Patents Assigned to Nippin Steel Corporation
  • Patent number: 6428633
    Abstract: In order to conduct welding so that the welded steel shows a decreased residual stress after welding without a post treatment such as a PWHT, the steel for welded structures and the welding wire of the present invention starts a transformation from austenite into martensite at a temperature (Ms temperature) from at least 200° C. to up to 350° C., and has a yield strength from at least 60 kg/mm2 to up to 120 kg/mm2 at the transformation starting temperature. The multipass welding process of the present invention comprises forming a weld metal having a Ms temperature of 150° C. to 300° C., and TIG remelt-run welding the surface of the final layer.
    Type: Grant
    Filed: October 19, 1998
    Date of Patent: August 6, 2002
    Assignee: Nippin Steel Corporation
    Inventors: Tadashi Kasuya, Shigeru Ohkita, Masao Fuji, Naoki Saitou, Junichi Kobayashi, Toshihiko Chiba