Corrosion of Underground Gas and Liquid Transmission Pipelines

Corrosion of the pipe wall can occur either internally or externally. Internal corrosion occurs when corrosive liquids or condensates are transported through the pipelines. Depending on the nature of the corrosive liquid and the transport velocity, different forms of corrosion may occur, including uniform corrosion, pitting/crevice corrosion, and erosion-corrosion. 

There are several different modes of external corrosion identified in buried pipelines. The primary mode of corrosion is a macrocell form of localized corrosion because of the heterogeneous nature of soils, local damage of the external coatings 

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