Nickel alloys / UNS N08825
Incoloy® 825 is a nickel-iron-chromium alloy with molybdenum and copper, resisting sulphuric and phosphoric acids, chloride stress-corrosion cracking and sour oil-and-gas environments.
- UNS N08825
- W.Nr. 2.4858
- Spec ASTM B424
- Density 8.14 g/cm³
Also known as / equivalents
| System | Designation |
|---|---|
| UNS | N08825 |
| W.Nr. | 2.4858 |
| EN | NiCr21Mo |
| Also known as | Alloy 825, 2.4858, NiCr21Mo |
Chemical composition
| Element | Min % | Max % |
|---|---|---|
| Ni | 38.0 | 46.0 |
| Fe | 22.0 | — |
| Cr | 19.5 | 23.5 |
| Mo | 2.5 | 3.5 |
| Cu | 1.5 | 3.0 |
| Ti | 0.6 | 1.2 |
| C | — | 0.05 |
| Mn | — | 1.0 |
| S | — | 0.03 |
| Si | — | 0.5 |
| Al | — | 0.2 |
Mechanical properties
| Property | Value |
|---|---|
| Tensile strength (min) | 586 MPa (85.0 ksi) |
| Yield strength, 0.2% offset (min) | 241 MPa (35.0 ksi) |
| Elongation in 50 mm (min) | 30 % |
Physical properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.14 g/cm³ | 0.294 lb/in³ |
| Magnetic response | Non-magnetic | — |
Available forms & specifications
| Form | Specification | Size range |
|---|---|---|
| Sheets & plates | ASTM B168, B443, B409, B424, B127, B162 | 0.3 mm – 6 mm |
| Seamless pipe & tube | ASTM B167, B444, B407, B423, B165, B161 | 1/8" – 24" NB |
| Bars & rods | ASTM B166, B446, B408, B425, B164, B160 | 3 mm – 500 mm |
| Flanges & forgings | ASTM B564 | 1/2" – 48" NB (larger on request) |
| Buttweld fittings | ASTM B366 | 1/2" – 48" NB |
Corrosion & temperature resistance
Nickel-based alloys resist caustic alkalis, chloride stress-corrosion cracking and many acids, and keep their strength and oxidation resistance at temperatures where stainless steels fail.
Applications
Incoloy® 825: Sulphuric acid, oil & gas tubing, pickling. Chemical and petrochemical plant, sour-gas and oilfield equipment, furnace and heat-treatment hardware, power generation, marine engineering and aerospace components.
Incoloy® 825 vs Inconel® 625
| Incoloy® 825 | Inconel® 625 | |
|---|---|---|
| UNS | N08825 | N06625 |
| Key property | Acid & sour-gas resistant | Strong, highly corrosion resistant |
| Typical use | Sulphuric acid, oil & gas tubing, pickling | Offshore, chemical, aerospace, flue-gas systems |
| Cr (wt %) | 19.5–23.5 | 20.0–23.0 |
| Ni (wt %) | 38.0–46.0 | 58.0 |
| Mo (wt %) | 2.5–3.5 | 8.0–10.0 |
| C (wt %) | ≤ 0.05 | ≤ 0.10 |
| Tensile / yield (min, MPa) | 586 / 241 | 758 / 379 |
Frequently asked questions
What is the UNS number of Incoloy® 825?
Incoloy® 825 is designated UNS N08825 (W.Nr. 2.4858, EN NiCr21Mo).
What is Incoloy® 825 used for?
Acid & sour-gas resistant. Typical uses: sulphuric acid, oil & gas tubing, pickling.
Is Incoloy® 825 magnetic?
Non-magnetic.
In which forms can I buy Incoloy® 825 from Rajkamal Metals?
Coils & Strips, Sheets & Plates, Pipes & Tubes, Round Bars & Rods, Flanges, Buttweld Fittings, Socket Weld & Threaded Fittings, Fasteners, Ferrule / Instrumentation Fittings, Dish Ends, Custom Orders. Sizes as per standard; other sizes on request.
Do you supply a Mill Test Certificate with Incoloy® 825?
Yes. Actual values are given in the Mill Test Certificate (EN 10204 3.1) supplied with each order.
What is the difference between Incoloy® 825 and Inconel® 625?
Incoloy® 825: acid & sour-gas resistant. Inconel® 625: strong, highly corrosion resistant. See the comparison table on this page.
Last updated: 30 October 2026. Grade names identify the supply range; designations are not engineering equivalents. Availability, make, origin and documentation are confirmed at quotation.
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