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AssigneesSumitomo Metal Industries, Ltd., Vallourec Mannesmann Oil & Gas France
InventorsMasanari Kimoto, Kunio Goto, Masaru Takahashi, Kunihiro Fukui, Shigeo Nagasaku, Ryuichi Imai, Shigeo Onishi, Hiroaki Ikegami
Estimating the term…
A threaded joint for steel tubes has a contact surface (30) including a threaded portion and a non-threaded metal-to-metal contact portion. The contact surface of at least one of a pin and a box of the joint is coated with a first plating layer (34) made of a Cu—Zn alloy or a Cu—Zn-M1 alloy (wherein M1 is at least one element selected from Sn, Bi, and In). An undercoat (32) of one or both of a Ni plating layer (32a) and a Cu plating layer (32b) and an overcoat of a Sn-M2 alloy plating layer (36) (wherein M2 is one or more elements selected from Bi, In, Ni, Zn, and Cu) may be formed below and above the first layer, respectively. A solid lubricating coating (38a) and a viscous liquid or semisolid lubricating coating (38b) may also be formed atop the plating layer as a lubricating coating (38).
A threaded joint for steel tubes constituted by a pin and a box each having a contact surface including a threaded portion and an unthreaded metal-to-metal contact portion, characterized in that the contact surface of at least one of the pin and the box has a first plating layer made of a Cu—Zn-M1 alloy (wherein M1 is one or more elements selected from Sn, Bi, and In) having a composition of Cu:
Dependencies are inferred from the claim text.