Materials / Nickel alloy
Incoloy 825
- UNS
- N08825
- W.Nr
- 2.4858
- EN
- NiCr21Mo
A titanium-stabilised nickel-iron-chromium alloy with copper and molybdenum, engineered for both oxidising and reducing acids at a materially lower cost than the C-family alloys.
Composition
| Element | Min | Max |
|---|---|---|
| Ni | 38.0 | 46.0 |
| Cr | 19.5 | 23.5 |
| Fe | 22.0 | — |
| Mo | 2.5 | 3.5 |
| Cu | 1.5 | 3.0 |
| Ti | 0.6 | 1.2 |
| Mn | — | 1.0 |
| C | — | 0.05 |
| Al | — | 0.2 |
Per cent by weight, to the governing standard.
- Ni42.0
- Fe30.3
- Cr21.5
- Mo3.0
- Cu2.3
- Ti0.9
Per cent by weight, at the midpoint of each specified window. Elements given only as a maximum have no midpoint to take, so they sit inside the balance rather than being estimated; trace elements below 0.5 % are not shown. Indicative only; the composition table above and the governing standard are what define the limits.
Mechanical
- Tensile strength, min
- 586 MPa
- Yield strength (0.2%), min
- 241 MPa
- Elongation, min
- 30 %
- Condition
- Annealed
Standards by form
| Plate, sheet & strip | ASTM B424 | |
|---|---|---|
| Pipe & tube | ASTM B423 | |
| Bar & rod | ASTM B425 | |
| Forgings | ASTM B564 |
Where it is specified
- Sulphuric and phosphoric acid service, pickling plant, sour gas
- Excellent resistance to chloride stress-corrosion cracking
- Titanium stabilisation resists sensitisation after welding
A 904L substitution reads almost right until you measure nickel
904L is cheaper, superficially similar and roughly half the nickel, which makes it the obvious substitution to attempt. The other failure is titanium below the 0.6 % floor, which removes the stabilisation that stops the alloy sensitising at the weld — a defect that only appears once the vessel is in service.
What we specify and check
- PMI reading Ni against the 38.0–46.0 window to rule out a 904L substitution
- Titanium verified against the 0.6 % minimum
- Molybdenum and copper confirmed against B424
- Stabilising anneal records where specified
We commission an accredited independent laboratory to test the heat before the material leaves China. You will receive that report unedited, whether it passes or not.
Request Incoloy 825
Tell us the form, dimensions and service conditions. We reply with availability, indicative landed price, lead time and the test regime we would specify for your application.
File an enquiry