Hastelloy® C-22 (UNS N06022)
Hastelloy® C-22 is a versatile nickel - chromium - molybdenum - tungsten alloy designed for superior resistance to an even broader range of corrosive media than its predecessor, C-276. By optimizing the chromium and molybdenum content, C-22 provides exceptional defense against both oxidizing and reducing chemicals. It is particularly effective in resisting "pitting," crevice corrosion, and stress-corrosion cracking in aggressive environments containing chlorides and other halides.
At Aries Alloys, we supply Hastelloy C-22 to industries that operate "multi-purpose" chemical plants where the process chemistry can change frequently. Our C-22 inventory is chosen for its ability to protect equipment against the most unpredictable and aggressive chemical cocktails.
Advanced Performance Attributes
- Superior Oxidizing Resistance: The higher chromium content (22%) compared to C-276 provides significantly better protection against oxidizing environments, such as nitric acid or wet chlorine.
- Universal Chemical Defense: Outstanding resistance to a wide variety of chemical process environments, including strong oxidizers like ferric and cupric chlorides, and reducing agents like sulfuric acid.
- Unmatched Weldability: Excellent resistance to the formation of grain-boundary precipitates in the weld heat-affected zone, making it suitable for most chemical process applications in the as-welded condition.
- Pitting & Crevice Immunity: The synergy of chromium, molybdenum, and tungsten ensures the alloy remains passive in stagnant or low-flow chloride solutions.
- Thermal Versatility: Maintains integrity in environments ranging from cryogenic temperatures up to 1250° F (677° C).
Technical Insights & Data
The Chromium-Molybdenum Synergy: The secret to C-22’s versatility is the precise balance of Chromium (20-22.5%) and Molybdenum (12.5-14.5%). This combination allows the material to handle oxidizing acids that would degrade Molybdenum-heavy alloys, while still providing the defense needed against reducing acids.
Mechanical Capabilities:
- Density: 8.69 g/cm3
- Tensile Strength: 100,000 psi (690 MPa)
- Elongation: 45%, allowing for excellent cold-forming and complex fabrication.
- Non-Magnetic: Remains non-magnetic across all processing stages.
Primary Industrial Use Cases
Aries Alloys is a preferred supplier of Hastelloy C-22 for high-purity and high-risk applications:
- Pharmaceutical Industry: Reactors, heat exchangers, and centrifuges where high-purity and easy-to-clean surfaces are essential.
- Agrochemical Production: Equipment used for the synthesis of pesticides and fertilizers involving aggressive halides.
- Nuclear Waste Processing: Containment vessels and piping for radioactive waste where long-term corrosion resistance is mandatory.
- Power Plant FGD Systems: Components exposed to aggressive flue gases, particularly in scrubbers and chimney liners.
- Cellulose Processing: Bleaching and digestion equipment in advanced pulp and paper mills.
Available Product Forms at Aries Alloys
We stock and distribute Hastelloy C-22 in accordance with ASTM B574, B575, and B622:
- Seamless Piping: High-precision tubes for volatile chemical transfer and pharmaceutical lines.
- Sheets & Plates: Precision-cut flat products for the fabrication of tanks and scrubber vessels.
- Round & Hex Bars: Ideal for machining acid-resistant bolts, stems, and pump shafts.
- Forged Components: Custom flanges and elbows designed for leak-proof, corrosion-resistant connectivity.