Hastelloy C276: properties, composition, uses and standards
Hastelloy C276 is a nickel–molybdenum–chromium alloy with tungsten, chosen for the most aggressive mixed acids, wet chlorine and hypochlorite. UNS N10276, W.Nr 2.4819, PREN ≈ 68, density 8.89 g/cm³.
What is Hastelloy C276?
Hastelloy C276 is a nickel–molybdenum–chromium alloy with tungsten. Engineers choose it for the most aggressive mixed acids, wet chlorine and hypochlorite. It is also known as Alloy C-276, UNS N10276, W.Nr 2.4819, Nicrofer 5716.
- UNS
- N10276
- W.Nr
- 2.4819
- EN
- NiMo16Cr15W
- Trade names
- Hastelloy C-276 · Nicrofer 5716
- Density
- 8.89 g/cm³
- Melting range
- 1323 – 1371 °C
- Magnetic
- Non-magnetic
- PREN (approx.)
- ≈ 68
Chemical composition and what each element does
| Element | Weight % |
|---|---|
| Nickel | Balance |
| Molybdenum | 15.0 – 17.0 |
| Chromium | 14.5 – 16.5 |
| Iron | 4.0 – 7.0 |
| Tungsten | 3.0 – 4.5 |
| Cobalt | 2.5 max |
| Carbon | 0.010 max |
| Manganese | 1.0 max |
| Vanadium | 0.35 max |
| Silicon | 0.08 max |
Per ASTM B575 for UNS N10276.
Very high molybdenum handles hydrochloric and sulphuric acid where other alloys fail.
Chromium adds resistance to oxidising acids, wet chlorine and hypochlorite.
Tungsten further improves pitting and crevice resistance.
Very low carbon and silicon let C276 be used as-welded.
Mechanical properties
| Property | Value |
|---|---|
| Tensile strength | 690 MPa · 100 ksi |
| Yield strength 0.2% | 283 MPa · 41 ksi |
| Elongation | 40% |
Solution-annealed plate & sheet, minimum values. Values for pipe, bar and forgings differ slightly — see the product standard.
Where Hastelloy C276 is used
- Chemical processing. Reactors, heat exchangers and piping for mixed acids. Industry →
- Flue-gas desulphurisation. Scrubbers, dampers and stack liners. Industry →
- Pharmaceutical. Reactors handling chlorinated compounds. Industry →
- Pulp & paper. Bleach plants. Industry →
- Sour gas. Downhole and surface equipment in severe H₂S. Industry →
Welding C276
The matching filler is ERNiCrMo-4 (AWS A5.14). ENiCrMo-4 electrode.
Keep heat input moderate and interpass temperature low, clean joints thoroughly, and pickle or passivate after welding where the service is corrosive.
Hastelloy C276 compared with similar grades
| Grade | PREN | Choose it for |
|---|---|---|
| Hastelloy C276 | ≈ 68 | The most aggressive mixed acids, wet chlorine and hypochlorite |
| Inconel 625 | ≈ 51 | Seawater, high strength and high temperature in one alloy |
| Hastelloy C22 | ≈ 65 | Mixed oxidising and reducing acids, and weld overlays |
| Super Duplex 2507 | ≈ 42 | Seawater and high-chloride service where strength also matters |
Hastelloy C276 standards by product
| Product | Standard |
|---|---|
| Hastelloy C276 sheet | ASTM B575 |
| Hastelloy C276 plate | ASTM B575 |
| Hastelloy C276 coil | ASTM B575 |
| Hastelloy C276 pipe & tube | ASTM B622 · ASTM B619 |
| Hastelloy C276 fittings | ASTM B366 WPHC276 · ASTM B462 / B564 |
| Hastelloy C276 flanges | ASTM B462 / B564 |
| Hastelloy C276 fasteners | ASTM B574 |
Buying Hastelloy C276: what to specify
- The product standard and the UNS or designation — for example ASTM B575 UNS N10276.
- Size, thickness or schedule, and quantity in pieces and kg or metres.
- Heat-treatment condition where the standard offers a choice.
- Certificate: EN 10204 3.1 as standard, 3.2 if a third party must witness.
- NACE MR0175 / ISO 15156 compliance if the service contains H₂S.