Which condition promotes stress corrosion cracking?

• A. Chloride-containing environments, tensile stress, and susceptible alloys.
• B. Zero tensile stress and non-chloride environment.
• C. Only high temperature without chemical species.
• D. Completely inert environment.

Answer: (A)

Stress corrosion cracking happens when three things align: a material that is vulnerable to cracking, a corrosive environment, and tensile stress. Chloride ions are particularly aggressive because they can destabilize protective films on metals and promote localized attack, such as pitting, which under tensile loading can grow into a crack. So the best option is the one that includes a chloride-containing environment, the presence of tensile stress, and a susceptible alloy, because all three factors together enable the crack to initiate and propagate in a corrosive, stressed metal.

Without tension, cracks won’t propagate even if the environment is aggressive. A non-chloride environment reduces the likelihood of SCC in chloride-susceptible alloys. High temperature by itself, without a chemical species driving corrosion, wouldn’t cause SCC. An inert, non-corrosive environment also cannot support SCC.