Hastelloy C-276 (UNS N10276) and Hastelloy C-22 (UNS N06022) are the two most specified nickel-chromium-molybdenum alloys for aggressive chemical service. Both are supplied to ASTM B575 — so how do you choose?
Composition at a Glance
| Element (%) | C-276 | C-22 |
|---|---|---|
| Chromium | 14.5 – 16.5 | 20.0 – 22.5 |
| Molybdenum | 15.0 – 17.0 | 12.5 – 14.5 |
| Tungsten | 3.0 – 4.5 | 2.5 – 3.5 |
| Iron | 4.0 – 7.0 | 2.0 – 6.0 |
The Practical Difference
- C-276 (higher Mo+W) is stronger in reducing media — hydrochloric and sulfuric acids at moderate concentrations.
- C-22 (higher Cr) performs better in oxidizing media — wet chlorine, hypochlorite, ferric chloride and nitric-acid mixtures.
- Both resist pitting and crevice corrosion in hot chloride solutions and both are used in the as-welded condition.
Rule of Thumb
Mixed or unpredictable chemistry? C-22 is usually the safer blanket choice — which is why many pharmaceutical and multipurpose plants standardize on it. For dedicated reducing-acid service, C-276 remains the workhorse. See C-276 sheet & plate and C-22 sheet & plate for stock sizes.
Tailan Metal supplies nickel alloy sheet and plate in Inconel, Incoloy, Monel, Hastelloy and super-austenitic grades. For a quotation contact sales@tailanmetal.com or WhatsApp +86-18621377760.
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