Chemical plant flanges operate under the most diverse corrosion environments in industry. From caustic service (NaOH 30-50%) requiring nickel-rich alloys, to sulfuric acid concentration stages demanding Alloy 20 or Hastelloy, to hydrochloric acid where only fluoropolymers or titanium survive. This page catalogs the materials, certifications, and surface treatments we supply for chemical processing applications.
| Application | Specification |
|---|---|
| Sulfuric Acid Concentrator (98%) | ASME B16.5 Class 150, Hastelloy C276, RF facing |
| Caustic Evaporator (50% NaOH, 150°C) | ASME B16.5 Class 300, Nickel 201, RF |
| Nitric Acid Absorber Tower | ASME B16.5 Class 150, Alloy 20 (Carpenter 20), RF |
| Pharmaceutical CIP Skid (sanitary) | ASME B16.5 Class 150, 316L Ra ≤0.8µm, electropolished |
| Hydrochloric Acid Storage Tank Inlet | ASME B16.5 Class 150, PTFE-lined carbon steel |
| Phosphoric Acid Reactor (75% P₂O₅) | ASME B16.5 Class 300, Alloy 20 or 316L clad |
For 98% sulfuric acid at moderate temperatures, Alloy 20 (Carpenter 20Cb-3) is the standard workhorse material. For higher temperatures (120°C+), upgrade to Hastelloy C276. For lower concentrations (60-80%), 316L can work but is not preferred. We supply all three with full ASTM A262 intergranular corrosion test certification.
Yes. We supply PTFE-lined, PFA-lined, and glass-lined carbon-steel flanges for HCl service. Lining thickness typically 3-5 mm. Working temperature limits: PTFE to 200°C, PFA to 260°C, glass to 180°C (with thermal shock risk). Lead time is 6-8 weeks for lined flanges.
For pharmaceutical / biotech service per ASME BPE: mechanical polish to Ra ≤ 0.8 µm (32 µin) is standard. Electropolish to Ra ≤ 0.4 µm (16 µin) is available for ultra-sanitary applications. We certify surface finish with a profilometer trace per batch. Documentation includes BPE compliance certificate.
Every Alloy 20 order includes PMI (positive material identification) using XRF analyzer at our mill before shipment. PMI result is logged on the MTC 3.1. We also perform ASTM A262 Practice E intergranular corrosion test to verify the nickel-chromium-molybdenum-copper composition is in spec. Visual appearance and weight are NOT sufficient — PMI is mandatory.
Quick contact options for sourcing pipe flanges (ASME B16.5 / EN 1092-1 / JIS B2220 / BS 4504 / HG/T 20592) with full material traceability and shipping to 60+ countries.