General attack corrosion can be recognized by which surface characteristics?

• A. Roughening of the surface and presence of corrosion products.
• B. Uniform color change with no surface roughness.
• C. Pitting and discrete holes in localized areas.
• D. No visible surface changes; only subsurface damage.

Answer: (A)

General attack corrosion manifests as a uniform deterioration across the exposed surface, so you typically see the surface become rough and covered with corrosion products (like rust or scale). This reflects material loss happening evenly over the area, rather than isolated spots. The other descriptions point to different patterns: a smooth surface with only color change isn’t showing the roughness and oxide buildup typical of general attack; pits and discrete holes indicate localized corrosion; and no visible surface changes with subsurface damage means the surface looks fine even though damage is below. So the combination of a rough surface and visible corrosion products best identifies general attack corrosion.