Threaded joint for steel pipes and process for the surface treatment thereof

摘要

A threaded joint for steel pipes comprising a pin and a box each having a contact surface including a threaded portion and an unthreaded metal contact portion, characterized in that the contact surface of at least one of the pin and the box has a solid lubricant coating formed thereon which comprises a lubricating powder selected from molybdenum disulfide and/or tungsten disulfide and a resin, the coatig having a hardness of 70-140 on the Rockwell M scale.