ALLOY 20
Alloy 20 (UNS N08020) is an austenitic, nickel-iron-chromium based super alloy with additions of Copper and Molybdenum which provide resistance to hostile environments, pitting, and crevice corrosion. It is also stabilized with Columbium to minimize carbide precipitation during welding. Alloy 20 appears to fall between both the stainless and nickel categories as it contains characteristics of both. It was designed for maximum resistance to acid attack and demonstrates superior resistance to stress-corrosion cracking in boiling 20% to 40% sulfuric acid, and also has excellent general corrosion resistance to sulfuric acid and to chloride stress corrosion cracking.
Alloy 20 has good mechanical properties at both ambient and elevated temperatures, up to approximately 930°F (500°C) and is readily fabricated by usual industrial processes.
ALLOY 20 WAS ORIGINALLY DESIGNED FOR USE IN SULFURIC ACID RELATED APPLICATIONS; HOWEVER, IT IS NOW FREQUENTLY USED IN A WIDE VARIETY OF INDUSTRIES. APPLICATIONS THAT COMMONLY USE ALLOY 20 INCLUDE:
- Chemical and allied industries
- Food and dye production
- Heat exchangers
- Explosives
- Tanks
- Valves
- Pickling racks
- Manufacture of synthetic rubber and plastics
- Pharmaceuticals
- SO2 scrubbers and other severe environments
ALLOY 20 SHEETS
ALLOY 20 ROUND BARS CHEMICAL COMPOSITION
| Element | Alloy 20 |
| Ni | 32 – 38 |
| Fe | Bal |
| C | 0.02 max |
| Mn | 1 – 2 |
| Si | 0.7 max |
| Cu | 3 – 4 |
| Cr | 19 – 21 |
| Mo | 2 – 3 |
| S | 0.005 max |
| P | 0.02 max |
| Nb | 0.1 – 0.3 |
IN WHAT APPLICATIONS IS ALLOY 20 USED?
- Synthetic rubber manufacturing equipment
- Processing of pharmaceuticals, plastics and organic and heavy chemicals
- Tanks, piping, heat exchangers, pumps, valves, and other process equipment
- Acid cleaning and pickling equipment
- Chemical process piping, reactor vessels
- Bubble caps
- Petrochemical process equipment
- Food and dye production
ALLOY 20 ROUND BARS PHYSICAL & MECHANICAL PROPERTIES
| Element | Alloy 20 |
| Density | 8.1 g/cm3 |
| Melting Point | 1443 °C (2430 °F) |
| Tensile Strength | Psi -80,000, MPa -551 |
| Yield Strength (0.2%Offset) | Psi – 35,000, MPa – 241 |
| Elongation | 30 % |