6, 2007
    Date of Patent: March 8, 2011
    Assignee: JFE Steel Corporation
    Inventors: Chikashi Tada, Chitoshi Matsumura
  • Patent number: 7481964
    Abstract: A system for producing a metal foam comprises a bath containing a molten metal, a rotating shaft or impeller extending through the base of the bath into, and submerged in the molten metal, and a gas discharge nozzle provided on the submerged end of the shaft. The opposite end of the shaft is connected to a gas supply line and the shaft is rotated with a motor. A seal is provided at the opening in the base of the bath for preventing leakage of the molten metal there-through.
    Type: Grant
    Filed: March 3, 2003
    Date of Patent: January 27, 2009
    Assignee: CYMAT Corp.
    Inventors: Scott Nichol, Richard G. Manley
  • Patent number: 6843826
    Abstract: A vacuum treatment of cast metal in liquid form employing the steps of: introducing the cast metal in liquid form into a metallurgic ladle; filling the ladle until a guard height ranging between 0.4 and 0.6 m is reached; and treating the metal while bringing the atmosphere above the ladle under vacuum, and simultaneously stirring the cast metal by injecting helium into the base of the ladle during part of or the whole treatment.
    Type: Grant
    Filed: March 27, 2001
    Date of Patent: January 18, 2005
    Assignee: Usinor
    Inventors: François Stouvenot, Marc Burty, Jean-François Domgin, Pascal Gardin, Dominique Viale, Raymond Reitz, Frédéric Leclercq
  • Publication number: 20040245682
    Abstract: A refining method and refining apparatus, able to shorten the time required for refining and reduce the refining costs in decarburization refining of a chromium-contained molten steel, which refining method for chromium-contained molten steel etc. performing decarburization refining by blowing a gas containing oxygen gas into a chromium-contained molten steel under a vacuum or atmospheric pressure and vacuum, said refining method for a chromium-contained molten steel etc. characterized by having a first step for blowing oxygen gas while making the inside of the vessel a pressure of a range of 400 Torr (53 kPa) to atmospheric pressure, a second step for blowing oxygen gas while evacuating the inside of the vessel to 250 to 400 Torr (33 to 53 kPa), and third step for blowing gas while evacuating the inside of the vessel to not more than 250 Torr (33 kPa).
    Type: Application
    Filed: March 22, 2004
    Publication date: December 9, 2004
    Inventors: Kosuke Yamashita, Ryuji Nakao, Tomoaki Tanaka, Masao Igarashi, Koichiro Yoshino, Makoto Sumi
  • Patent number: 6764528
    Abstract: A method of producing a high nitrogen, ultra low carbon steel suitable to rolling material for use in cold rolled steel sheets having excellent age hardening property by an age hardening treatment after forming by working, with no defects in slabs or steel sheets, reliably, at a reduced cost and with a high productivity is proposed. The method for producing a rolling material for use in ultra low carbon steel sheets at: C≦0.0050 mass % comprises; applying primary decarburization refining to molten iron from a blast furnace, then controlling the composition in the molten steel after primary decarburization refining to a range satisfying the following relation: [mass % N]−0.15[mass % C]≧0.0060,  subsequently conducting secondary decarburization refining to a ultra low carbon concentration region while suppressing denitridation using a vacuum degassing facility, then conducting deoxidation by Al and, further, controlling the composition.
    Type: Grant
    Filed: August 8, 2002
    Date of Patent: July 20, 2004
    Assignee: JFE Steel Corporation
    Inventors: Seiji Nabeshima, Shuji Takeuchi, Hisashi Ogawa, Yuki Nabeshima, Yasuyuki Masumoto
  • Publication number: 20040035248
    Abstract: A vacuum treatment of cast metal in liquid form employing the steps of: introducing the cast metal in liquid form into a metallurgic ladle; filling the ladle until a guard height ranging between 0.4 and 0.6 m is reached; and treating the metal while bringing the atmosphere above the ladle under vacuum, and simultaneously stirring the cast metal by injecting helium into the base of the ladle during part of or the whole treatment.
    Type: Application
    Filed: December 11, 2002
    Publication date: February 26, 2004
    Inventors: Francois Stouvenot, Marc Burty, Jean-Francois Domgin, Pascal Gardin, Dominique Viale, Raymond Reitz, Frederic Leclerco
  • Patent number: 6666902
    Abstract: The present invention provides a lade refining apparatus capable of suppressing skull deposition in a vacuum/decompression chamber and performing molten steel agitation, slag reforming and degassing efficiently, and a ladle refining method using the apparatus. The apparatus includes a vacuum/decompression chamber directly coupled to a top of a ladle, and is designed to have inert gas blown into the ladle for agitation of molten steel in the ladle. An inner diameter of a shaft of the vacuum/decompression chamber is not larger than an inner diameter of a top end of the ladle, but not smaller than a projected diameter of a bulging portion of a molten steel surface formed by the gas blown into the ladle.
    Type: Grant
    Filed: December 14, 2001
    Date of Patent: December 23, 2003
    Assignee: Nippon Steel Corporation
    Inventors: Hideaki Kimura, Atsushi Ishikawa, Hiromi Ishii, Masayuki Arai, Jun Aoki
  • Patent number: 6358299
    Abstract: A VOD refining method for fast-cut stainless steel containing sulphur includes a step of VOD refining process, another step of reduction and residue producing and ferrous sulphide adding process, another step of micro-adjusting control process, and a last step of taking out the steel. The feature is to add 0.001 wt %-0.01 wt % CaO and 0.001 wt %-0.005 wt % MgO in the steel liquid during the micro-adjusting control process, in order to elevate sulphur absorption and enhance the aggregate sulphur recycling percentage to more than 85%.
    Type: Grant
    Filed: November 19, 1999
    Date of Patent: March 19, 2002
    Assignee: Walsin Lihwa Corp.
    Inventor: Yu-Sheng Wei
  • Patent number: 6235084
    Abstract: The invention relates to a process for decarburizing a steel melt in a closed metallurgical vessel that is connected to a vacuum unit which includes reducing pressure in the vessel to below 100 mbar, introducing replenishment oxygen to implement the removal of carbon, introducing a predetermined additional amount of oxygen, and introducing a combustible metallic substance with the additional amount of oxygen. The invention also relates to an apparatus for performing the above process including the closable vessel, measurement elements for determining melt temperature and pressure, and a controller for controlling the amount of additional oxygen and combustible metallic substance in response to the melt temperature and pressure.
    Type: Grant
    Filed: July 24, 1998
    Date of Patent: May 22, 2001
    Assignee: Mannesmann AG
    Inventors: Horst-Dieter Schöler, Volker Wiegmann, Rainer Dittrich, Frank Haers, Leo Peeters
  • Patent number: 6190435
    Abstract: A method for vacuum decarburization refining of a molten steel includes providing a vacuum tank having a one-legged, straight barrel snorkel as a lower portion of the vacuum tank. The a degree of vacuum in the vacuum tank is regulated at a high carbon concentration region to a value in a range of −35 to −20 in terms of G defined by the following equation (1): G=5.96×10−3×T×ln(P/Pco)  (1), wherein Pco=760{10(−13800/T+8.75)}×(% C)/(% Cr)  (2), and wherein P<760, T represents molten steel temperature, K, and P represents the degree of vacuum in the vacuum tank, Torr.
    Type: Grant
    Filed: August 17, 1998
    Date of Patent: February 20, 2001
    Assignee: Nippon Steel Corporation
    Inventors: Kenichiro Miyamoto, Katsuhiko Kato, Akio Shinkai, Takayuki Kaneyasu, Shinya Kitamura, Hiroyuki Ishimatsu, Hiroshi Sugano, Keiichi Katahira, Ryuzou Hayakawa
  • Patent number: 6110300
    Abstract: A tool for glass molding operations, particularly television tubes, having high oxidation resistance so that ice imperfections on a formed workpiece are eliminated or drastically reduced, said tool having the following approximate composition by weight percent: C 0.23-0.38, Mn 0.40-1.00, P 0.040 max, S 0.030 max, Si 0.00-1.20, Ni 1.0-3.0, Cr 14.0-20.0, Mo 0.25-1.00, V 0.10 max, Cu 0.50-1.50, Al 0.50-1.
    Type: Grant
    Filed: April 7, 1997
    Date of Patent: August 29, 2000
    Assignee: A. Finkl & Sons Co.
    Inventors: Guy A. Brada, Algirdas A. Underys, Jesse Adamson
  • Patent number: 6042633
    Abstract: A method for after combustion of reaction gases resulting from the decarburization of liquid steel in reaction vessels under vacuum includes the steps of arranging a blow-in opening within a refractory lining of a reaction vessel and introducing an air stream, comprised of hot air of a temperature between 800.degree. C. to 1400.degree. C., counter to the flow direction of the reaction gases via the blow-in opening into the reaction vessel. A device for performing after combustion of reaction gases resulting from the decarburization of liquid steel in a reaction vessel under vacuum includes a generator, connected to the reaction vessel, for producing hot air. The generator contains a bulk of balls for heating the air guided through the bulk of balls and subsequently introduced into the reaction vessel. The bulk of balls consists of a refractory material and is heated by heat energy.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: March 28, 2000
    Assignee: Technometal Gesellschaft fur Metalltechnologie mbH
    Inventors: Karl Brotzmann, Heinz Holtermann
  • Patent number: 5931985
    Abstract: A process for blowing oxygen-containing gas, with and without solid material, on a metal melt in a metallurgical vessel, a process for generating a burner flame and corresponding devices. The inventive process and lance suitable for such process provides, without structural conversion and by a simple design, various different process steps in the treatment of metal melts in a metallurgical vessel while increasing the insertion rates of the individual media. This is accomplished using a multifunctional lance in which the process of blowing oxygen with and without solids, and the generation of a burner flame may be performed independently from one another. The individual supply lines are connected in a corresponding manner depending on the respective process step. In the process for blowing oxygen-containing gas, vibrations are excited in the gas flow in a relatively simple manner.
    Type: Grant
    Filed: May 19, 1997
    Date of Patent: August 3, 1999
    Assignee: Mannesmann Aktiengesellschaft
    Inventors: Horst-Dieter Schoeler, Ulrich Meyer, Anatoly Sizov
  • Patent number: 5827376
    Abstract: A plastic industry prototype mold and steel therefor having machining speed and weldability characteristics competitive with aluminum alloys, and a method of manufacture thereof, said composition containing C 0.05-0.35, Mn .50-1.50, P 0.025.times., S 0.100.times., Si 0.50.times., Ni 0.35-0.75, Mo 0.30-0.70, Cu 0.75-1.50, Al 0.20.times. and Fe bal.
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: October 27, 1998
    Assignee: A. Finkl & Sons Co.
    Inventor: Algirdas A. Underys
  • Patent number: 5720829
    Abstract: A maraging type magnetic hot work implement, such as a forging die, or a tool, such as a turbine blade, having Ni.sub.3 Mo, Ni.sub.3 Al and, preferably, Ni.sub.3 Ti strengthening precipitates dispersed uniformly, and being substantially Co free, said product having the following approximate composition by weight percent:______________________________________ C less than .20 Mn .80 max P .015 max S .010 max Si .15-.35 Ni 6.00-16.00 Cr 6.00-14.00 Mo 2.00-6.00 V 0.3-.15 Ti 0.00-4.00 Al .20-8.00 Fe balance together with incidental impurities and other elements not significantly adversely affecting performance ______________________________________and methods of manufacture thereof.
    Type: Grant
    Filed: February 2, 1996
    Date of Patent: February 24, 1998
    Assignee: A. Finkl & Sons Co.
    Inventors: Charles W. Finkl, Guy A. Brada, Algirdas A. Underys
  • Patent number: 5693120
    Abstract: In a vacuum degassing and decarburization treatment, the present invention uses a CO.sub.2 gas as a recirculating gas and as a stirring gas without inviting stoppage of decarburization and an increase in the carbon concentration and moreover, without an increase in the amount of addition of an alloy, and can reduce the gas cost. The present invention provides a production method for a low carbon molten steel which comprises blowing a CO.sub.2 gas from the start of degassing treatment till the carbon concentration of the molten steel reaches 50 ppm in vacuum degassing and decarburization treatment of the molten steel, and thereafter blowing an Ar gas.
    Type: Grant
    Filed: December 1, 1995
    Date of Patent: December 2, 1997
    Assignee: Nippon Steel Corporation
    Inventors: Yasuo Obana, Koichi Endoh, Makoto Moriguchi, Toshihiko Kaku, Shigenori Yagura, Fumio Hayashi
  • Patent number: 5571307
    Abstract: The invention relates to a process and a device for blowing oxygen over a metal melt under a vacuum. The oxygen is to be applied over a large surface with a large intermediate phase area while avoiding overcooling in the metal bath by simple, easily maintained structural means. The flow of oxygen in the lance is accelerated and compressed into plug-shaped oxygen pulses, which leave the lance in succession and which form an oxygen bell over the vacuum above the metal melt, having an oxygen casing and an oxygen core, the core moving at a speed similar to that of the casing. At the base of the wall 41 of the blowing lance 40 there is an annular nozzle 42. At a distance behind the annular nozzle 42 in the direction of flow of the oxygen there is a blind tube 44 forming a fan-shaped compartment 43. Between the bottom 46 of the blind tube 44 and the head of the blowing lance 40 there is a pre-nozzle chamber 48 and in the head of the blowing lance 40 there is at least one base nozzle 50 directed toward the melt.
    Type: Grant
    Filed: February 10, 1995
    Date of Patent: November 5, 1996
    Assignee: Mannesmann Aktiengesellschaft
    Inventors: Anatoly Sizov, Horst-Dieter Scholer, Ulrich Meyer
  • Patent number: 5547489
    Abstract: In the production of stainless steel it is aimed at to depress the highest temperature reaching during refining the molten steel with keeping the necessary tapping temperature so as to prolong the life of refractory materials of the refining furnace. After carrying out decarburization treatment under atmospheric pressure in a refining furnace by blowing an oxygen-containing gas into molten steel, further decarburization of the molten steel and reduction of chromium oxides is carried out under stirring by blowing a non-oxidizing gas under a reduced pressure, and then, reducing agent is charged into the furnace to reduce chromium oxides under keeping the reduced pressure.
    Type: Grant
    Filed: May 22, 1995
    Date of Patent: August 20, 1996
    Assignee: Daido Tokushuko Kabushiki Kaisha
    Inventors: Yoshio Inagaki, Motoshi Shinkai, Masahide Tsuno, Akihiro Nagatani
  • Patent number: 5468280
    Abstract: A method, for the conveyance of molten metal from one place to another, in a high-temperature molten metal pool in a metal-melting furnace or out of said molten metal pool, employing an at least partially-inclined elongated conveying conduit and gas feed means for feeding inert gas into the lower end of the conveying conduit and thereby inducing a flow of molten metal in and through said conveying conduit, is disclosed, along with suitable apparatus for carrying out the said method wherein the parts or elements coming into contact with the high-temperature molten metal pool are of a suitable refractory material. According to the present invention, the inert gas is fed into the conveying conduit at a supersonic velocity, thereby simultaneously effecting a degassing of the molten metal while it is being conveyed.
    Type: Grant
    Filed: April 19, 1993
    Date of Patent: November 21, 1995
    Assignee: Premelt Pump, Inc.
    Inventor: Larry D. Areaux
  • Patent number: 5417739
    Abstract: A method of making stabilized ultra-low carbon steel having a high nitrogen content for enameling applications. The preferred method involves two phases. The first phase occurs in the basic oxygen furnace wherein nitrogen gas is combined with oxygen gas and blown into the melt through the oxygen lance. After the oxygen blow the carbon content of the melt is approximately 0.03% and the nitrogen content is at least about 0.016 to 0.020%. In the second phase the melt is introduced to a vacuum circulation decarburizer where the carbon content of the steel is reduced to ultra low levels on the order of 0.005%. The nitrogen content is maintained at a level of at least about 0.01% by introducing nitrogen gas into the vacuum decarburization vessel as the lift gas through inert gas tuyeres.
    Type: Grant
    Filed: December 30, 1993
    Date of Patent: May 23, 1995
    Assignee: LTV Steel Company, Inc.
    Inventors: Richard R. Watkins, Robert Blossey, Gregory Wotell
  • Patent number: 5413623
    Abstract: Molten steel is efficiently vacuum treated in a vacuum treatment vessel provided with a top blow lance capable of injecting oxygen and a gaseous fuel at desired flow rates, respectively, into the molten steel. The blow lance is provided on the top of the vacuum treatment vessel and is supported so as to be freely vertically movable. By spacing the lower end of the top blow lance not more than 2 m from the surface of the molten steel bath and injecting only oxygen onto the molten steel, and spacing the lower end of the top blow lance 1.0 m or more from the surface of the molten steel bath and injecting both oxygen and a gaseous fuel gas onto the molten steel, the temperature of the molten steel is prevented from decreasing during the vacuum treatment and the molten steel is so prevented from depositing on the inside wall of the vacuum treatment vessel.
    Type: Grant
    Filed: August 25, 1993
    Date of Patent: May 9, 1995
    Assignee: Nippon Steel Corporation
    Inventors: Kazuo Oonuki, Teruyoshi Hiraoka, Hiroshi Nagahama, Kazuhisa Fukuda, Akira Nobumoto, Takahiro Isono, Atsumi Yamada, Hiroki Gofuku
  • Patent number: 5397378
    Abstract: A method, for the conveyance of molten metal from one place to another, in a high-temperature molten metal pool in a metal-melting furnace or out of said molten metal pool, employing an at least partially-inclined elongated conveying conduit and gas feed means for feeding inert gas into the lower end of the conveying conduit and thereby inducing a flow of molten metal in and through said conveying conduit, is disclosed, along with suitable apparatus for carrying out the said method wherein the parts or elements coming into contact with the high-temperature molten metal pool are of a suitable refractory material. According to the present invention, the molten metal is alloyed simultaneously with its conveyance, the same inert gas being employed for both conveying the molten metal and for entrainment of the alloying metal.
    Type: Grant
    Filed: April 19, 1993
    Date of Patent: March 14, 1995
    Assignee: Premelt Pump, Inc.
    Inventor: Larry D. Areaux
  • Patent number: 5332417
    Abstract: Method for decarburisation of steel in a vacuum treatment chamber consisting of an upper part (4) in the shape of a bell, of an intermediate ring (5) and of a lower part (6) in which the bath of metal to be treated (2) is located and which is equipped with two legs (7, 8) which are immersed in the steel ladle (9) containing all the metal (10) to be treated, characterised in that oxygen is blown horizontally over the bath of metal to be treated (2), at the level of the intermediate ring (5), substantially at the centre of the latter.Vacuum steel-treatment chamber in which at least two horizontal tuyeres (11, 12) are provided in the intermediate ring (5) of the said chamber, substantially in the centre of the latter.
    Type: Grant
    Filed: March 11, 1993
    Date of Patent: July 26, 1994
    Assignee: Sollac
    Inventor: Bernard Bauvois
  • Patent number: 5324342
    Abstract: Mixed gas of nonoxidizing gas and oxygen is blown into molten chrome steel in a vessel. The molten chrome steel is stirred by the gas and is decarbonized by the oxygen in the gas while being stirred. After the carbon potential in the molten chrome steel has been lowered, the pressure inside the vessel is reduced and the nonoxidizing gas alone is blown as the gas. Bubbles of the gas blown into the molten chrome steel become large on account of reduced pressure and exhibit sufficient stirring function. Consequently, the molten chrome steel is effectively stirred and the decarbonizing reaction is prompted.
    Type: Grant
    Filed: April 9, 1992
    Date of Patent: June 28, 1994
    Assignee: Daidotokushuko Kabushikikaisha
    Inventors: Hiroshi Mori, Motoshi Shinkai, Junichi Tsubokura
  • Patent number: 5304231
    Abstract: Disclosed is a method of refining of a high purity steel capable of effectively lowering impurities in molten steel into respective ultra-low ranges. In secondary refining for molten steel after a molten iron prerefining process and a converting process, a reducing agent and a flux are added on the bath surface within a ladle containing the molten steel decarburized in a converter so that the composition of slag on the bath surface is adjusted in such a manner that the total concentration of FeO and MnO becomes 5 wt % or less, and subsequently, impurities in the molten steel are effectively lowered into respective ultra-low ranges using a RH vacuum degassing unit.
    Type: Grant
    Filed: December 18, 1992
    Date of Patent: April 19, 1994
    Assignee: Kawasaki Steel Corporation
    Inventors: Yoshiei Kato, Tadasu Kirihara, Seiji Taguchi, Tetsuya Fujii, Shigeru Omiya, Masahito Suito
  • Patent number: 5221326
    Abstract: A method of producing an ultra-low-carbon steel by conducting vacuum-decarburization of a molten steel by means of a vacuum degasifier of the type having recirculation pipes and a vacuum chamber. When the carbon content of the molten steel has come down to a level of 50 ppm or less, hydrogen gas is introduced together with an inert gas into the molten steel either by directly injecting a hydrogen-containing gas into the molten steel in the vacuum chamber through a tuyere provided in the wall of the vacuum chamber or by blowing the hydrogen-containing gas onto the surface of the molten steel in the vacuum chamber through a lance provided in the vacuum chamber. In order to enhance the effect produced by the method of the present invention, it is possible to take an additional measure such as blowing of hydrogen gas through a tuyere provided in the wall of the recirculation pipe or injection of hydrogen or hydrogen-containing gas through an injection lance immersed in the molten steel held in, a ladle.
    Type: Grant
    Filed: May 15, 1991
    Date of Patent: June 22, 1993
    Assignee: Kawasaki Steel Corporation
    Inventors: Koji Yamaguchi, Yasuo Kishimoto, Toshikazu Sakuraya, Masaru Washio, Kazuhisa Hamagami, Hiroshi Nishikawa
  • Patent number: 5152831
    Abstract: A method of producing an ultra-low-carbon steel by using a vacuum degasser on a molten steel has the steps of conducting vacuum decarburization to attain a predetermined level of carbon content, e.g., 25 ppm or below, in the molten steel while progressively reducing the pressure in said vacuum degasser, conducting addition of hydrogen in which hydrogen is dissolved in said molten steel while said pressure is temporarily elevated to 20 Torr or above, and conducting final decarburization after reducing said pressure to 2 Torr or below. The addition of hydrogen may be conducted to meet the following conditions:[H].gtoreq.{([C]-[C]final)/5}+4wherein [H] represents the hydrogen content (ppm) in said molten steel in the state after the addition of hydrogen, [C] represents the carbon content (ppm) in the molten steel in the state after the addition of hydrogen, and [C] final represents the final carbon content (ppm) to be obtained.
    Type: Grant
    Filed: September 30, 1991
    Date of Patent: October 6, 1992
    Assignee: Kawasaki Steel Corporation
    Inventors: Koji Yamaguchi, Yasuo Kishimoto, Toshikazu Sakuraya, Masaru Washio, Kazuhisa Hamagami, Hiroshi Nishikawa
  • Patent number: 5139568
    Abstract: A process for the continuous production of an iron-carbon alloy utilizing an enclosed reactor (10) capable of limiting the ingress and egress of atmospheric gases and gas reaction products respectively. A solid mineral material (20) containing iron carbide and at least trace amounts of iron oxide, and having a weight ratio of at least about 2:1 or greater, is fed into a molten bath (12) of metallic material in the reactor (10). The molten metallic material is simultaneously reacted with oxygen at a temperature sufficient to generate carbon monoxide as a reaction product. The oxygen is preferably injected into the molten metallic material to facilitate the reaction of the oxygen with carbon from the iron carbide to form the carbon monoxide. The carbon monoxide subsequently enters a vapor space (17) of the reactor (10) above the molten bath (12), and further reacts with oxygen to generate carbon dioxide and heat.
    Type: Grant
    Filed: October 3, 1991
    Date of Patent: August 18, 1992
    Assignee: Cargill, Incorporated
    Inventor: Gordon W. Geiger
  • Patent number: 5091000
    Abstract: Molten metal is put under pressure of up to 10 atmospheres in a covered ladle and a gas soluble in the metal is bubbled through the melt. Some gas goes into solution, while the remainder rises in bubbles and brings inclusions suspended in the molten metal up to the surface. Then the pressure is lowered, after which gas comes out of the solution in fine bubbles which also bring impurity inclusions up to the surface. In another method molten steel is refined at pressures not exceeding atmospheric pressure in a covered ladle equipped for evacuation and equipped for bubbling gas through the molten steel bath. Bubbling followed by pressure reduction can then be performed to form two stages of cleaning. Heat may be added for compensating the cooling effect of gas expansion.
    Type: Grant
    Filed: April 30, 1990
    Date of Patent: February 25, 1992
    Assignee: NKK Corporation
    Inventors: Toshio Ishii, Yutaka Okubo, Shuzo Fukuda, Yoshihiko Kawai, Shunichi Sugiyama, Yoshiteru Kikuchi, Hidetoshi Matsuno
  • Patent number: 5047081
    Abstract: The present invention relates to a method which may decarburize high Cr molten metal for a short period of time under an atmospheric pressure, while checking loss of Cr by its oxidation. A basic feature of the invention is to blow from the furnace top lance a decarburizing O.sub.2 diluted by an inert gas into the high Cr molten metal supported in a container as well as blow the inert gas from bottom tuyeres so as to forcibly agitate the molten metal. Another feature of the invention is to control a slag amount during the above decarburizing blowing so as to check the Cr oxidation loss. A further object of the invention is to carry out a denitrification in the above decarburization, thereby to produce low N molten metal while checking the loss by Cr oxidation.
    Type: Grant
    Filed: April 5, 1989
    Date of Patent: September 10, 1991
    Assignee: NKK Corporation
    Inventors: Haruyoshi Tanabe, Masahiro Kawakami, Kenji Takahashi, Katsuhiro Iwasaki, Shigeru Inoue
  • Patent number: 4979983
    Abstract: A process of degassing and decarbonizing is directed to a process for performing vacuum degassing non-deoxidized or slightly deoxidized molten steel utilizing RH process or DH process. The process includes blowing of oxygen or oxygen containing gas toward the surface of the molten steel in a vacuum chamber for promoting decarbonizing reaction. The process further includes a step of combustioning of CO gas in the vicinity of the surface of the molten metal at a timing, in which concentration of (CO+CO.sub.2) in an exhaust gas is higher than or equal to 5% and a ratio of CO.sub.2 versus (CO+CO.sub.2) in the exhaust gas is approximately 30%. Heat generated by combustioning of CO gas is utilized for compensating temperature drop of the molten steel.
    Type: Grant
    Filed: June 21, 1989
    Date of Patent: December 25, 1990
    Assignee: Kawasaki Steel Corporation
    Inventors: Hiroshi Nishikawa, Kyoichi Kameyama, Ryuichi Asaho
  • Patent number: 4950324
    Abstract: This invention relates to a new method for the post melting treatment of molten steel in all, or nearly all, of the post melting systems in use at this time to lower the oxygen, hydrogen, and, to some extent, the nitrogen content thereof, and carry out the other purposes for which such systems are used including temperature and chemical homogenization continuous casting, piggy backing and other post melting treatment systems in use at this time in a manner which is less capital intensive, easier to operate and simpler in construction and operation than any of the basic systems, and apparatus therefor.
    Type: Grant
    Filed: January 24, 1989
    Date of Patent: August 21, 1990
    Assignee: A. Finkl & Sons Co.
    Inventors: Charles W. Finkl, Bruce Liimatainen, Herbert S. Philbrick, Jr.
  • Patent number: 4891064
    Abstract: A method of melting an iron-containing cold material and simultaneously obtaining a low phosphorous and high carbon molten iron while maintaining a high post combustion rate, comprising the steps of: preparing a converter having a lance for top-blowing oxygen, and a bottom-blowing triple pipe nozzle disposed at a bottom of the converter which nozzle is provided with an inner pipe, an intermediate pipe and an outer pipe; supplying the iron-containing cold material into the converter in which a hot heel exists; introducing into the converter all of a carbonaceous material together with a non-oxidizing gas through the inner pipe of the triple pipe nozzle, oxygen through a space defined between the inner pipe and the intermediate pipe, and a non-oxidizing cooling gas through another space defined between the intermediate pipe and the outer pipe, and additional oxygen through the oxygen top-blowing lance so that the cold material is melted into a molten iron under an existence of slag; maintaining both the content
    Type: Grant
    Filed: February 6, 1989
    Date of Patent: January 2, 1990
    Assignee: Nippon Steel Corporation
    Inventors: Kazushige Umezawa, Tatsuro Kuwabara, Tetsuya Oh-hara, Tsuzuru Nuibe, Kousaku Ozawa
  • Patent number: 4818281
    Abstract: A method of melting steel in an oxygen converter from solid metal iron-bearing materials includes the steps of loading these materials and their subsequent heating up to their melting through burning hydrocarbon and solid carbon-containing fuels in an oxygen-containing gas. Then, when the temperature of the melt is 1525.degree.-1580.degree. C. the oxidizing slag is removed from its surface and thereafter a solid iron is loaded into the bath in an amount of 2-5% of the original quantity of the solid metal iron-bearing materials.
    Type: Grant
    Filed: December 1, 1987
    Date of Patent: April 4, 1989
    Assignee: Nauchno-Proizvodstvennoe Obiedinenie "Tulachermet"
    Inventors: Gennady S. Kolganov, Stanislav S. Volkov, Jury A. Rudnev, Vladimir G. Mizin, Evgeny N. Ivashina
  • Patent number: 4772318
    Abstract: In a process for the production of steel from scrap in a refining vessel having feed nozzles below the surface of the steel bath and top-blowing devices and in which carbonaceous solid fuel and oxygen-containing gases are used as reagents, the same reagents are used to supply heat to the scrap and to the melt in the refining vessel and the resulting gaseous reaction products are after-burned with preheated air.
    Type: Grant
    Filed: March 4, 1987
    Date of Patent: September 20, 1988
    Assignee: Klockner CRA Technologie GmbH
    Inventors: Karl Brotzmann, Richard E. Turner, deceased
  • Patent number: 4761178
    Abstract: The temperature of molten steel in a ladle is raised to a predetermined level by introducing a plurality of oxygen containing gas streams beneath the surface of molten steel and introducing a predetermined quantity of an oxidizable fuel, such as aluminum or silicon, into the molten steel.
    Type: Grant
    Filed: August 24, 1987
    Date of Patent: August 2, 1988
    Assignee: Bethlehem Steel Corporation
    Inventors: Neal R. Griffing, Marvin H. Bayerwitz, Philip D. Stelts
  • Patent number: 4701216
    Abstract: The invention provides a method of melting and superheating ferrous material comprising the steps of charging a vessel with ferrous material and injecting into the vessel coal and oxygen in such ratios as to combust the coal to provide adequate heat for the melting of the ferrous material and to provide residual carbon in the melt to superheat the melt upon oxidation of the carbon.
    Type: Grant
    Filed: June 20, 1986
    Date of Patent: October 20, 1987
    Assignee: British Steel Corporation
    Inventors: Gene D. Spenceley, Brian C. Welbourn
  • Patent number: 4659375
    Abstract: A method of heating gases for combustion, operating turbines, and heating of a material and the like comprises the steps of providing a melt deposited in a vessel including two vessel elements and selected from the group consisting of a metal, a slag which is a mixture of metal oxides and nonmetal oxides, and a metal and a slag, supplying coal, air, fluxes and hot flue gases into the melt, passing the flue gases leaving the melt through a gas heater, passing a gas to be heated through one of the vessel elements, circulating the melt between the vessel elements, and supplying the gas which has been heated during passing through the one vessel element, to a gas consumer.
    Type: Grant
    Filed: December 31, 1985
    Date of Patent: April 21, 1987
    Inventor: Ernest S. Geskin
  • Patent number: 4643766
    Abstract: An improved two phase basic steel refining process for phosphoric pig iron is described which comprises forming a steel having a phosphorus content of not greater than 0.
    Type: Grant
    Filed: March 18, 1986
    Date of Patent: February 17, 1987
    Assignees: 501 Societe Lorraine de Laminage & Continu -Sollac-, 502 Unimetal
    Inventor: Roger Kieger
  • Patent number: 4615730
    Abstract: A method for refining a molten metal bath is provided including introducing a refining gas containing substantially a combination of oxygen and nitrogen to the molten bath to reduce the carbon content of the bath to a selected level; thereafter an inert gas, such as argon, is introduced to the molten bath from a lance adapted to direct the inert gas onto or beneath the bath surface, whereby the inert gas serves to efficiently remove nitrogen from the bath.
    Type: Grant
    Filed: April 30, 1985
    Date of Patent: October 7, 1986
    Assignee: Allegheny Ludlum Steel Corporation
    Inventor: Joseph W. Tommaney
  • Patent number: 4585475
    Abstract: Oily mill scale recovered from steel manufacturing operations downstream of a refining stage for molten steel is recycled to the refining stage. Coarse particles of mill scale are removed in a pre-screening operation, the mill scale is mixed and blended with a binder, and the mixture is agglomerated into shapes, such as briquettes, using external mechanical pressure. The agglomerated shapes are introduced into molten metal containing excessive carbon, where the shapes act as a coolant and the iron oxide in the mill scale reacts with some of the carbon. The oily mill scale is neither deoiled nor ground more finely prior to introduction into the molten metal, and all processing of the mill scale is conducted under ambient conditions of temperature, pressure and atmosphere. The agglomerated shapes may be aged prior to introduction into the molten metal.
    Type: Grant
    Filed: October 23, 1981
    Date of Patent: April 29, 1986
    Assignee: Inland Steel Company
    Inventor: Donald R. Fosnacht
  • Patent number: 4561886
    Abstract: A method of and an apparatus for heating, melting and production of gaseous fuel include supplying air, coal, steam into a melt. The melt contains elements readily oxidized by air. These elements produce oxides readily reduced by carbon. The overall results of the reactions of elements oxidation and reduction consist in the production of CO containing gas and evolving heat. The heat evolved is extracted from the melt by submergence of solid to be heated into the melt, by injection of heated gases into molten slag, by heat exchange between the wall confining the melt and gas, liquid or solid to be heated, or by conversion of steam into H.sub.2 and CO.
    Type: Grant
    Filed: May 2, 1983
    Date of Patent: December 31, 1985
    Inventor: Ernest S. Geskin