Patents by Inventor John C. Tobin

John C. Tobin 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).

  • Process for stabilizing dimensions of duplex stainless steels for service at elevated temperatures
    Patent number: 4263063
    Abstract: Duplex stainless steel materials containing austenite plus delta ferrite, are dimensionally stabilized by heating the material to a reaction temperature between about 1050.degree.-1450.degree. F. (566.degree.-788.degree. C.), holding it at this temperature during transformation of delta ferrite to austenite plus sigma phase, and subsequently heating to a reversion temperature between about 1625.degree.-1750.degree. F. (885.degree.-954.degree. C.), whereby the sigma phase transforms back to ferrite, but the austenite remains dispersed in the ferrite phase. Final controlled cooling permits transformation of ferrite to austenite plus sigma and, later, precipitation of carbides.
    Type: Grant
    Filed: July 5, 1979
    Date of Patent: April 21, 1981
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Frederick C. Hull, John C. Tobin