Hastelloy C-22 · UNS N06022 · W. Nr. 2.4602 · NiCr21Mo14W · Alloy 22
Hastelloy C-22 (N06022): composition, properties, fittings and flanges
Hastelloy C-22 (UNS N06022, W. Nr. 2.4602) is a Ni-Cr-Mo-W alloy with a higher chromium content than C-276, at 20.0-22.5 %, combined with 12.5-14.5 % molybdenum and 2.5-3.5 % tungsten. Raising the chromium improves resistance to oxidising environments while molybdenum and tungsten preserve resistance to reducing media, giving…
- UNS
- N06022
- W. Nr.
- 2.4602
- Density
- 8.69 g/cm³ (0.314 lb/in³)
- Key strength
- 690 MPa / 100 ksi
Identification and standards
| Short form | Hastelloy C-22 · UNS N06022 · W. Nr. 2.4602 · NiCr21Mo14W · Alloy 22 |
|---|---|
| Classification | Ni-Cr-Mo-W alloy with broadly balanced oxidation and reduction resistance |
| UNS | N06022 |
| Werkstoff number | 2.4602 |
| Material family | Hastelloy Alloys |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Nickel (Ni) | Balance | Matrix |
| Chromium (Cr) | 20.0 - 22.5 | Oxidising media resistance |
| Molybdenum (Mo) | 12.5 - 14.5 | Reducing media and pitting resistance |
| Tungsten (W) | 2.5 - 3.5 | Additional localised corrosion resistance |
| Iron (Fe) | 2.0 - 6.0 | - |
| Cobalt (Co) | 2.50 max | - |
| Vanadium (V) | 0.35 max | - |
| Manganese (Mn) | 0.50 max | - |
| Silicon (Si) | 0.08 max | - |
| Carbon (C) | 0.015 max | - |
| Phosphorus (P) | 0.020 max | - |
| Sulphur (S) | 0.020 max | - |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (annealed plate, ASTM B575) | 690 MPa / 100 ksi |
|---|---|
| 0.2 % yield strength, min | 310 MPa / 45 ksi |
| Elongation in 2 in, min | 45 % |
| Typical hardness, annealed | 180 - 220 HB |
| Typical pitting resistance equivalent number | About 65 - 70 |
| Practical service temperature range | -198 °C to about 650 °C in process service |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 8.69 g/cm³ (0.314 lb/in³) |
|---|---|
| Melting range | 1357 - 1399 °C (2475 - 2550 °F) |
| Modulus of elasticity | 206 GPa (29.9 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 10.1 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 11.8 µm/m·°C |
| Electrical resistivity at 20 °C | 1.28 µΩ·m |
Specifications by product form
| Plate / sheet / strip | ASTM B575 / ASME SB-575 |
|---|---|
| Bar / rod / wire | ASTM B574 / ASME SB-574 |
| Seamless pipe & tube | ASTM B622 / ASME SB-622 |
| Welded pipe & tube | ASTM B619 / B626 |
| Forgings & flanges | ASTM B564 / ASME SB-564 (UNS N06022) |
| Butt weld fittings | ASTM B366 / ASME SB-366 (WP22 / WPHC22) |
| Welding consumables | ERNiCrMo-10 wire, ENiCrMo-10 electrode |
| UNS / EN / China | UNS N06022 · EN NiCr21Mo14W · W. Nr. 2.4602 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Plate, sheet and strip
- Seamless pipe and tube
- Forged blanks, rings and flanges to ASME B16.5 / B16.47
- Butt weld elbows, tees, reducers and stub ends to ASME B16.9
- Machined reactor internals and vessel nozzles
Typical applications
- Flue gas desulphurisation absorber towers, outlet ducts and dampers
- Multipurpose chemical reactors handling batch-to-batch chemistry swings
- Pharmaceutical and agrochemical synthesis with halogenated intermediates
- Nuclear high-level waste containers and repository packaging
- Pulp bleach plants and chlorine dioxide generators
- Pickling lines handling mixed nitric-hydrofluoric acid
- Deep sour gas wells and geothermal systems with mixed chloride and sulphide brines
Welding, forming and machining
- Welding
- Use ERNiCrMo-10 filler with controlled heat input and interpass temperature below 100 °C. Unlike older C-family alloys, C-22 retains as-welded corrosion resistance across a wide chemistry range.
- Hot forming
- Solution anneal at 1120-1165 °C followed by water quench. Avoid lingering in the 550-1050 °C window, which can precipitate mu and sigma phases and lower toughness.
- Machining
- Similar to C-276: rigid setups, carbide tooling, low cutting speed and never allow the tool to dwell.
- Cleaning
- Descale by abrasive blasting then acid pickle. Ensure complete removal of sulphur, lead, phosphorus and other low-melting-point metals before welding or high-temperature service.
Buy Hastelloy C-22 from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.