Patents by Inventor Per I. Hellman

Per I. Hellman 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).

  • Tool steel
    Patent number: 4780139
    Abstract: A vanadium-containing power tool steel is disclosed. The steel is compacted to full density at high temperature and presence and contains M.sub.6 C or M.sub.7 C.sub.3 carbides. The carbides have an effective maximal size of 4 to 15 microns.
    Type: Grant
    Filed: January 16, 1986
    Date of Patent: October 25, 1988
    Assignee: Kloster Speedsteel AB
    Inventors: Per I. Hellman, Henry L. Wisell