| abstract |
A threaded joint for an oil well pipe, characterized as having a screw part and/or a metal-metal contacting part with no screws which have, formed thereon, 1) a lubricating coating of an inorganic polymer having a skeleton of M (metal atom)-O (oxygen) and containing a solid lubricating agent dispersed and incorporated therein, 2) a phosphate coating and the above lubricating coating of an inorganic polymer, 3) a Cu plating layer, and the above lubricating coating of an inorganic polymer or a lubricating coating of a resin containing a solid lubricating agent dispersed and incorporated therein, or 4) the above lubricating coating of an inorganic polymer or the above lubricating coating of a resin, and a rust-inhibiting coating containing an alkali metal or alkaline earth metal salt of a carboxylic acid. The threaded joint for an oil well pipe can prevent the occurrence of galling in repeated make-up and break-out operations and at the same time secure high oil-tightness, with no use of a liquid lubricating agent such as a compounded grease. |