Patents by Inventor William A. Pratt

William A. Pratt 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: 6623569
    Abstract: A duplex stainless steel includes less than, in weight percent, 3 percent nickel and 1.5 percent molybdenum. In one embodiment, the duplex stainless steel includes, in weight percent, up to 0.06 percent carbon; 15 to 25 percent chromium; 1 to less than 2.5 percent nickel; greater than 2 percent up to 3.75 percent manganese; greater than 0.12 up to 0.35 percent nitrogen; up to 2 percent silicon; up to 1.5 percent molybdenum; up to 0.5 percent copper; up to 0.2 percent cobalt; up to 0.05 percent phosphorous; up to 0.005 percent sulfur; 0.001 to 0.0035 percent boron; iron and incidental impurities. The duplex stainless steel provided may be provided in the form of an article of manufacture, such as strip, bar, plate, sheet, casting, tubing or piping. A method for making the duplex stainless steel of the invention also is disclosed.
    Type: Grant
    Filed: September 10, 2002
    Date of Patent: September 23, 2003
    Assignee: ATI Properties, Inc.
    Inventors: David S. Bergstrom, John J. Dunn, John F. Grubb, William A. Pratt
  • Publication number: 20030084971
    Abstract: A duplex stainless steel includes less than, in weight percent, 3 percent nickel and 1.5 percent molybdenum. In one embodiment, the duplex stainless steel includes, in weight percent, up to 0.06 percent carbon; 15 to 25 percent chromium; 1 to less than 2.5 percent nickel; greater than 2 percent up to 3.75 percent manganese; greater than 0.12 up to 0.35 percent nitrogen; up to 2 percent silicon; up to 1.5 percent molybdenum; up to 0.5 percent copper; up to 0.2 percent cobalt; up to 0.05 percent phosphorous; up to 0.005 percent sulfur; 0.001 to 0.0035 percent boron; iron and incidental impurities. The duplex stainless steel provided may be provided in the form of an article of manufacture, such as strip, bar, plate, sheet, casting, tubing or piping. A method for making the duplex stainless steel of the invention also is disclosed.
    Type: Application
    Filed: September 10, 2002
    Publication date: May 8, 2003
    Inventors: David S. Bergstrom, John J. Dunn, John F. Grubb, William A. Pratt
  • Patent number: 6551420
    Abstract: A duplex stainless steel including, in weight percent, up to 0.06 percent carbon, 15 up to less than 25 percent chromium, greater than 3 up to 6 percent nickel, up to 3.75 percent manganese, 0.14 up to 0.35 percent nitrogen, up to 2 percent silicon, greater than 1.4 up to less than 2.5 percent molybdenum, up to less than 0.5 percent copper, up to less than 0.2 percent cobalt, up to 0.05 percent phosphorous, up to 0.005 percent sulfur, and 0.001 up to 0.0035 percent boron, with the remainder being iron and incidental impurities is disclosed. The duplex stainless steel may be included in an article of manufacture, such as a strip, bar, plate, sheet, casting, tubing or piping. A method for making such a duplex stainless steel is also disclosed.
    Type: Grant
    Filed: October 16, 2001
    Date of Patent: April 22, 2003
    Assignee: ATI Properties, Inc.
    Inventors: David S. Bergstrom, John J. Dunn, John F. Grubb, William A. Pratt