Which corrosive media is listed as promoting stress corrosion cracking?

• A. Caustic with carbon steel
• B. Ammonia with copper alloys
• C. Chlorides with stainless steel
• D. Hydrochloric acid with aluminum

Answer: (C)

Stress corrosion cracking happens when a susceptible metal is exposed to a specific corrosive medium while under tensile stress. For stainless steels, chloride ions are especially aggressive because they disrupt the protective passive film that normally shields the metal, allowing localized attack to link into a crack that can grow under stress. This combination—chlorides plus stainless steel—is a classic and well-documented SCC scenario, especially at elevated temperatures or in concentrated solutions. The other pairings are more often associated with other forms of degradation (such as caustic cracking in carbon steel or general corrosion in acids) rather than the classic chloride-induced SCC of stainless steel. So, the media that promotes stress corrosion cracking with the given material is chlorides with stainless steel.