ASTM A815 WP33
ASTM A815 WPS32550 Duplex Stainless Steel Pipe Fittings
ASTM A815 WPS32550 refers to duplex stainless steel pipe fittings manufactured under the ASTM A815 standard, which covers wrought ferritic, austenitic, and duplex (austenitic/ferritic) stainless steel fittings for pressure applications. Grade WPS32550 (UNS S32550, commonly known as Duplex 2550) offers a unique combination of high strength, excellent corrosion resistance, and superior mechanical properties.
These fittings are widely used in highly corrosive environments such as marine, offshore, chemical processing, and oil & gas industries, where both high strength and resistance to pitting and crevice corrosion are required.
Key Features
Excellent resistance to pitting, crevice, and stress corrosion cracking.
High mechanical strength and impact toughness.
Good weldability and formability.
Superior resistance to chloride-containing environments.
Excellent performance in acidic and alkaline media.
Enhanced durability under high pressure and high temperature conditions.
Specification
| Standard | ASTM A815 / ASME SA815 |
|---|---|
| Grade | WPS32550 |
| Material Type | Duplex Stainless Steel |
| UNS Number | S32550 |
| W.Nr. | 1.4507 |
| Form | Elbows, Tees, Reducers, Caps, Stub Ends, Crosses |
| Manufacturing Process | Seamless / Welded / Fabricated |
| Size Range | ½” NB to 48” NB |
| Schedule | SCH 10S to SCH 160 / XXS |
| Standard Ends | Beveled, Plain, Threaded, or Customized |
Equivalent Grades
| Standard | Grade |
|---|---|
| ASTM / ASME | UNS S32550 |
| EN | X2CrNiMoCuWN25-7-4 |
| W.Nr | 1.4507 |
| Trade Name | Ferralium 255, Duplex 2550 |
Available Sizes
Seamless Fittings: ½” to 24” NB
Welded Fittings: ½” to 48” NB
Thickness: SCH 10S, 40S, 80S, 160, XXS
Custom sizes available upon request
Chemical Composition
| Element | Content (%) |
|---|---|
| Chromium (Cr) | 24.0 – 27.0 |
| Nickel (Ni) | 4.5 – 6.5 |
| Molybdenum (Mo) | 2.9 – 3.9 |
| Copper (Cu) | 1.5 – 2.5 |
| Tungsten (W) | 0.5 – 1.0 |
| Nitrogen (N) | 0.10 – 0.25 |
| Manganese (Mn) | ≤ 1.5 |
| Silicon (Si) | ≤ 1.0 |
| Carbon (C) | ≤ 0.04 |
| Phosphorus (P) | ≤ 0.03 |
| Sulfur (S) | ≤ 0.02 |
| Iron (Fe) | Balance |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 750 MPa (min) |
| Yield Strength (0.2% Proof) | 550 MPa (min) |
| Elongation | 25% (min) |
| Hardness (Brinell) | ≤ 310 HB |
| Impact Toughness | Excellent (up to -46°C) |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.80 g/cm³ |
| Melting Point | 1370–1420°C |
| Modulus of Elasticity | 200 GPa |
| Thermal Conductivity | 14 W/m·K |
| Electrical Resistivity | 0.8 µΩ·m at 20°C |
Types of ASTM A815 WPS32550 Fittings
ASTM A815 WPS32550 Elbow
ASTM A815 WPS32550 Tee
ASTM A815 WPS32550 Reducers
ASTM A815 WPS32550 Caps
ASTM A815 WPS32550 Cross Fittings
ASTM A815 WPS32550 Nipples
ASTM A815 WPS32550 Coupling
ASTM A815 WPS32550 Stub Ends
Corrosion Resistance
ASTM A815 WPS32550 fittings offer outstanding resistance to:
Pitting & Crevice Corrosion in chloride environments.
Stress Corrosion Cracking in seawater and acidic conditions.
Sulphuric Acid and Phosphoric Acid exposure.
Oxidizing & Reducing Agents, maintaining structural integrity over time.
This makes them ideal for chemical processing, desalination plants, and marine systems.
Heat Resistance
Exhibits high strength and oxidation resistance up to ~300°C (572°F).
Suitable for continuous service in moderate temperature ranges.
Maintains excellent toughness and resistance to thermal fatigue.
Heat Treatment
Solution Annealing: 1120–1180°C followed by rapid water quenching.
Heat treatment helps restore duplex structure and corrosion resistance.
Not suitable for hardening by heat treatment.
Welding
Excellent weldability using GTAW (TIG), SMAW (Stick), or GMAW (MIG) methods.
Low heat input is recommended to preserve the duplex microstructure.
Post-weld solution annealing can enhance corrosion resistance.
Fabrication
Good formability and machinability with carbide tools.
Cold forming possible with moderate force.
Preheating not required before forming or welding.
Applications
Chemical Processing Plants
Oil & Gas Exploration
Marine & Offshore Engineering
Pulp and Paper Industry
Desalination Plants
Power Generation Systems
Heat Exchangers and Pressure Vessels