Patents by Inventor Friedhelm Retzlaff

Friedhelm Retzlaff 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: 4827099
    Abstract: Method and apparatus for the continuous industrial production of tubular bodies in which coated or uncoated steel strip is formed to a slit tube and the opposite strip edges are longitudinally seam welded at high speed by a laser beam of high energy density under protective gas with or without supply of additive material, and after a preparation adapted to the narrow melt zone and bringing together of the strip edges a fusion welding with subsequent controlled cooling and upsetting is carried out which results in a seam geometry suitable for any further processing.
    Type: Grant
    Filed: September 18, 1987
    Date of Patent: May 2, 1989
    Assignee: Hoesch Aktiengesellschaft
    Inventors: Rolf Krebs, Otto Welsing, Friedhelm Retzlaff, Friedhelm Gunter, Hans-Jurgen Wahl, Manfred Gerber, Heinz Gross
  • Patent number: 4732623
    Abstract: Improved steel profiles having superior material characteristics are obtained by rolling a precipitation-hardenable fine grain steel, cooling it from a final rolling temperature above the A.sub.1 -temperature down to a temperature of about 400.degree. C. in an atmosphere in which it is allowed to overage, whereupon the steel plate or strip is then cooled down to room temperature and cold-processed to form an open profile which can thereupon be converted into a tube by welding together its longitudinally extending edges and which is then subjected to solution-annealing in order-to dissolve coarse precipitants and subsequently further cooled to form finely dispersed precipitants in the profile.
    Type: Grant
    Filed: January 30, 1984
    Date of Patent: March 22, 1988
    Assignee: Hoesch Werke Aktiengesellschaft
    Inventors: Heinz Gross, Friedrich Reith, Friedhelm Retzlaff, Karl H. Schlusnus
  • Patent number: 4656332
    Abstract: A laser welding process is used according to the invention for the manufacture of a straight seam weld for tubular construction parts of ferritic, Ti-stabilized CR steel x5CrTi12 for exhaust systems in automobiles. This has the advantage that after welding the construction parts can be expanded or compressed by more than 40% of their original dimensions.
    Type: Grant
    Filed: December 2, 1985
    Date of Patent: April 7, 1987
    Assignee: Hoesch Aktiengesellschaft
    Inventors: Heinz Gross, Manfred Gerber, Rolf Krebs, Friedhelm Retzlaff
  • Patent number: 4414042
    Abstract: Improved steel profiles having superior material characteristics are obtained by rolling a precipitation-hardenable fine-grain steel, cooling it from a final rolling temperature above the A.sub.1 -temperature down to a temperature of about 400.degree. C. in an atmosphere in which it is allowed to overage, whereupon the steel plate or strip is then cooled down to room temperature and cold-processed to form an open profile [which can thereupon be converted into a tube by welding together its longitudinally extending edges and] which is then subjected to solution-annealing in order to dissolve coarse precipitants and subsequently further cooled to form finely dispersed precipitants in the profile.
    Type: Grant
    Filed: December 26, 1979
    Date of Patent: November 8, 1983
    Assignee: Hoesch Werke Aktiengesellschaft
    Inventors: Heinz Gross, Friedrich Reith, Friedhelm Retzlaff, Karl H. Schlusnus