Inhibition of stress-corrosion cracking of steel pipeline

Abstract

A method for inhibiting stress-corrosion cracking of a steel pipeline transmitting gas under elevated pressure provided with an external protective coating and means for cathodic protection, and steep pipe and pipelines so protected are described. The method consists of introducing a composition containing at least one of the inhibitors, calcium monobasic phosphate, sodium monobasic phosphate, sodium tripolyphosphate and potassium silicate, into a buried pipeline environment. The inhibiting composition may be simply introduced to the environment adjacent the pipeline or it may be incorporated in a coating on the pipeline, either in the primer or in a top coating thereover or in an intermediate coating between a conventional primer and topcoating, or in a tape applied to the pipeline.

Dependencies are inferred from the claim text.