Stress corrosion cracking occurs under which combination of conditions?

Stress corrosion cracking occurs under which combination of conditions?

• A. High tensile stress, a corrosive environment, and susceptible materials
• B. Low temperature, inert environment, and strong materials
• C. Absence of aggressive species and compressive stress
• D. High humidity only

Answer: (A)

Stress corrosion cracking happens when three conditions line up at once: the material must be susceptible to SCC, the environment must be corrosive to that material, and there must be a sustained tensile (pulling) stress acting on the part. The corrosion and the mechanical load interact at the crack tip, so tiny cracks can form and then grow under the combined effects of chemical attack and opening stress. If any one of these elements is missing, SCC is unlikely: an inert environment won’t promote the electrochemical reactions at the crack tip; a compressive or zero stress won’t keep a crack open and propagate; and a non-susceptible material may resist cracking even in a corrosive medium under stress. The combination described—a susceptible alloy, a corrosive environment, and high tensile stress—is what enables stress corrosion cracking to initiate and advance.

Stress corrosion cracking happens when three conditions line up at once: the material must be susceptible to SCC, the environment must be corrosive to that material, and there must be a sustained tensile (pulling) stress acting on the part. The corrosion and the mechanical load interact at the crack tip, so tiny cracks can form and then grow under the combined effects of chemical attack and opening stress. If any one of these elements is missing, SCC is unlikely: an inert environment won’t promote the electrochemical reactions at the crack tip; a compressive or zero stress won’t keep a crack open and propagate; and a non-susceptible material may resist cracking even in a corrosive medium under stress. The combination described—a susceptible alloy, a corrosive environment, and high tensile stress—is what enables stress corrosion cracking to initiate and advance.