Threaded joint for steel pipes
AssigneeSumitomo Metal Industries, Ltd.
InventorsKunio GOTO, Ryuichi Imai
Life of this patent
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Abstract
A threaded joint for steel pipes for use in an oil well which has improved galling resistance and which is protected from rusting comprises a pin and a box each having a contact surface including a threaded portion and an unthreaded metal contact portion. The contact surface of at least one of the pin and the box has a lower layer of a viscous liquid or semisolid lubricating coating comprising at least wax and a fatty acid alkaline earth metal salt and not containing a harmful heavy metal such as lead and an upper layer of a dry solid coating formed from an aqueous resin coating composition, an organic solvent type coating composition, or an ultraviolet curing coating composition.
Claims6
1-20. (canceled)
An oil well pipe or a connecting member having a contact surface including a threaded portion and an unthreaded metal contact portion formed at the end of the threaded portion, characterized in that a dry solid coating based on an ultraviolet curing resin is on the contact surface.
Dependencies are inferred from the claim text.