Incoloy 20 is a nickel-chromium alloy widely used in various industries due to its excellent corrosion resistance and high strength. It’s a popular choice for applications that require high resistance to acid attacks, sulfidation, and stress corrosion cracking. This blog post will closely examine the composition, physical and mechanical properties, uses, hardness, and heat treatment of Incoloy 20.
Incoloy 20 Composition
Incoloy 20 is a nickel-iron-chromium alloy with small amounts of molybdenum, copper, and niobium. Its chemical composition is as follows: Nickel 32-38%, Iron 39.5%, Chromium 19-21%, Copper 3-4%, Molybdenum 2-3%, and Niobium 0.1-0.3%. Adding copper and molybdenum enhances the alloy’s resistance to corrosion and improves its mechanical properties.
| Element | Content (%) |
|---|---|
| Nickel, Ni | 32-38 |
| Iron, Fe | 35 |
| Chromium, Cr | 19-21 |
| Copper, Cu | 3-4 |
| Molybdenum, Mo | 2-3 |
| Manganese, Mn | ≤2 |
| Niobium, Nb | ≤1 |
| Silicon, Si | ≤1 |
| Others | Remainder |
Incoloy 20 Physical Properties
Incoloy 20 has a density of 8.12 g/cm³, a melting point of 1443-1453°C, and a thermal conductivity of 14.9 W/m.K. Its electrical resistivity is 1.08 ×10^-6 Ωm at room temperature. Incoloy 20 is non-magnetic and has good thermal stability, making it suitable for high-temperature applications.
Incoloy 20 Mechanical Properties
Incoloy 20 has a high tensile strength of 620 MPa and a yield strength of 300 MPa. It also has good elongation and toughness, allowing it to withstand high-stress environments and extreme temperatures. Cold working and annealing processes enhance the alloy’s mechanical properties.
| Properties | Metric | Imperial |
|---|---|---|
| Tensile strength(annealed) | 620 MPa | 89.9 ksi |
| Yield strength(annealed) | 300 MPa | 43.5 ksi |
| Elongation at Break | 41% | 41% |
Incoloy 20 Equivalents
- UNS N08020
- ASME SB-462 – SB 464
- ASME SB 468
- ASTM B 462
- ASTM B 464
- ASTM B 472
- ASTM B 474
- ASTM B 751.
Incoloy 20 Specifications
| Pipe Smls | Pipe Welded | Tube Smls | Tube Welded | Sheet/Plate | Bar | Forging | Fitting |
|---|---|---|---|---|---|---|---|
|
B729
|
B464
|
B729
|
B468
|
B463
|
B473
|
B462
|
B366
|
Incoloy 20 Uses
Incoloy 20 is commonly used in chemical processing, petrochemical, and pharmaceutical industries, where it’s exposed to harsh environments. It’s used in equipment such as heat exchangers, reactors, pumps, valves, and other components that require corrosion-resistant properties. Incoloy 20 is also used to produce sulfuric acid, nitric acid, and phosphoric acid.
Incoloy 20 Hardness
Incoloy 20 has a 155-207 HB (Brinell hardness) and 15 Rockwell C hardness. Its hardness can be further improved by cold working or heat treatment.
Incoloy 20 Heat Treatment
Incoloy 20 can be annealed at 871-982°C for an extended period to improve its mechanical properties. It can also be solution heat treated at 1093-1204°C, followed by quick quenching in water or oil. This process improves the alloy’s hardness, strength, and resistance to corrosion.
Conclusion
Incoloy 20 is a versatile nickel-chromium alloy widely used in various industries requiring high corrosion resistance, high temperatures, and extreme stresses. Its unique properties make it an excellent choice for equipment and components that operate in challenging environments. With its high strength, good elongation, and excellent thermal stability, Incoloy 20 is undoubtedly a top-of-the-line alloy that can withstand the toughest conditions.
