Hastelloy C22 Tubes and Fittings
Hastelloy® C-22® Tube, UNS N06022
Super Alloys™ range – Tubes and fittings for extremely corrosive fluids in hygienic environments
The C-22 range is designed for fluids where super-austenitic alloys such as AL-6XN reach their limits:
mixed oxidising and reducing acids, hot chlorinated seawater, dilute hydrochloric acid, chloride-laden sulphuric acid, concentrated bleach, severe H₂S + Cl⁻ environments.
Used in high-purity biopharmaceuticals, fine chemicals, flue gas treatment, personal care, and very high-acidity food processing.
Surface finishes and hygienic classes
| Finish | ASME BPE code | Internal Ra | External Ra |
| Mechanically polished | SF1 | ≤ 0.51 µm (20 µin) | ≤ 0.81 µm |
| Electropolished | SF5 | ≤ 0.51 µm (20 µin) | ≤ 0.81 µm |
| Electropolished | SF6 | ≤ 0.64 µm (25 µin) | ≤ 0.81 µm |
Compliant with ASME BPE for codes SF1, SF5 and SF6. C-22 is recognised by ASME BPE and accepted for pharmaceutical applications.
Material
Hastelloy C-22® nickel-based alloy (UNS N06022, EN 2.4602).
Typical composition:
Ni: 56 % | Cr: 20 – 22.5 % | Mo: 12.5 – 14.5 % | W: 3 % | Fe: ≤ 3 % | Co: ≤ 2.5 % | C: ≤ 0.01 %.
PREN above 70, versus 45 for AL-6XN and 24 for 316L.
Nickel-based austenitic, non-magnetic microstructure.
Weldability
During fusion, molybdenum and tungsten segregate and the weld root becomes the weak point for corrosion. This is offset by using a matching-grade filler metal, type ERNiCrMo-10 (AWS A5.14, ISO Ni Cr 21 Mo 14 W).
Heat input must remain limited to prevent precipitation of embrittling intermetallic phases between 600 and 1000 °C.
In multi-pass welding, the interpass temperature must drop below 100 °C before starting the next pass, checked with a temperature-indicating crayon or pyrometer.
Purge gas is maintained throughout cooling to prevent internal oxidation of the weld
Dimensional standards
Diameters from 1/4″ (6.35 mm) to 4″ (101.6 mm), wall thicknesses 0.89 mm to 2.11 mm.
Welded tubes compliant with ASTM B626 and ASME SB626. Seamless tubes compliant with ASTM B622 and ASME SB622.
Traceability and packaging
Each tube is supplied with its 3.1 material certificate according to EN 10204.
Full-length marking on the OD: grade, heat number, batch, dimensions.
Polished and electropolished tubes are supplied in individual polyethylene sleeves, with ends
capped.
Lengths from 2 m.
Contact us directly for any enquiry.