The Problem of Corrosion in Pipelines

Pipelines condition is space-dependent, defined by the soil properties surrounding the pipeline, the way pipes are installed (e.g., underground, aboveground), and the efficiency of protection measures (e.g., coatings, cathodic protection). Pipelines are subjected to different threats, which can be classified as manufacturing or mechanical failures, operational failures, third-party actions, natural forces, or corrosion attacks. This chapter focuses on the corrosion thinning at the inner or the outer pipelines walls. Corrosion defects may follow different degradation mechanisms depending on the properties of the soil surrounding the pipe, the fluid being transported, and the mechanical condition of the pipe. This chapter describes the pipelines main corrosion mechanisms and their common preventive measures. Corrosion mechanisms include uniform (general) corrosion, pitting, erosion-corrosion, stray current corrosion, Microbiologically-Influenced Corrosion (MIC), and stress corrosion cracking. This chapter also presents the main contributions from the soil properties, operation and fluid factors, and the material properties of the corrosion degradation. The main objective is to identify the principal factors favoring corrosion degradation of underground pipelines.