Patents Assigned to Nippn Steel Corporation
  • Patent number: RE41033
    Abstract: This invention is directed to improve a wear resistance and a damage resistance required for a rail of a sharply curved zone of a heavy load railway, comprising more than 0.85 to 1.20% of C, 0.10 to 1.00% of Si, 0.40 to 1.50% of Mn and if necessary, at least one member selected from the group consisting of Cr, Mo, V, Nb, Co and B, and retaining high temperature of hot rolling or a steel rail heated to a high temperature for the purpose of heat-treatment, the present invention provides a pearlitic steel rail having a good wear resistance and a good damage resistance, and a method of producing the same, wherein a head portion of the steel rail is acceleratedly cooled at a rate of 1° to 10° C./sec from an austenite zone temperature to a cooling stop temperature of 700° to 500° C. so that the hardness of the head portion is at least Hv 320 within the range of a 20 mm depth.
    Type: Grant
    Filed: November 13, 1995
    Date of Patent: December 8, 2009
    Assignee: Nippn Steel Corporation
    Inventors: Masaharu Ueda, Hideaki Kageyama, Kouichi Uchino, Koji Babazono, Ken Kutaragi