Patents Assigned to Durferrit GmbH
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Patent number: 8747573Abstract: The invention relates to a method for producing corrosion-resistant surfaces of nitrated or nitrocarburated steel components, the surfaces having roughness heights (Rz) of Rz?1.5 ?m. The method comprises the following steps: oxidation of the surfaces of the nitrated or nitrocarburated components in a first oxidation step; carrying out at least a second oxidation of the component surfaces in an immediately subsequent oxidation step; polishing the component surface in a final method step, directly after the final oxidation.Type: GrantFiled: October 29, 2008Date of Patent: June 10, 2014Assignee: Durferrit GmbHInventor: Ulrich Baudis
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Patent number: 8092214Abstract: The invention relates to a method for the continuous melting of inorganic salts and a furnace installation for realizing the method. Solid salts are fed into a furnace with the aid of a feeding unit. The salts contained in the furnace are heated. A flow of the salts is generating inside the furnace with the aid of a circulating unit. The flow generates a two-phase region containing solid and melted salt and a separate second region containing substantially solely a melt that is heated to the desired temperature. The melt is discharged from the separate second region simultaneous with the feeding of the solid salts into the furnace with the aid of a removal unit.Type: GrantFiled: March 24, 2008Date of Patent: January 10, 2012Assignee: Durferrit GmbHInventors: Michel Heinrich, Hans-Helmut Trapp
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Patent number: 8083866Abstract: A method for hardening the surfaces of work pieces made from stainless steel includes submerging the work pieces into a molten salt bath having the composition: potassium acetate 60-100 weight %; sodium acetate 0-100 weight %; metal salt 0-2 weight %, and are subjecting the work pieces to the molten salt bath for a period of 24 to 240 hours, during which the temperature of the molten salt bath is maintained less than 400° C.Type: GrantFiled: October 31, 2008Date of Patent: December 27, 2011Assignee: Durferrit GmbHInventors: Ulrich Baudis, Michael Merz
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Publication number: 20110160450Abstract: The invention relates to an explosive comprising 2,6,10-trinitro-s-heptazine and/or derivatives thereof as an active chemical compound.Type: ApplicationFiled: July 24, 2009Publication date: June 30, 2011Applicant: DURFERRIT GMBHInventor: Ulrich Baudis
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Patent number: 7909943Abstract: A process for hardening a work piece of stainless steel through diffusion of the elements carbon and/or nitrogen into the work piece surfaces. The work piece is submerged into a molten salt bath and subjected to the molten salt bath for a period ranging from 15 minutes to 240 hours at temperatures below 450° C. In addition to potassium chloride and lithium chloride, the molten salt bath contains an activator substance consisting of barium chloride, strontium chloride, magnesium chloride and/or calcium chloride, and a free or complex cyanide as carbon-donating substance.Type: GrantFiled: June 11, 2007Date of Patent: March 22, 2011Assignee: Durferrit GmbHInventors: Ulrich Baudis, Michael Niedermeyer
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Publication number: 20100243109Abstract: The invention relates to a method for producing corrosion-resistant surfaces of nitrated or nitrocarburated steel components, the surfaces having roughness heights (Rz) of Rz?1.5 ?m. The method comprises the following steps: oxidation of the surfaces of the nitrated or nitrocarburated components in a first oxidation step; carrying out at least a second oxidation of the component surfaces in an immediately subsequent oxidation step; polishing the component surface in a final method step, directly after the final oxidation.Type: ApplicationFiled: October 29, 2008Publication date: September 30, 2010Applicant: Durferrit GmbHInventor: Ulrich Baudis
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Publication number: 20100108198Abstract: A method for hardening the surfaces of work pieces made from stainless steel includes submerging the work pieces into a molten salt bath having the composition: potassium acetate 60-100 weight %; sodium acetate 0-100 weight %; metal salt 0-2 weight %, and are subjecting the work pieces to the molten salt bath for a period of 24 to 240 hours, during which the temperature of the molten salt bath is maintained less than 400° C.Type: ApplicationFiled: October 31, 2008Publication date: May 6, 2010Applicant: Durferrit GmbHInventors: Ulrich Baudis, Michael Merz
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Publication number: 20080233527Abstract: The invention relates to a method for the continuous melting of inorganic salts and a furnace installation for realizing the method. Solid salts are fed into a furnace with the aid of a feeding unit. The salts contained in the furnace are heated. A flow of the salts is generating inside the furnace with the aid of a circulating unit. The flow generates a two-phase region containing solid and melted salt and a separate second region containing substantially solely a melt that is heated to the desired temperature. The melt is discharged from the separate second region simultaneous with the feeding of the solid salts into the furnace with the aid of a removal unit.Type: ApplicationFiled: March 24, 2008Publication date: September 25, 2008Applicant: Durferrit GmbHInventors: Michel Heinrich, Hans-Helmut Trapp
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Publication number: 20080099108Abstract: A process for hardening a work piece of stainless steel through diffusion of the elements carbon and/or nitrogen into the work piece surfaces. The work piece is submerged into a molten salt bath and subjected to the molten salt bath for a period ranging from 15 minutes to 240 hours at temperatures below 450° C. In addition to potassium chloride and lithium chloride, the molten salt bath contains an activator substance consisting of barium chloride, strontium chloride, magnesium chloride and/or calcium chloride, and a free or complex cyanide as carbon-donating substance.Type: ApplicationFiled: June 11, 2007Publication date: May 1, 2008Applicant: Durferrit GmbHInventors: Ulrich Baudis, Michael Niedermeyer
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Patent number: 6964712Abstract: Hardening protection compositions based on substances which form boron glass for partial carburization of metallic components, which contain magnesium-silicon compounds as an additive. These hardening protection compositions can be used very advantageously in processes for the partial carburization of metallic components and in particular are outstandingly suitable for vacuum carburization.Type: GrantFiled: August 7, 2001Date of Patent: November 15, 2005Assignee: Durferrit GmbHInventors: Stefan Wigger, Ulrich Baudis
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Patent number: 6503344Abstract: A boronizing agent in the form of a paste for the production of boride layers on metallic workpieces. The boronizing agent contains boron-releasing substances, activating substances and the remainder of inert, refractory extenders together with water and optionally auxiliaries required for paste formulation. It contains as additives: (a) calcium carbonate and/or lithium carbonate; (b) at least one compound from the group of alkali metal and alkaline earth metal nitrites; (c) at least one compound from the group of water soluble alkali metal and alkaline earth metal borates.Type: GrantFiled: September 24, 2001Date of Patent: January 7, 2003Assignee: Houghton Durferrit GmbHInventors: Ulrich Baudis, Stefan Wigger
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Patent number: 6245162Abstract: A boriding agent for generating boride layers on metallic workpieces, containing boron-releasing substances, activating substances and, in the remainder, refractory, inert extender. The activating substance is a combination of 1 to 5 wt. % potassium tetrafluoroborate and 5 to 40 wt. % calcium fluoride, relative to the total quantity of the boriding agent. With this boriding agent it is possible for single-phase, Fe2B-containing boride layers to be generated on workpieces made of ferrous materials. The agent results in lower emissions of fluorine and fluoride.Type: GrantFiled: July 8, 1999Date of Patent: June 12, 2001Assignee: Houghton Durferrit GmbHInventors: Ulrich Baudis, Stefan Wigger
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Patent number: 6159355Abstract: In order to shorten the waiting times until the equilibrium between cyanate and cyanide is established and to limit the use of substances and products containing cyanide for nitrocarburizing in salt melts, melts containing only cyanate and optionally carbonate are electrolyzed at a current density of 4 to 100 A/dm.sup.2 of electrode area to form an advantageous cyanide content of 1 to 5 wt. %.Type: GrantFiled: July 16, 1999Date of Patent: December 12, 2000Assignee: Houghton Durferrit GmbHInventors: Ulrich Baudis, Mandy Doose, Karl-Otto Prietzel
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Patent number: 6085827Abstract: A casting apparatus has within a heating chamber (6) and a mold (5) which can be removed from the heating chamber into a molten quenching metal (10) disposed underneath it. As a thermal barrier between the heating chamber (6) and the quenching metal (10), a thermal insulating layer (13) floating on the molten quenching metal (10) is provided, through which the mold (5) plunges into the molten quenching metal (10).Type: GrantFiled: November 16, 1993Date of Patent: July 11, 2000Assignee: Leybold Durferrit GmbHInventor: Franz Hugo
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Patent number: 5846501Abstract: In order to recover in an environmentally sound and economic manner used hardening shop salts which contain nitrate-nitrite, the salts, comminuted to particle sizes of from 1 to 50 mm, are dissolved in a mixture of nitric acid and hydrogen peroxide without nitrogen oxides arising, and, by evaporation and cooling, potassium nitrate, sodium chloride, and sodium nitrate are obtained sequentially by fractional crystallization.Type: GrantFiled: April 11, 1997Date of Patent: December 8, 1998Assignee: Durferrit GmbH ThermotechnikInventors: Matthias Kremer, Georg Wahl, Eberhard Gock, Stefan Wigger, Jorg Kahler
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Patent number: 5769906Abstract: The process for environmentally acceptable and economical recovery of chloride salts from hardening-shop used salts utilizing the steps of leaching of the used salt, detoxification of the cyanide and selective crystallization of the individual chloride salts. The process is characterized in that all the chloride salts that are present in the hardening-shop used salt are recovered in pure form.Type: GrantFiled: September 27, 1996Date of Patent: June 23, 1998Assignee: Durferrit GmbH ThermotechnikInventors: Mattias Kremer, Georg Wahl, Eberhard Gock, Stefan Wigger, Jorg Kahler
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Patent number: 5735971Abstract: Flawless nitrating layers are obtained during the nitro-carburizing of components made from steels which form passive layers in salt baths if these components are first pre-treated in an oxidizing salt melt at 300.degree. to 500.degree. C. prior to the nitro-carburizing process.Type: GrantFiled: November 28, 1995Date of Patent: April 7, 1998Assignee: Durferrit GmbH ThermotechnikInventors: Georg Wahl, Rainer Willing-Lepenies
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Patent number: 5544194Abstract: Apparatus for the cleaning, especially degreasing, of electrically conductive material (9), for example metal and/or ceramic turning chips and/or grinding sludges, under vacuum conditions, essentially consisting of a container (4) and at least two electrodes (4,5) which are connected to a power supply unit (8), the material (9) to be cleaned being heatable by the two electrodes (4,5) by direct passage of current.Type: GrantFiled: September 23, 1994Date of Patent: August 6, 1996Assignee: Leybold Durferrit GmbHInventors: Franz Hugo, Erwin Wanetzky
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Patent number: 5527018Abstract: In a filter unit (25) and apparatus for desludging salt baths (1), which is flooded at least partially by the salt bath and is in working association with the upper end of a riser tube (23), the bath fluid to be desludged being driven, by means of a compressed air stream, for example, through the riser tube (23) toward the filter unit (9, 25), the filter cloth packet is made of woven wire of a nonferrous metal, preferably an alloy based on aluminum, nickel or titanium, and is surrounded by a filter frame (14), the frame (14) being shaped into a shallow, pyramidal frustum-shaped funnel (18) pointing toward the bottom of the vat, its apical bottom end being provided with a closable opening (19).Type: GrantFiled: November 21, 1994Date of Patent: June 18, 1996Assignee: Durferrit GmbH ThermotechnikInventors: George Wahl, Matthias Kremer, Tokuo Sato
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Patent number: 5505008Abstract: Material containing organic substances including rubber, plastic, and lacquer is heated in a vacuum process chamber at subatmospheric pressure in a nonreactive atmosphere to a temperature of at least 200.degree. C., the gases and vapors thus formed are condensed in a condensate separator, and the condensate is captured and made available for reuse or disposal. The embrittled residues formed from these substances are crushed and the crushed residues are collected and made available for recycling or disposal. If metals are contained in the material, the residues are loosened, collected, and crushed. The process and the apparatus are suitable for recycling insulted wire, metal bonded to rubber, plastic containers decorated with pigments, motor vehicle steering wheels, workpiece hangers and tools coated with lacquer, poorly lacquered metal parts, tires and rubber pads of track-laying vehicles, and seals.Type: GrantFiled: June 23, 1994Date of Patent: April 9, 1996Assignee: Leybold Durferrit GmbHInventors: Franz Hugo, Helmut Teuschel, Erwin Wanetzky