External Damage by Corrosion on Steel Gas Pipeline

A. Benmoussat1, H. Hadjiat1 and M. Hadjel2

1Faculty of Engineering Sciences, Laboratory of Material Sciences, University of Tlemcen,

BP 230 chetouan 13000, Tlemcen, Algeria

2Faculty of Sciences, Industrial Chemistry Department, University of Sciences and Technology,

BP 1505 Oran, 31000, Algeria

Abstract

Under degraded coatings and inadequate cathodic protection (CP) steel gas pipelines exposed to environmentally assisted multiple corrosion. In electrochemical process corrosion, dissolution of the iron is an anodic reaction. The nature of the cathodic process depends on the availability of oxygen and implies aerobics or anaerobics conditions. The most severe corrosion process is that of microbiologically influenced corrosion. Damage can be a localized corrosion or SCC corrosion (Stress corrosion cracking). Microstructural damage is intergranular type at low stress intensity and implies the interaction of the material with the corrosive environment characterized by the apparition of corrosion microcracks.