Invention Grant
- 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
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Application No.: US10361556Application Date: 2003-02-11
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Publication No.: US06827996B2Publication Date: 2004-12-07
- Inventor: Kunio Goto
- Applicant: Kunio Goto
- Priority: JP2001-112884 20010411; JP2001-134576 20010501
- Main IPC: B32B108
- IPC: B32B108

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.
Public/Granted literature
- US20030159764A1 Threaded joint for steel pipes and process for the surface treatment thereof Public/Granted day:2003-08-28
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