321 Stainless Steel Surface Treatment & Coating

1. What is passivation for 321? Nitric acid treatment removes contaminants and strengthens the oxide layer.

2. Is pickling necessary after welding 321? Yes, to remove weld scale and restore surface corrosion resistance.

3. Can 321 be electro-polished? Yes, electro-polishing creates a smooth, corrosion-resistant surface.

4. What coatings are suitable for 321? Ceramic coatings for extreme temperatures; no need for anti-corrosion coatings in most cases.

5. How often to re-passivate 321? Every 1-3 years in harsh environments, depending on exposure.