Patents Examined by Doborah Yee
  • Electric resistance welded steel pipe
    Patent number: 9726305
    Abstract: An electric resistance welded steel pipe which has sufficient strength and low-temperature toughness and a low yield ratio and which is suitable as a line pipe to be laid in depths of the sea, characterized in that: the composition of the base material contains, in mass %, 0.05 to 0.10% of C, 1.00 to 1.60% of Mn, and 0.005 to less than 0.035% of Nb, and has a Ceq value of 0.23 to 0.38; and the metal microstructure of the base material contains 3 to 13% of martensite in area fraction with the balance being ferrite.
    Type: Grant
    Filed: September 27, 2013
    Date of Patent: August 8, 2017
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Yasuhiro Shinohara, Kensuke Nagai, Masakazu Ozaki