STEIGROHRVERBINDER IN EINER OELBOHRUNG MIT EINER SCHICHT ZUM SCHUTZ VOR KORROSION.

摘要

A threaded joint having high crevice-corrosion resistance for high-alloy oil-well tubing containing not less than 7.5% by weight of Cr has those parts, including the sealing surface, of the joint that are directly exposed to a corroding environment covered with a coating (16,26) of non-metallic substance 1 to 100 mu m in thickness. The coating consists of a single layer or multiple layers of oxide, nitride or carbide ceramics.