Recognize the location and mechanism of corrosion damage
- Pitting corrosion
A localized cavity extends into the surface. Confirm the material condition and actual exposure rather than using appearance as a resistance test.
- Crevice corrosion
The sheltered gap changes the local environment. Check trapped liquid, drainage and the assembled interface geometry.
- DezincificationThis term
Selective removal of zinc can leave a weakened porous region in susceptible brass. Check alloy and water chemistry for the actual exposure.
- Stress corrosion cracking (SCC)
Cracking combines a susceptible material, tensile stress and the relevant environment. A salt-spray result does not establish immunity.
- Sensitization
The marked grain boundary represents a susceptible metallurgical condition. Heat history and alloy condition require separate evaluation.
A pit, a sheltered crevice, selective zinc loss, stress-assisted cracking and a susceptible grain boundary show different degradation routes. An intact-looking surface can conceal local damage.
Exaggerated material sections, not corrosion predictions. Alloy condition, chemistry, stress and exposure must be assessed for the actual component.