Fayed surfaces cause concern in chemical cleaning because of the danger of

• A. Hydrogen embrittlement
• B. Thermal expansion
• C. Entrapping corrosive materials
• D. Scratches on surface

Answer: (C)

Fayed surfaces create crevices where cleaning solution can collect and drain slowly. In chemical cleaning, residual cleaners in those tight gaps can stay in contact with the metal, promoting localized attack and corrosion after the cleaning process. That’s why the main concern is entrapping corrosive materials in the joints and undercuts. Hydrogen embrittlement is more about hydrogen entering the metal from other processes, thermal expansion isn’t driven by this geometry, and surface scratches aren’t the specific risk tied to these crevices in chemical cleaning.