Designated as UNS N08020, Alloy 20 (also known as “Incoloy 020” or “Incoloy 20”) is a nickel-iron-chromium alloy with additions of copper and molybdenum. It has exceptional corrosion resistance to sulfuric acid, choloride stress-corrosion cracking, nitric acid, and phosphoric acid. Alloy 20 can be readily hot-formed or cold-formed to valves, pipe fittings, flanges, fasteners, pumps, tanks, as well as heat exchanger components. The hot forming temperature should be in the range of 1400-2150°F [760-1175°C]. Usually, the heat treatment of annealing should be conducted at the temperature range of 1800-1850°F [982-1010°C]. Alloy 20 is widely used for the production of gasoline, organic & inorganic chemicals, pharmaceutical processing, and food industry.
1. Chemical Composition Requirements
| The Chemical Composition of Alloy 20, % |
| Nickel |
32.0-38.0 |
| Chromiun |
19.0-21.0 |
| Copper |
3.0-4.0 |
| Molybdenum |
2.0-3.0 |
| Iron |
Balance |
| Carbon |
≤0.07 |
| Niobium+tantalum |
8*C-1.0 |
| Managanese |
≤2.00 |
| Phosphorus |
≤0.045 |
| Sulfur |
≤0.035 |
| Silicon |
≤1.00 |
2. Mechanical Properties of Alloy 20
ASTM B462 Alloy 20 (UNS N08020) forged fittings and forged flanges.
| Tensile Strength, min. |
Yield Strength, min. |
Elongation, min. |
Young’s Modulus |
| Mpa |
ksi |
Mpa |
ksi |
% |
103ksi |
Gpa |
| 620 |
90 |
300 |
45 |
40 |
28 |
193 |
3. Physical Properties of Alloy 20
| Density |
Specific Heat |
Electrical Resistivity |
Thermal Conductivity |
| g/cm3 |
J/kg.°C |
µΩ·m |
W/m.°C |
| 8.08 |
500 |
1.08 |
12.3 |
4. Product Forms and Standards
| Product Form |
Standard |
| Rod, bar and wire |
ASTM B473, B472, B462 |
| Plate, sheet and strip |
ASTM A240, A480, B463, B906 |
| Seamless pipe and tube |
ASTM B729, B829 |
| Welded pipe |
ASTM B464, B775 |
| Welded tube |
ASTM B468, B751 |
| Welded fittings |
ASTM B366 |
| Forged flanges and forged fittings |
ASTM B462, B472 |