THREADED JOINT FOR STEEL PIPES

摘要

FIELD: threaded joints for steel pipes. ^ SUBSTANCE: proposed threaded joint has dowel pin and bush with contact surface each; contact surface includes section with thread and section without thread which is used for contact with metal. Contact surface of at least only dowel pin or only bush is coated with primer layer over which covering lubricating layer is applied. Primer layer is just coat made from porous metal at porosity of 5-80% and thickness of 1-30 mcm. Lubricating coat is made in form of solid coat practically free from powders of hard metals. Maximum total thickness of primer layer and lubricating layer is 100 mcm. Proposed threaded joint for steel pipes ensures hermetic " metal-to-metal" joint and withstands repeated screwing and unscrewing without application of liquid lubricant. ^ EFFECT: enhanced reliability. ^ 6 cl, 4 dwg