The correct answers are A (Stress Corrosion Cracking) and C (Pitting Corrosion) because both are well-known chloride-induced damage mechanisms affecting austenitic stainless steels, as emphasized in CCPS Mechanical Integrity guidance. Chloride ions are particularly aggressive toward the passive oxide layer that protects stainless steel. When this protective film is locally broken down, pitting corrosion occurs, leading to highly localized attack that can penetrate deeply while leaving most of the surface intact. This makes detection difficult and increases the likelihood of sudden failure.
Additionally, chloride stress corrosion cracking (SCC) occurs when tensile stress (residual or applied), a susceptible material (such as austenitic stainless steel), and a corrosive chloride environment are present simultaneously. This mechanism can lead to brittle, catastrophic cracking with little prior warning, which is why CCPS highlights it as a critical degradation mechanism in process equipment.
Galvanic corrosion (B) requires two dissimilar metals electrically connected in an electrolyte and is not specifically caused by chloride exposure alone. Uniform corrosion (D) is a general material loss across the surface and is not the primary concern for stainless steels in chloride environments, where localized attack dominates.
Proper Mechanical Integrity programs per CCPS require identification of such damage mechanisms, material selection, inspection strategies, and monitoring to prevent unexpected failures.
