Patents by Inventor Hans-Joachim Retelsdorf

Hans-Joachim Retelsdorf has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5004886
    Abstract: A consumable nickel-tungsten-carbon electrode is used in arc welding deposition of a corrosion resistant layer producing a nickel-alloy matrix containing tungsten carbide inclusions on a surface of a metal workpiece by electric arc deposition under parameters such that there is either practically no solubilization of the tungsten carbide grains in the filling of the nickel tube of the electrode or there is substantially complete solubilization of the tungsten carbide grains and reprecipitation of the tungsten carbide inclusions in the matrix on cooling.
    Type: Grant
    Filed: May 18, 1990
    Date of Patent: April 2, 1991
    Assignee: Durum Verschleissschutz GmbH
    Inventors: Dieter Born, Peter Knauf, Hans-Joachim Retelsdorf
  • Patent number: 4748009
    Abstract: Process for the recovery of vanadium from vanadium-containing source materials under the addition of additives, especially alkali metal compounds, particularly the carbonates, chlorides, sulfates as well as nitrates and/or mixtures of these compounds, whereby the source material is ground and roasted. The roasted material is leached and whereby the withdrawn leach solution is hydrometallurgically treated for the recovery of vanadium compounds. The source materials are first roasted without the addition of alkali additives and subsequently are leached in a first leaching step. To the residues of the first leaching step are added alkali additives and the mixture is roasted in a second roasting step. The roasting products are again leached.
    Type: Grant
    Filed: October 2, 1986
    Date of Patent: May 31, 1988
    Assignee: GfE Gesellschaft fur Elektrometallurgie mbH
    Inventors: Reinhard Hahn, Siegfried Sattelberger, Rudolf Fichte, Hans-Joachim Retelsdorf
  • Patent number: 4643874
    Abstract: Titanium-containing hydrogen storage alloys with a Laves phase composition AB.sub.2 are made in which the A component is titanium and possibly an element from the start of the transition metal groups of the Periodic Table. According to the invention a titanium-free prealloy is first formed and this prealloy is comminuted and smelted again with addition of titanium and possibly zirconium in a second vacuum furnace stage. The latter melt is then deoxidized with cerium mischmetal. Hydrogen storage capacities of about 2% by weight and above that conventionally obtained can be made.
    Type: Grant
    Filed: March 22, 1985
    Date of Patent: February 17, 1987
    Assignee: GfE Gesellschaft fur Elektrometallurgie mbH
    Inventors: Rudolf Fichte, Hans-Joachim Retelsdorf, Peter K. Kunert
  • Patent number: 4623386
    Abstract: A method of making cobalt-boron and/or nickel-boron alloys in a low-shaft electrical furnace wherein the burden or charge has a height of at least 500 mm and at least a portion of its carbon carrier consists of wood chips which are carbonized to wood charcoal during the process so that the wood charcoal which is produced can adsorb volatilized boron compounds and tap them so that they do not escape. The volatilized boron compounds thus tapped are carried to the reduction zone by the wood charcoal so that a high yield is obtained and the product has a low aluminum content.
    Type: Grant
    Filed: December 13, 1985
    Date of Patent: November 18, 1986
    Assignee: GfE Gesellschaft fur Elektrometallurgie mbH
    Inventors: Reinhard Hahn, Hans-Joachim Retelsdorf, Rudolf Fichte, Siegfried Sattelberger
  • Patent number: 4569691
    Abstract: A method of making ferroboron or ferroborosilicon alloys in a low-shaft electrical furnace wherein the burden or charge has at least as a major portion of its carbon carrier, wood chips or particles which are carbonized to wood charcoal during the process and thus the charge has a porosity which permits adsorption action to prevent loss of volatile boron compounds. The charge also contains iron oxide and boron oxide, the electrodes of the furnace effecting a reduction of the boron oxide at a reduction zone just above the floor of the furnace.
    Type: Grant
    Filed: March 12, 1985
    Date of Patent: February 11, 1986
    Assignee: GfE Gesellschaft fur Elektrometallurgie mbH
    Inventors: Rudolf Fichte, Friedrich Breuer, Reinhard Hahn, Hans-Joachim Retelsdorf
  • Patent number: 4451292
    Abstract: Spinodally-decomposing mixed crystals of zirconium and titanium carbides, possibly including carbonitrides and optionally including one or more carbides of metals of Group Vb of the Periodic Table of the Elements, are used in making sintered hardmetals based on tungsten carbide. One or more iron group metals or alloys, preferably cobalt or a nickel alloy, is or are used as a binder. The sintered hardmetals are made by a 2-stage process, mixed crystal material comprising zirconium and titanium carbides being formed in the first stage and being combined with the binder and tungsten carbide in the second stage. Process variations which encourage spinodal decomposition of the mixed crystal material are also disclosed.
    Type: Grant
    Filed: September 17, 1981
    Date of Patent: May 29, 1984
    Inventors: Fred W. Hall, Hans-Joachim Retelsdorf
  • Patent number: 4417922
    Abstract: Mixed crystals of zirconium and hafnium carbides, possibly including the carbonitrides, are used in place of tantalum carbide in sintered hard metals. The new products contain one or more hard metals of Groups IV to VI of the Periodic Table of the Elements other than the mixed crystals, in particular, titanium and tungsten carbides, possibly with carbides of vanadium, niobium, molybdenum or chromium, and one or more iron group metals or alloys, preferably cobalt, is or are used as a binder. The sintered hard metals are made essentially by a 2-stage process, mixed crystal material comprising zirconium and hafnium carbides being formed in the first stage and being combined with the binder in the second stage, the one or more other hard metals of Groups IV to VI being incorporated in one or both stages. Any tendency to microporosity, shown particularly by products having a nitrogen content, is avoided by hot isostatic pressing.
    Type: Grant
    Filed: July 20, 1981
    Date of Patent: November 29, 1983
    Inventors: Fred W. Hall, Hans-Joachim Retelsdorf
  • Patent number: 4263046
    Abstract: A workpiece of alloy steel is produced by sintering under a nonoxidizing atmosphere a mass of malleable-iron powder admixed with a comminuted complex ferroalloy. The latter, obtained from a molten mixture of several simple high-carbon ferroalloys saturated with graphite, is a blend of at least three nonferrous metals and iron in carbide form, including a complex carbide of formula M.sub.7 C.sub.3 containing iron and manganese with the possible addition of chromium and another carbide of formula M'.sub.2 C/M'C containing molybdenum with the possible addition of vanadium and/or niobium. The carbidically bound carbon amounts to at least 4%, by weight, of the ferroalloy composition and may constitute between 10% and 60% of the carbon of the sinterable powder mixture to which elemental carbon may be added as graphite. As the mass of iron and ferroalloy particles compacted under high pressure is sintered at temperatures between about 1150.degree. and 1300.degree. C.
    Type: Grant
    Filed: September 26, 1978
    Date of Patent: April 21, 1981
    Assignee: GfE Gesellschaft fur Elektrometallurgie mit beschrankter Haftung
    Inventors: Rudolf Fichte, Hans-Joachim Retelsdorf, Richard Jervis, Gunter Radel