Nickel alloy 825 (Incoloy) (UNS N08825)
Nickel alloy 825 (Incoloy) (UNS N08825) — Resists sulphuric and phosphoric acids.
| UNS number | N08825 |
| Material family | Nickel-iron-chromium |
| Product specifications | B564, B366, B423 |
| Density (typical) | 8.14 g/cm³ (8140 kg/m³) |
| Weight of 6" Sch 40 pipe | 29.30 kg/m |
Specifications by product form
One alloy is ordered under different ASTM/ASME numbers depending on form: forged flanges and fittings, wrought buttweld fittings, and pipe or tube. For Nickel alloy 825 (Incoloy) the usual specifications are B564, B366, B423. Quote both the specification and the UNS number on purchase orders to avoid ambiguity.
Chemical and mechanical limits differ between these specifications — always check the edition of the standard named on your order and the mill test certificate.
Chemical composition & mechanical properties
| Property | Alloy 825 (Incoloy) |
|---|---|
| Family | Nickel-iron-chromium |
| UNS | N08825 |
| EN / W.Nr | 2.4858 NiCr21Mo |
| Basis spec | ASTM B564 |
| Density g/cm³ | 8.14 |
| Chemical composition, % | |
| C | 0.05 |
| Mn | 1.0 |
| S | 0.03 |
| Si | 0.5 |
| Cr | 19.5–23.5 |
| Ni | 38.0–46.0 |
| Mo | 2.5–3.5 |
| Cu | 1.5–3.0 |
| Ti | 0.6–1.2 |
| Fe | 22.0 min |
| Al | 0.2 |
| Mechanical properties (min) | |
| Tensile strength | 586 MPa (85 ksi) |
| Yield strength (0.2%) | 241 MPa (35 ksi) |
| Elongation | 30% |
| Hardness (max) | – |
| PREN (min, from spec) | 27.8 |
Single values are maximums; ranges are min–max; "bal" = balance. Limits are typical of the basis specification for that product form — forgings, pipe and fittings specifications differ slightly. Always check the exact specification, edition and the mill test certificate.
Frequently asked questions
What is the UNS number of Nickel alloy 825 (Incoloy)?
N08825.
Which ASTM specifications cover Nickel alloy 825 (Incoloy)?
B564, B366, B423.
What is the density of Nickel alloy 825 (Incoloy)?
About 8.14 g/cm³ (8140 kg/m³), used for weight calculations.
Last updated 2026-11-02