Patents by Inventor Alf Tryggmo

Alf Tryggmo 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: 6342087
    Abstract: The invention concerns a process for producing low oxygen, essentially carbon free stainless steel powder, which comprises the steps of preparing molten steel which in addition to iron contains carbon and at least 10% of chromium, adjusting the carbon content of the melt to a value which is decided by the expected oxygen content after water atomising; water-atomising the melt and annealing the as-atomised powder at a temperature of at least 1120° C. in a reducing atmosphere containing controlled amounts of water. The invention also concerns a water-atomised powder including 10% by weight of chromium and having a carbon content between 0.2 and 0.7, preferably between 0.4 and 0.6% by weight and an oxygen/carbon ratio of about 1 to 3 and at most 0.5% of impurities, as well as the annealed powder obtained according to the process.
    Type: Grant
    Filed: December 17, 1999
    Date of Patent: January 29, 2002
    Assignee: Höganäs AB
    Inventors: Johan Arvidsson, Alf Tryggmo