THREADED JOINT FOR STEEL PIPE EXCELLENT IN SEIZURE RESISTANCE AND RUST PREVENTABILITY

摘要

PROBLEM TO BE SOLVED: To provide a threaded joint for a steel pipe which is excellent in seizure resistance, rust preventability and airtightness, and can be fastened and loosened repeatedly even in a high temperature circumstance without using a compound grease containing a heavy metal powder.;SOLUTION: On the threaded part or non-threaded metal contacting part of at least either one of a pin or a box, of which the threaded joint for a steel pipe is composed, a porous zinc or zinc alloy layer is formed by a mechanical plating method. Further, on the porous layer, a liquid lubrication film containing no solid lubrication film or heavy metal powder (e.g. a film comprising a highly basic organic metal salt such as highly basic sulfonate as a main component) is formed.;COPYRIGHT: (C)2002,JPO