Alloy 20 Pipe Fittings
Alloy 20 Pipe Fittings ( UNS N08020 ) Manufacturer & Supplier
Alloy 20 Pipe Fittings, also known as Carpenter 20 or UNS N08020, are engineered nickel-iron-chromium alloy fittings designed for superior resistance to sulfuric acid, chlorides, pitting, and stress corrosion cracking. Alloy 20 is commonly used in chemical, petrochemical, pharmaceutical, and food processing industries for handling highly corrosive environments.
These fittings provide excellent mechanical strength, thermal stability, and long service life even in the harshest conditions. Alloy 20 is stabilized with niobium to prevent sensitization during welding, ensuring superior performance.
Key Features
Excellent resistance to sulfuric acid (H₂SO₄) and chloride-induced corrosion
High resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC)
Niobium stabilization prevents intergranular corrosion
Good mechanical strength and weldability
Suitable for elevated temperatures and aggressive chemical environments
Ideal for acidic, alkaline, and mixed media applications
Long-lasting performance and reliability in corrosive service
Specification
| Standard | Details |
|---|---|
| Material | Alloy 20 / UNS N08020 / Carpenter 20 / 2.4660 |
| Standards | ASTM B366, ASME SB366 |
| Type | Seamless, Welded, Buttweld, Forged, Fabricated |
| Size Range | ½” to 48” |
| Dimensions | ASME B16.9, ASME B16.28, MSS-SP-43 |
| Schedule | SCH 5S to SCH XXS |
| Forms | Elbow, Tee, Reducer, Cap, Stub End, Cross |
| Manufacturing | Seamless / Welded / Fabricated |
| Testing | PMI, IGC Test, NDT, Hydro Test |
Equivalent Grades
| Alloy | UNS | WNR |
|---|---|---|
| Alloy 20 | N08020 | 2.4660 |
Available Sizes
Buttweld Fittings: ½” to 48”
Forged Fittings: ⅛” to 4”
Schedules: SCH 5S, 10S, 40, 80, 160, XXS
Custom sizes available upon request
Chemical Composition
| Element | % Composition |
|---|---|
| Nickel (Ni) | 32 – 38 |
| Chromium (Cr) | 19 – 21 |
| Iron (Fe) | Balance |
| Copper (Cu) | 3 – 4 |
| Molybdenum (Mo) | 2 – 3 |
| Carbon (C) | 0.07 max |
| Manganese (Mn) | 2 max |
| Silicon (Si) | 1 max |
| Sulfur (S) | 0.035 max |
| Phosphorus (P) | 0.045 max |
| Niobium (Nb) | Stabilized |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 551 MPa (min) |
| Yield Strength (0.2% offset) | 241 MPa (min) |
| Elongation | 30% (min) |
| Brinell Hardness | 217 HB (max) |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.08 g/cm³ |
| Melting Range | 1357 – 1430°C |
| Electrical Resistivity | 0.99 µΩ·m |
| Thermal Conductivity | 12 W/m·K |
| Modulus of Elasticity | 195 GPa |
Types of Alloy 20 Pipe Fittings
Buttweld Fittings
Alloy 20 Elbow (45°, 90°, 180°)
Alloy 20 Tee (Equal / Reducing)
Alloy 20 Concentric Reducer
Alloy 20 Eccentric Reducer
Alloy 20 Stub End (Short / Long)
Alloy 20 Pipe Cap
Alloy 20 Cross
Forged / Threaded Fittings
Couplings
Unions
Nipples
Plugs
Bushings
Corrosion Resistance
Alloy 20 provides outstanding resistance to:
Sulfuric acid (H₂SO₄) in all concentrations
Chloride-induced pitting and crevice corrosion
Stress corrosion cracking (SCC)
Nitric acid, phosphoric acid, and organic acids
Hot seawater and brine environments
Heat Resistance
Suitable for service up to 500°C
Maintains stability and strength at elevated temperatures
Resistant to carbide precipitation during welding
Good thermal fatigue resistance
Heat Treatment
Alloy 20 is typically annealed at 925–980°C followed by rapid cooling
Stabilization treatment avoids intergranular corrosion
Stress-relieving heat treatment applied after heavy fabrication
Welding
Excellent weldability using standard methods
GTAW (TIG)
GMAW (MIG)
SMAW (Stick)
Niobium stabilization prevents post-weld corrosion
Filler metals recommended: Alloy 20 (ERNiCrMo-3 or similar)
Avoid excessive heat input to minimize grain growth
Fabrication
Easy to machine, bend, and form
Can be hot-worked at 950–1200°C
Cold-working increases strength
Suitable for deep drawing and forming
Applications
Chemical Processing Plants
Sulfuric Acid & Phosphoric Acid Systems
Petrochemical Refineries
Food & Beverage Processing
Pharmaceutical Equipment
Power Generation
Marine & Offshore Systems
Pulp & Paper Industry
Pickling Equipment
Storage Tanks & Heat Exchangers