STUDY ON THE BEHAVIOR AND LOCALIZED CORROSION INHIBITION BASED POLYPHOSPHATES OF PIPELINE STEEL API 5L X60 FOR NATURAL GAS

摘要

Soil corrosion is the leading cause of the deterioration of buried gas pipelines. The factors that influence corrosion in soil are numerous as soil type, moisture content and the position of the water table, soil resistivity, soluble ion content, soil pH, oxidation-reduction (redox) potential and the rates of microbes in soil corrosion. [1] Most pipelines are made up of low carbon steel. Although susceptible to corrosion, low carbon steel is widely used because of its low cost, high strength and the ease of field make up by welding. Different methods are used to protect these pipelines in harsh environments. In Algeria, buried gas pipelines are usually protected externally by wrapping with polyamide or epoxy resin coating couple with a cathodic protection system with minimum specific potential of - 850mv (Cu/CuSO_4 ). One of the most economical methods of protection is the application of corrosion inhibitors. This article aims to study the efficiency of inhibition of the compound Na_2HP_4 as a corrosion inhibitor of API 5L X60 steel in simulated soil solution.