Hastelloy C276 Tube Sheet
The specialist's specialist — high molybdenum and tungsten content give C276 resistance to both oxidizing and reducing acid environments at once, a combination that neither stainless, duplex, nor most single-purpose alloys can match.
Chemical Composition
| Element | Min % | Max % |
|---|---|---|
| Nickel (Ni) | Balance | — |
| Molybdenum (Mo) | 15.0 | 17.0 |
| Chromium (Cr) | 14.5 | 16.5 |
| Tungsten (W) | 3.0 | 4.5 |
| Iron (Fe) | 4.0 | 7.0 |
| Carbon (C) | — | 0.01 |
Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 690 MPa min (annealed) |
| Yield Strength (0.2% offset) | 283 MPa min (annealed) |
| Elongation | 40% min |
| Max. Practical Service Temp. | ~550°C |
Equivalent Grades
| Standard | Designation |
|---|---|
| ASTM / UNS | N10276 |
| EN / DIN | 2.4819 |
| Trade Name | Hastelloy® C-276 (Haynes International) |
The grade designation and product-form cross-reference separates UNS N10276 and EN 2.4819 from the ASTM/ASME specifications used for plate, sheet or forgings.
Why C276 Over Other Alloys
Purchasing Specifications by Form
For Hastelloy C276 / UNS N10276, plate/sheet/strip purchasing leads with ASTM B575. Forging uses ASTM B564 where listed. ASTM B622 covers seamless pipe and tube — it is not a plate specification.
| Element | Reference |
|---|---|
| Common name | Hastelloy C276 |
| UNS | N10276 |
| Plate / sheet / strip | ASTM B575 (SB-575 where applicable) |
| Forging | ASTM B564 (SB-564 where applicable) |
| Pipe / tube | ASTM B622 — not plate |
B575, B564 and B622 are form-scoped. Confirm plate vs forging vs clad face on the RFQ. ASME SB-* may apply by form and Code context.
| Specification | Product form / role | How to read it for tube sheets |
|---|---|---|
| ASTM B575 / SB-575 | Plate, sheet and strip | Lead plate path for solid or clad-face tube-sheet blanks from flat product |
| ASTM B564 / SB-564 | Nickel-alloy forgings (N10276 where listed) | Forged blank path when forging is specified on the drawing / PO |
| ASTM B622 | Seamless pipe and tube | Not plate. Do not treat B622 as a tube-sheet plate purchasing specification |
Useful information to include in an RFQ (not mandatory for every enquiry):
- Alloy / grade (Hastelloy C276) and UNS (N10276)
- Plate (B575) vs forging (B564) vs clad face — never treat B622 as plate TS
- Tube-sheet OD / dimensions / thickness
- Tube OD, pitch, hole diameter and pattern
- Drawing + revision, quantity, machining tolerance, inspection / testing
Continue from grade identity into product form and machining:
Available Product Forms
C276 is most often specified as a Clad Tube Sheet face over a lower-cost base, given its high per-kilogram cost, or solid for smaller, highest-criticality components.
Applications
Chemical processing involving mixed or variable acid streams, pulp and paper bleach plant service, flue gas desulfurization, and pharmaceutical processes with aggressive cleaning-in-place chemistries. See Industries for sector context.
Advantages & Limitations
Advantages
- Resists both oxidizing and reducing acid environments
- Excellent resistance to pitting and crevice corrosion
- Good weldability without post-weld heat treatment
Limitations
- Highest cost of the commonly specified corrosion-resistant alloys
- Slow, tool-intensive machining
- Often over-specified where a targeted alloy would suffice more cheaply
FAQ
It's a reasonable conservative choice given its broad resistance, but "unsure of the chemistry" is itself worth resolving before ordering — a proper fluid analysis often reveals that a less expensive targeted material (stainless, duplex, or Monel) is entirely adequate and C276 is unnecessary spend.
Both are broadly similar in application; C22 offers somewhat better resistance to certain oxidizing conditions and improved weldability in some services, while C276 has a longer track record and broader availability. The choice is often driven by specific project history and specification precedent as much as pure technical differentiation.
Given its specialist demand profile, C276 is typically sourced to order. Send your specification, quantity, and required lead time for a confirmed schedule.