Invention Grant
US06827996B2 Threaded joint for steel pipes and process for the surface treatment thereof 有权
钢管螺纹接头及其表面处理工艺

  • Patent Title: Threaded joint for steel pipes and process for the surface treatment thereof
  • Patent Title (中): 钢管螺纹接头及其表面处理工艺
  • Application No.: US10361556
    Application Date: 2003-02-11
  • Publication No.: US06827996B2
    Publication Date: 2004-12-07
  • Inventor: Kunio Goto
  • Applicant: Kunio Goto
  • Priority: JP2001-112884 20010411; JP2001-134576 20010501
  • Main IPC: B32B108
  • IPC: B32B108
Threaded joint for steel pipes and process for the surface treatment thereof
Abstract:
This invention relates to a threaded joint for steel pipes which comprises a pin and a box each having a contact surface including a threaded portion and an unthreaded metal contact portion and which can be prevented from galling during repeated fastening and loosening without application of a compound grease. A solid lubricant coating which comprises a lubricating powder such as molybdenum disulfide and a resin binder is formed on the contact surface of at least one of the pin and the box. The solid lubricant coating has a hardness of 70-140 on the Rockwell M scale and an adhesive strength of at least 500 N/m as determined by the SAICAS (Surface And Interfacial Cutting Analysis System) method, and it exhibits excellent galling resistance even in the environment of high-temperature oil wells. Inclusion of ultraviolet screening fine particles such as titanium oxide fine particles in the solid lubricant coating increases the rust preventing properties of the threaded joint.
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