Hastelloy C-22 and Hastelloy C-2000 are two advanced members of the nickel–chromium–molybdenum family. C-2000 was developed after C-22 and set out to close one gap: performance in reducing acids.
The copper and tungsten choice
According to our datasheets, C-2000 has chromium at ~23% and molybdenum at ~23%; in C-22 those are 20.0–22.5% and 12.5–14.5%. In other words the molybdenum in C-2000 is nearly doubled.
The real innovation is the ~1.6% copper addition. Copper provides protection in reducing environments — especially in sulphuric acid. There is no copper in C-22.
Another difference: C-22 contains 2.5–3.5% tungsten while C-2000 contains none. C-2000 fills that gap with its high molybdenum. The iron limit differs too: 2.0–6.0% in C-22 against max 13.00% in C-2000.
The result is a corrosion alloy described in the industry as “universal”: C-2000 gives acceptable performance in both oxidising and reducing conditions, and therefore offers a single-material solution in plants where the environment is variable or uncertain.
Comparison in numbers
| PROPERTY | Hastelloy C-22 | Hastelloy C-2000 |
|---|---|---|
| Nickel (Ni) | 50 – 63% | ~59% |
| Chromium (Cr) | 20.0 – 22.5% | ~23% |
| Molybdenum (Mo) | 12.5 – 14.5% | ~23% |
| Copper (Cu) | — | ~1.6% |
| Tungsten (W) | 2.5 – 3.5% | — |
| Iron (Fe) | 2.0 – 6.0% | max 13.00% |
| Cobalt (Co) | max 2.5% | max 2.00% |
| Carbon (C) | max 0.015% | max 0.01% |
| Manganese (Mn) | max 0.5% | max 0.50% |
| Silicon (Si) | max 0.08% | max 0.08% |
| Aluminium (Al) | — | max 0.50% |
| UNS | N06022 | N06200 |
| W.Nr (DIN/EN) | 2.4602 | 2.4675 |
| EN chemical symbol | NiCr21Mo14W | NiCr23Mo16Cu |
Values are taken from our product datasheets; section thickness and the applied heat treatment regime change the result.
Which one, and when?
Hastelloy C-22 is preferred — predominantly oxidising processes, nitric + hydrofluoric mixtures, wet chlorine environments, pharmaceutical reactors, flue gas systems. It is easier to source and more widely available; it can be called out by the aerospace specification AMS 5766.
Hastelloy C-2000 is required — sulphuric acid processes, mixed acid environments, plants where conditions change within the process, multi-purpose chemical reactors. Where a single material has to meet both oxidising and reducing conditions.
The other members of the family
For purely reducing environments (especially hydrochloric acid) there is Hastelloy B-3; for the classic molybdenum-weighted option, see our Hastelloy C-276 – C-22 comparison.
Technical datasheets
Hastelloy C-22 — chemical composition, mechanical values, standard equivalents
Hastelloy C-2000 — chemical composition, mechanical values, standard equivalents
Both grades are supplied to order in round bar, flat bar, plate, sheet, pipe and forged forms. Contact us for a quotation.