3377 Guidelines for external corrosion and degradation management of stainless steels in the offshore oil and gas environment

Overview:

This publication provides general principles and engineering guidance for the management of external corrosion and degradation of stainless steels in the offshore oil and gas environment. Some of the principles may also have relevance to onshore facilities. Stainless steels suffer a range of corrosion and related degradation mechanisms in the marine environment, including pitting corrosion, crevice corrosion and chloride stress corrosion cracking. The dominant factors that cause corrosion and degradation are temperature, chloride ions and dissolved oxygen in wet conditions on the surface of the steel. External degradation of stainless steels by corrosion and stress corrosion cracking processes can be controlled by selecting resistant grades and/or the application of protective coatings. Any selection process requires an assessment of the corrosivity of the external environment and the corrosion and related degradation mechanisms that may occur. Decisions on material selection and corrosion protection options normally are taken within a corporate risk matrix by including factors that affect the potential for failure and also the consequence of failure for safety, business and the environment.