NiMo16Cr15W · N10276 · Hastelloy C-276 · ASTM B366
The broadest corrosion resistance of any commercial alloy — PRE ~70. 16% Mo + W provides exceptional resistance to reducing acids, pitting, and crevice corrosion. The material of last resort for the most aggressive chemical environments.
Hastelloy C-276 (UNS N10276, EN 2.4819) is the most widely used high-performance nickel alloy in the chemical process industry. Its combination of ~16% Mo, ~15% Cr, and ~4% W delivers exceptional resistance across reducing acid environments — concentrated HCl, H₂SO₄, HF mixtures, acetic acid, and formic acid. The tungsten stabilises the matrix against localised attack that Mo alone cannot prevent.
The principal limitation compared to C-22 is in oxidising environments: C-276's lower chromium (15–17%) means it is less resistant to strongly oxidising acids (concentrated HNO₃, concentrated H₂SO₄ at elevated temperature, hypochlorite) than the higher-Cr C-22 grade. For environments that alternate between oxidising and reducing conditions, C-22 (2.4602) is the safer specification.
| Element | Min | Max | Role |
|---|---|---|---|
| Nickel (Ni) | Balance | — | Matrix, toughness |
| Chromium (Cr) | 14.5% | 16.5% | Passivation |
| Molybdenum (Mo) | 15.0% | 17.0% | Primary pitting resistance |
| Tungsten (W) | 3.0% | 4.5% | Enhanced crevice corrosion resistance |
| Iron (Fe) | 4.0% | 7.0% | — |
| Carbon (C) | — | 0.010% | Very low — weld sensitisation prevention |
| EN number | 2.4819 |
| EN designation | NiMo16Cr15W |
| UNS | N10276 |
| Trade name | Hastelloy C-276 |
| PRE (typical) | ~70 |
| Filler (GTAW) | ERNiCrMo-4 |
| PWHT | Not required |
| Standard | ASTM B366; dimensions to ASME B16.9 (EN 10253 does not cover nickel alloys) |
| Certificate | EN 10204 3.1 standard |
PMI (XRF) on every C-276 order. EN 10204 3.1 standard. Tell us your acid concentration, temperature, and fitting schedule.
Get QuoteDN15–DN600 and larger. Outside diameters follow the EN 10220 / EN ISO 1127 pipe series; wall thickness is matched to your connecting pipe.
| Size | OD (mm) |
|---|---|
| DN 15 | 21.3 |
| DN 20 | 26.9 |
| DN 25 | 33.7 |
| DN 32 | 42.4 |
| DN 40 | 48.3 |
| DN 50 | 60.3 |
| DN 65 | 76.1 |
| DN 80 | 88.9 |
| DN 100 | 114.3 |
| DN 125 | 139.7 |
| DN 150 | 168.3 |
| DN 200 | 219.1 |
| DN 250 | 273.0 |
| DN 300 | 323.9 |
| DN 350 | 355.6 |
| DN 400 | 406.4 |
| DN 450 | 457.0 |
| DN 500 | 508.0 |
| DN 600 | 610.0 |
C-276 (2.4819) is preferred for predominantly reducing environments — concentrated HCl, reducing mineral acids, strongly reducing mixed media. C-22 (2.4602) has higher chromium (21% vs 16%) and is the better choice when the environment is mixed oxidising and reducing, or predominantly oxidising — such as FGD scrubbers with simultaneous H₂SO₄ and hypochlorite, or wet chlorine gas. If in doubt about the oxidising/reducing balance of the process, C-22 is the more conservative choice.
ERNiCrMo-4 filler for GTAW; PWHT is not required.
It has a PRE of about 70, with 16% molybdenum plus tungsten for exceptional resistance to reducing acids, pitting and crevice corrosion.
