If there is severe general corrosion, usually SCC will not occur, however when the corrosion products are trapped so as to cause stress in the structure, what will occur?

• A. Stress corrosion cracking
• B. Uniform thinning without cracking
• C. Pitting corrosion
• D. Galling

Answer: (A)

Stress corrosion cracking happens when a corrosive environment and tensile or residual stress are present together, causing cracks to form and grow. If general, severe corrosion produces corrosion products that trap and create local stress or a crevice, that combination can initiate and propagate cracking along the metal’s microstructure. In that scenario, the material is weakened not just by loss of cross-section but by crack growth driven by the environment and stress.

The other forms don’t fit this situation. Uniform thinning is just general corrosion reducing thickness without cracks. Pitting is localized metal loss forming pits but not necessarily crack formation from stress. Galling is a wear-related adhesion and surface seizure, not a corrosion-driven cracking mechanism.