2.4660 / UNS N08020 / Nickel Alloy 20
Nickel Alloy 20 (UNS N08020 / 2.4660)
– The Superior Corrosion-Resistant Alloy for Harsh Chemical Environments
Nickel Alloy 20 (UNS N08020, W.Nr 2.4660) is an austenitic nickel-iron-chromium alloy specially designed to withstand sulfuric acid, phosphoric acid, and chloride-rich environments. Stabilized with niobium (Nb), it offers exceptional resistance to intergranular corrosion and stress corrosion cracking (SCC), making it ideal for chemical processing, food production, and pharmaceutical applications.
Key Features of Alloy 20
- Excellent sulfuric acid resistance (superior to 316L & 904L)
- Resists pitting & crevice corrosion in chlorides
- Stabilized with niobium to prevent sensitization
- Good mechanical strength up to 1000°F (537°C) per ASME
- Easily fabricated & welded
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron, Fe | 35 |
| Nickel, Ni | 32-38 |
| Chromium, Cr | 19-21 |
| Copper, Cu | 3-4 |
| Manganese, Mn | ≤2 |
| Molybdenum, Mo | 2-3 |
| Niobium, Nb | ≤1 |
| Silicon, Si | ≤1 |
| Carbon, C | ≤0.07 |
| Phosphorus, P | ≤0.045 |
| Sulfur, S | ≤0.035 |
Physical Properties
| Properties | Metric | Imperial |
|---|---|---|
| Density | 8.05 g/cm3 | 0.291 lb/in3 |
Mechanical Properties
| Properties | Metric | Imperial |
|---|---|---|
| Tensile strength (annealed) | 620 MPa | 89900 psi |
| Yield strength (annealed) | 300 MPa | 43500 psi |
| Elongation at break (annealed) | 41% | 41% |
Thermal Properties
| Properties | Metric | Imperial |
|---|---|---|
| Thermal expansion coefficient (@20-100°C/68-212°F) | 14.7 µm/m°C | 8.17 µin/in°F |
| Thermal conductivity | 12.3 W/mK | 85.4 BTU.in/hrft².°F |
Resistance to Corrosion
Alloy 20 has very good resistance to sulfuric acid. This alloy also shows suitable resistance in phosphoric acid, nitric acid, and aqueous salt solutions. Nickel Alloy 20 is an excellent option when chloride stress corrosion cracking is an issue, as it resists pitting and crevice corrosion. Caution should be taken in chloride ion-containing environments because the corrosion rate can increase significantly.
Fabrication and Heat Treatment
Alloy 20 can be formed by either hot-working or cold-working using traditional methods. Hot forged material should be heated between 2100°F and 2250°F with careful temperature control, ensuring that the material does not fall below 1800°F before forging. After hot working, anneal the material by heating to 1725°F and 1850°F for a minimum of 30 minutes per inch of thickness, followed by water quench.
When stress relieving is desired, heat to a temperature below 1000°F, followed by water quench after the desired time at temperature has been established. Annealing Alloy 20 should be between 1725°F and 1850°F for 30 minutes atthe temperature per inch of thickness. A lower hardness can be obtained by heating to 2100°F, but this may have a negative effect on the stabilization of the alloy.
Welding
Welding nickel alloy 20 is commonly performed via TIG, MIG, as well as submerged arc welding (SAW) using either the matching filler metal, ER320LR for TIG and MIG, and E320LR for SAW. When welding to dissimilar alloys such as 316 or higher alloys such as C276 and Alloy 22, AWS ERNiCrMo-3 can be used for TIG and MIG, while using ENiCrMo-3 for SAW.
Applications in Industry
1. Chemical Processing
- Sulfuric acid storage tanks & piping
- Phosphoric acid evaporators
- Agitators, heat exchangers, and reactor vessels
2. Food & Pharmaceutical
- Citric & acetic acid processing equipment
- Sanitary fittings & mixers
3. Oil & Gas
- Pump shafts, valve trim, and fasteners
- Offshore platform components
Why Choose Our Alloy 20 Products?
- Fully certified to ASTM B473 / ASME SB473
- Available in pipes, sheets, bars, and fittings
- Mill test reports (MTR) with full traceability
- Custom machining & fabrication services
Contact us today for a free quote & technical support!
WhatsApp:+86 19937075488
Email: susan@lorkgroup.com
Website: https://www.lorkalloy.com/products
Hot Tags: Alloy 20, Nickel Alloy 20, UNS N08020, W.Nr. 2.4660, 2.4660, Carpenter 20, 20Cb-3, Incoloy 20, NS143, NS1403, Ni-Fe-Cr alloy, niobium-stabilized, sulfuric acid resistant alloy, corrosion resistant alloy, chemical processing alloy
You Might Also Like
Send Inquiry