Invention Grant
US06746057B2 Threaded joint for steel pipes having improved galling resistance and rust-preventing properties 有权
钢管螺纹接头具有改善的耐磨损性和防锈性能

  • Patent Title: Threaded joint for steel pipes having improved galling resistance and rust-preventing properties
  • Patent Title (中): 钢管螺纹接头具有改善的耐磨损性和防锈性能
  • Application No.: US10253421
    Application Date: 2002-09-25
  • Publication No.: US06746057B2
    Publication Date: 2004-06-08
  • Inventor: Kunio GotoToshiro Anraku
  • Applicant: Kunio GotoToshiro Anraku
  • Priority: JP2001-017257 20010125
  • Main IPC: F16L1504
  • IPC: F16L1504
Threaded joint for steel pipes having improved galling resistance and rust-preventing properties
Abstract:
In a threaded joint for steel pipes comprising a pin and a box capable of mating with each other, the pin having an externally threaded portion and an unthreaded metal contact portion as a mating surface, and the box having an internally threaded portion and an unthreaded metal contact portion as a mating surface, the mating surface of at least one of the pin and the box is coated with a lower porous zinc or zinc alloy layer by blast plating and with an upper coating which is either a solid lubricating coating (comprising a lubricating powder in an organic or in organic binder) or a liquid, heavy metal powder-free coating (e.g., a liquid coating based on a highly basic organic acid metal salt such as a highly basic metal sulfonate). The threaded joint exhibits improved galling resistance, rust-preventing properties, and gas tightness even after exposure to a high temperature and makes it possible to perform repeated fastening (make-up) and loosening (break-out) in a high-temperature oil well without application of a compound grease containing a heavy metal powder.
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