Tubular threaded joint having improved low temperature performance
AssigneesNippon Steel & Sumitomo Metal Corporation, Vallourec Mannesmann Oil & Gas France
InventorsKunio Goto, Masayoshi Sasaki
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Abstract
In order to provide a tubular threaded joint constituted by a pin and a box each having threads and an unthreaded metal contact portion with excellent galling resistance and gas tightness even in extremely cold environments at −60° C. to −20° C. and rust preventing properties without using a compound grease, a thermoplastic solid lubricating coating containing low friction copolymer particles made from an acrylic-silicone copolymer and preferably further containing a solid lubricant (e.g., graphite) in a thermoplastic polymer matrix (e.g., selected from polyolefin resins and ethylene-vinyl acetate copolymer resins) is formed on the surface of the threads and unthreaded metal contact portion of a pin and/or a box.
Claims18
A tubular threaded joint comprising a pin and a box each having contact surface including threads and an unthreaded metal contact portion, characterized in that the contact surface of at least one of the pin and the box has a thermoplastic solid lubricating coating formed as an uppermost surface treatment coating layer, said thermoplastic solid lubricating coating containing particles of a copolymer of a resin selected from a silicone resin and a fluorocarbon resin with a different thermoplastic resin in a thermoplastic polymer matrix.
A composition for forming a thermoplastic solid lubricating coating on a tubular threaded joint characterized by comprising (1) a thermoplastic polymer matrix material, and (2) particles of a copolymer of a resin selected from a silicone resin and a fluorocarbon resin with a different thermoplastic resin.
Dependencies are inferred from the claim text.