LUBRICATING COATING COMPOSITION SUITABLE FOR LUBRICATION OF A THREADED JOINT

摘要

A lubricating coating composition in which at least one basic lubricant selected from a basic sulfonate, a basic salicylate, and a basic phenate is dissolved in a volatile solvent is applied to the frictional surface of a box and a pin constituting a threaded joint for oil well pipes. The composition may further contain one or more of a thermoplastic resin powder, another lubricant, and an extreme pressure agent . The surface roughness of the frictional surfaces preferably has an Rmax in the range of - -40 micrometers.