A Review of the Concept of Mildly Sour Environments

Published data on the effects of different levels of hydrogen sulphide (H₂S) and pH in aqueous environments on steels have been reviewed. Both sulphide stress corrosion cracking (SSCC) and hydrogen pressure induced cracking (HPIC) have been considered. The data have been collated and presented on one diagram, and the appropriateness of setting relaxed hardness controls for ‘mildly sour’ environmental conditions has been discussed.