Nickel alloys / UNS N08020
Alloy 20 is a niobium-stabilised nickel-iron-chromium alloy with copper and molybdenum, developed for sulphuric acid service and resistant to chloride stress-corrosion cracking.
- UNS N08020
- W.Nr. 2.4660
- Spec ASTM B463
- Density 8.08 g/cm³
Also known as / equivalents
| System | Designation |
|---|---|
| UNS | N08020 |
| W.Nr. | 2.4660 |
| EN | NiCr20CuMo |
| Also known as | Carpenter 20, 20Cb-3, 2.4660 |
Chemical composition
| Element | Min % | Max % |
|---|---|---|
| Ni | 32.0 | 38.0 |
| Cr | 19.0 | 21.0 |
| Mo | 2.0 | 3.0 |
| Cu | 3.0 | 4.0 |
| Nb+Ta | 8×C | 1.00 |
| C | — | 0.07 |
| Mn | — | 2.00 |
| P | — | 0.045 |
| S | — | 0.035 |
| Si | — | 1.00 |
| Fe | Bal. | — |
Mechanical properties
| Property | Value |
|---|---|
| Tensile strength (min) | 551 MPa (79.9 ksi) |
| Yield strength, 0.2% offset (min) | 241 MPa (35.0 ksi) |
| Elongation in 50 mm (min) | 30 % |
Physical properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.08 g/cm³ | 0.292 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
Alloy 20: Acid pickling, chemical, pharmaceutical. Chemical and petrochemical plant, sour-gas and oilfield equipment, furnace and heat-treatment hardware, power generation, marine engineering and aerospace components.
Alloy 20 vs Incoloy® 825
| Alloy 20 | Incoloy® 825 | |
|---|---|---|
| UNS | N08020 | N08825 |
| Key property | Sulphuric-acid grade | Acid & sour-gas resistant |
| Typical use | Acid pickling, chemical, pharmaceutical | Sulphuric acid, oil & gas tubing, pickling |
| Cr (wt %) | 19.0–21.0 | 19.5–23.5 |
| Ni (wt %) | 32.0–38.0 | 38.0–46.0 |
| Mo (wt %) | 2.0–3.0 | 2.5–3.5 |
| C (wt %) | ≤ 0.07 | ≤ 0.05 |
| Tensile / yield (min, MPa) | 551 / 241 | 586 / 241 |
Frequently asked questions
What is the UNS number of Alloy 20?
Alloy 20 is designated UNS N08020 (W.Nr. 2.4660, EN NiCr20CuMo).
What is Alloy 20 used for?
Sulphuric-acid grade. Typical uses: acid pickling, chemical, pharmaceutical.
Is Alloy 20 magnetic?
Non-magnetic.
In which forms can I buy Alloy 20 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 Alloy 20?
Yes. Actual values are given in the Mill Test Certificate (EN 10204 3.1) supplied with each order.
What is the difference between Alloy 20 and Incoloy® 825?
Alloy 20: sulphuric-acid grade. Incoloy® 825: acid & sour-gas 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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