20
Wst. 2.4660
UNS N08020
Stock program: Available on request
Specification:
ASTM B 729/ASME SB 729
ASTM B 468/ASME SB 468
NACE MR0175
Seamless and welded condition
Maximum service temperature: 500°C / 930°F
Alloy 20 is an austenitic, nickel-iron-chromium based super alloy with additions of copper and molybdenum which provide maximum resistance to acid attack and specifically sulfuric acid. The alloy 20 has excellent resistance to general corrosion, pitting and crevice corrosion in hostile environments. The alloy 20 is stabilized with niobium against sensitization and resultant inter granular corrosion. Alloy 20 appears to fall between both the stainless steel and nickel alloy categories as it contains characteristics of both.
Characteristics:
- Superior resistance to stress-corrosion cracking in boiling 20 to 40% sulfuric acid
- Excellent general corrosion resistance to sulfuric acid
- Good mechanical properties and fabric ability
- Minimal carbide precipitations during welding
- Very good resistance to chloride stress-corrosion cracking
Market applications:
- Chemical processing industry
- Pharmaceutical and food plants
- Petrochemical process equipment
- Acid cleaning and pickling equipment
- Heat exchanges
Technical details
| Technical composition (%) | Fe | Cr | Ni | Mo | Mn | Si | P | C | S | Nb | Cn | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 20 | min | Bal. | 19.0 | 32.0 | 2.0 | – | – | – | – | – | – | 3.0 | |||||||||||
| max | – | 21.0 | 38.0 | 3.0 | 2.00 | 1.00 | 0.045 | 0.070 | 0.035 | 8xC (1.0 max) | 4.0 | ||||||||||||
| Mechanical properties | 20 | |
|---|---|---|
| Tensile strenght (mpa, min) nl | 551 | |
| Yield strength (0.2% offset mpa, min) | 241 | |
| Elongation (%, min) | 30 | |
| Density / weight (g / cm3 / kg) | 8.1 |