Nickel alloy · Ni-Mo-Cr-W · UNS N10276 · W.Nr. 2.4819
Hastelloy C276: the high-molybdenum workhorse of chemical plants
In short: Hastelloy C276 is a nickel alloy with 15–17% molybdenum, 14.5–16.5% chromium and 3–4.5% tungsten, and very low carbon. It resists reducing acids, chlorides and mixed chemical streams that defeat stainless steel, so it is used in reactors, scrubbers, bleach plants, pharmaceutical equipment and sour gas.
Overview
Hastelloy C276 in brief
- About 16% Mo, 15.5% Cr, 3.7% W
- Exceptional resistance to reducing acids and chlorides
- Usable in the as-welded condition
- PREN about 68–76
Alloy C276 contains about 16% molybdenum, 15.5% chromium and 3.7% tungsten, with very low carbon and silicon, so it resists grain-boundary precipitation in weld heat-affected zones. It can usually be used in the as-welded condition. It has outstanding resistance to pitting, crevice corrosion and stress corrosion cracking.
It's one of the most widely used "last resort" alloys in chemical processing, pollution control, pulp and paper, sour gas and waste treatment. Typical equipment includes reactors, heat exchangers, scrubbers, ducts, stack liners and sour-gas piping.
Available as
Hastelloy C276 product forms
Select a form for its specification, sizes and weights.
Where it's used
Industries that specify Hastelloy C276
Reading the map
Molybdenum for reducing acids, chromium for oxidisers
C276 sits at the high-molybdenum corner. That's why it handles hydrochloric and sulphuric acid mixtures and chloride-rich streams well, while C22 is chosen where oxidising species dominate.
- Reducing acids
Molybdenum and tungsten resist sulphuric, hydrochloric and phosphoric acids.[1]
- Chlorides
High resistance to pitting, crevice corrosion and chloride stress corrosion cracking.
- Mixed streams
Tolerates the upsets and contaminants that make process streams unpredictable.
Chemistry
Composition of Hastelloy C276
- UNS
- N10276
- EN / W.Nr.
- 2.4819 · NiMo16Cr15W
- Density
- 8.89 g/cm³
- PREN
- ≈ 68 – 76
| Element | Limit, % | Why it matters |
|---|---|---|
| Ni | Balance | |
| Mo | 15.0 – 17.0 | 15–17%: reducing acids and pitting |
| Cr | 14.5 – 16.5 | 14.5–16.5% |
| Fe | 4.0 – 7.0 | |
| W | 3.0 – 4.5 | 3–4.5%: adds to Mo effect |
| Co | 2.5 max | |
| C | 0.010 max | 0.010% max: weldability |
| Si | 0.08 max | |
| Mn | 1.0 max | |
| V | 0.35 max |
Limits per ASTM B575; other product forms and specifications differ slightly. Your order's specification and edition govern.
Applications
Where stainless steel runs out
Mechanical properties
Solution-annealed room-temperature values
ASTM B575 (solution-annealed): room-temperature specification values for the annealed condition.
Supply
C276 by product form
| Product form | Specification and designation |
|---|---|
| Hastelloy C276 pipes | ASTM B622 (seamless) / B619 (welded) |
| Hastelloy C276 tubes | ASTM B622 / B626 |
| Hastelloy C276 plates | ASTM B575 / ASME SB575 |
| Hastelloy C276 sheets | ASTM B575 |
| Hastelloy C276 coils | ASTM B575 |
| Hastelloy C276 bars | ASTM B574 / ASME SB574 |
| Hastelloy C276 fittings | ASTM B366 WPHC276 |
| Hastelloy C276 flanges | ASTM B564 N10276 |
| Hastelloy C276 bolts | ASTM B574 bar stock |
| Hastelloy C276 nuts | ASTM B574 |
| Hastelloy C276 washers | ASTM B575 |
- Product specification per form (B622, B575, B574, B564)
- Solution-annealed condition
- Process chemistry for a suitability check
- Matching C276 or C22-type filler
- PMI on receipt
Ordering
What to put on an order for Hastelloy C276
Getting these on the enquiry avoids the usual back-and-forth and makes sure the certificate matches your specification.
C276 questions
Answers about Hastelloy C276
Why is Hastelloy C276 so widely used?
Its 15–17% molybdenum, with chromium and tungsten, resists a very wide range of chemical environments, including reducing acids, chlorides and mixed process streams where stainless steels and lower nickel alloys fail. Haynes publishes corrosion data across many acids.[1]
C276 or C22?
C22 has more chromium (20–22.5% against 14.5–16.5%) and so resists oxidising media better; C276 has more molybdenum (15–17%) for strongly reducing conditions. Compare C276 vs C22.
C276 or Inconel 625?
625 is stronger with more chromium; C276 handles reducing acids and mixed chemical environments better. Compare 625 vs C276.
Does C276 need heat treatment after welding?
Normally no; its very low carbon and silicon limit grain-boundary precipitation in the weld heat-affected zone. Use matching filler.
Which specifications cover C276?
Pipe: ASTM B622 (seamless) / B619 (welded). Plate: ASTM B575 / ASME SB575. Bar: ASTM B574 / ASME SB574. Fittings: ASTM B366 WPHC276.
Sources
References
Hastelloy® is a trademark of Haynes International. Composition per the cited specification.
Need Hastelloy C276?
Send form, size and the process chemistry. We confirm suitability and supply with 3.1 certificates and PMI.