Chemical Processing
Corrosion-Resistant PVF for Chemical Service
Chemical plant flanges across acid, caustic, and chloride service. Stainless, duplex, and nickel alloys to match the specific corrosion environment.
Sulfuric acid service runs in Inconel 825 for concentrated acid and Hastelloy C-276 for dilute mixed acid. Phosphoric acid uses duplex 2205 and 2507. Hydrochloric acid usually means Hastelloy or pure tantalum at the most extreme. The selection is a function of acid concentration, temperature, and any oxidizing impurities.
Caustic service runs in carbon steel at room temperature and shifts to nickel alloys above 200 degrees F. Stress corrosion cracking is the main failure mode. Chloride service is a stainless killer; F316L holds at ambient temperatures but pits and cracks above 140 degrees F in dilute chloride. Duplex 2205 buys headroom; super duplex 2507 buys more.
Documentation includes PMI on every flange face for grade verification, MTR with chemistry, and corrosion test reports where the project specifies pitting (ASTM G48) or stress corrosion (NACE TM0177) data.
Common Standards
- ASME B16.5
- NACE MR0175
- NACE TM0177
Common Materials
- F316L
- Duplex 2205
- Super duplex 2507
- Inconel 625
- Inconel 825
- Hastelloy C-276
- Titanium