THREADED JOINT FOR STEEL PIPES

摘要

A threaded joint for steel pipes having excellent galling resistance, rust preventing properties, and airtightness without using a compound grease comprises a pin and a box each having a threaded portion and an unthreaded metal-to-metal contact portion serving as contact surfaces. The contact surfaces of at least one of the pin and the box are coated with a multi-layered structure comprising, from the bottom, a first layer formed from a first metal or alloy, a second layer formed from a second metal or alloy which is softer than the first metal or alloy, and an uppermost layer of a solid lubricating coating comprising a lubricating powder in an organic or inorganic binder.