Role Of Localized Attacks In NN-SCC On Gas Pipelines

The paper deals with the effects of localized attacks on Near Neutral Stress Corrosion Cracking (NN-SCC) of buried pipelines. NN-SCC takes place in neutral ground waters with low partial pressure of CO2, at free corrosion potential, under disbonded continuous coatings where cathodic protection cannot penetrate. Cracking occurs on areas with severe generalized corrosion, from localized attacks. An electrochemical pre-corrosion technique has been made in order to produce localized attack significant for NN-SCC initiation, producing cracking morphology similar to that found on failed pipelines.