Overview
Duplex 2205 Stainless Steel (UNS S32205 / S31803) is the most widely used duplex stainless steel grade in the world. It features a dual-phase microstructure consisting of approximately 50% Austenite and 50% Ferrite, combining the advantages of both stainless steel families.
Duplex 2205 offers exceptional corrosion resistance, high mechanical strength, excellent chloride stress corrosion cracking resistance, and superior pitting resistance, making it a preferred material for offshore, marine, chemical processing, oil & gas, desalination, and pressure vessel applications.
Compared with SS316L, Duplex 2205 provides nearly twice the yield strength and significantly better resistance to chloride-induced corrosion.
Material Specification
| Property | Value |
|---|---|
| Material Designation | Duplex 2205 |
| Material Family | Duplex Stainless Steel |
| UNS Number | S32205 / S31803 |
| EN Grade | 1.4462 |
| Density | 7.80 g/cm³ |
| Magnetic Property | Slightly Magnetic |
| Standard Forms | Plate, Sheet, Coil, Pipe, Tube, Bar, Forgings |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Chromium (Cr) | 22.0–23.0 |
| Nickel (Ni) | 4.5–6.5 |
| Molybdenum (Mo) | 3.0–3.5 |
| Nitrogen (N) | 0.14–0.20 |
| Carbon (C) | ≤0.03 |
| Manganese (Mn) | ≤2.00 |
| Silicon (Si) | ≤1.00 |
| Phosphorus (P) | ≤0.030 |
| Sulfur (S) | ≤0.020 |
Mechanical Properties
Annealed Condition
| Property | Value |
|---|---|
| Tensile Strength | ≥620 MPa |
| Yield Strength | ≥450 MPa |
| Elongation | ≥25% |
| Hardness | ≤290 HB |
| Elastic Modulus | 200 GPa |
Strength Comparison
| Material | Yield Strength |
|---|---|
| Duplex 2205 | ≥450 MPa |
| SS316L | ≥170 MPa |
| SS304L | ≥170 MPa |
| SS321 | ≥205 MPa |
Duplex 2205 typically provides 2–2.5 times the yield strength of SS316L.
Physical Properties
| Property | Value |
|---|---|
| Density | 7.80 g/cm³ |
| Melting Point | 1350–1450°C |
| Thermal Conductivity | 19.0 W/m·K |
| Electrical Resistivity | 0.85 μΩ·m |
| Thermal Expansion Coefficient | 13.0 × 10⁻⁶/K |
| Specific Heat Capacity | 460 J/kg·K |
Corrosion Resistance
Corrosion Performance
| Environment | Performance |
|---|---|
| Marine Environment | Outstanding |
| Offshore Environment | Outstanding |
| Chloride Exposure | Outstanding |
| Salt Spray | Outstanding |
| Chemical Processing | Excellent |
| Acidic Solutions | Excellent |
| Industrial Atmosphere | Excellent |
PREN Value (Pitting Resistance Equivalent Number)
| Material | PREN |
|---|---|
| SS304 | 18–20 |
| SS316L | 24–26 |
| Duplex 2205 | 34–36 |
| Super Duplex 2507 | 40+ |
The higher PREN value indicates significantly improved resistance to pitting and crevice corrosion.
Stress Corrosion Cracking Resistance
One of Duplex 2205’s greatest advantages is its excellent resistance to:
- Chloride Stress Corrosion Cracking (SCC)
- Pitting Corrosion
- Crevice Corrosion
- Intergranular Corrosion
- Corrosion Fatigue
This makes it ideal for offshore and chemical processing applications.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM / AISI (USA) | Duplex 2205 |
| UNS | S32205 / S31803 |
| EN (Europe) | 1.4462 |
| DIN (Germany) | X2CrNiMoN22-5-3 |
| JIS (Japan) | SUS329J3L |
| GB/T (China) | 022Cr23Ni5Mo3N |
| ISO | X2CrNiMoN22-5-3 |
Available Forms
| Product Type | Availability |
|---|---|
| Stainless Plate | Yes |
| Stainless Sheet | Yes |
| Coil | Yes |
| Pipe | Yes |
| Tube | Yes |
| Round Bar | Yes |
| Forgings | Yes |
| Flanges | Yes |
Typical Applications
Oil & Gas Industry
- Offshore Platforms
- Subsea Equipment
- Flowlines
- Manifolds
- Pressure Vessels
Marine Industry
- Seawater Piping
- Shipbuilding Components
- Marine Fasteners
- Propulsion Systems
Chemical Processing Industry
- Reactors
- Storage Tanks
- Heat Exchangers
- Process Piping
Desalination Industry
- Reverse Osmosis Systems
- High Pressure Piping
- Seawater Intake Systems
Pulp & Paper Industry
- Digesters
- Bleaching Equipment
- Process Tanks
Power Generation
- Flue Gas Desulfurization Systems
- Heat Recovery Equipment
- Cooling Water Systems
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Turning | Good |
| CNC Milling | Good |
| Laser Cutting | Excellent |
| Waterjet Cutting | Excellent |
| Bending | Good |
| Forming | Good |
| TIG Welding | Excellent |
| MIG Welding | Excellent |
| Plasma Cutting | Excellent |
| Polishing | Good |
Advantages
Outstanding Corrosion Resistance
Superior to SS304 and SS316 in chloride environments.
High Mechanical Strength
Approximately twice the strength of austenitic stainless steels.
Excellent SCC Resistance
Ideal for offshore and marine service.
Weight Reduction Potential
Higher strength allows thinner wall designs.
Long Service Life
Reduces maintenance and replacement costs.
Cost Effective Alternative to Nickel Alloys
Provides excellent performance at lower cost than Inconel and Hastelloy.
Limitations
More Difficult to Machine
Higher strength increases machining complexity.
Welding Requires Process Control
Heat input must be carefully managed.
Not Suitable for Very High Temperatures
Generally recommended below 300°C continuous service.
More Expensive Than SS304
Higher alloy content increases material cost.
Comparison with Other Stainless Steels
| Property | Duplex 2205 | SS316L | SS304L | SS321 | Super Duplex 2507 |
|---|---|---|---|---|---|
| Yield Strength | Outstanding | Medium | Medium | Medium | Outstanding |
| Corrosion Resistance | Outstanding | Excellent | Good | Good | Exceptional |
| SCC Resistance | Outstanding | Moderate | Poor | Moderate | Exceptional |
| Marine Applications | Excellent | Good | Limited | Limited | Exceptional |
| Cost | High | Medium | Medium | Medium | Very High |
Comparison with Engineering Materials
| Material | Yield Strength (MPa) | Corrosion Resistance | Marine Use |
|---|---|---|---|
| Duplex 2205 | ≥450 | Outstanding | Excellent |
| SS316L | ≥170 | Excellent | Good |
| SS304L | ≥170 | Good | Limited |
| Super Duplex 2507 | ≥550 | Exceptional | Outstanding |
| Titanium Grade 2 | ≥275 | Outstanding | Outstanding |
| Inconel 625 | ≥460 | Exceptional | Outstanding |
Available Surface Finishes
Mill Finishes
- No.1 Finish
- 2B Finish
- Hot Rolled Finish
- Pickled Finish
Decorative Finishes
- Satin Finish
- Brushed Finish
- Mirror Polish
- Glass Bead Finish
Functional Finishes
- Passivation
- Electropolishing
- Shot Blasting
- Pickling
- Anti-Corrosion Surface Treatment
Frequently Asked Questions (FAQ)
What is Duplex 2205 stainless steel?
Duplex 2205 is a duplex stainless steel with a mixed austenitic-ferritic microstructure that provides exceptional strength and corrosion resistance.
What is Duplex 2205 used for?
Typical applications include:
- Offshore Platforms
- Chemical Processing Equipment
- Seawater Systems
- Desalination Plants
- Pressure Vessels
- Marine Structures
Is Duplex 2205 stronger than SS316L?
Yes.
| Property | Duplex 2205 | SS316L |
|---|---|---|
| Yield Strength | ≥450 MPa | ≥170 MPa |
| Tensile Strength | ≥620 MPa | ≥485 MPa |
Duplex 2205 is approximately twice as strong.
Is Duplex 2205 marine grade?
Yes. Duplex 2205 is considered one of the best materials for marine and offshore environments.
What is the difference between Duplex 2205 and SS316L?
| Property | Duplex 2205 | SS316L |
|---|---|---|
| Strength | Much Higher | Lower |
| SCC Resistance | Excellent | Moderate |
| Pitting Resistance | Better | Lower |
| Cost | Higher | Lower |
Is Duplex 2205 magnetic?
Yes. Duplex stainless steels are slightly magnetic because of their ferritic phase.
Can Duplex 2205 be welded?
Yes. Duplex 2205 has excellent weldability when proper welding procedures are followed.
Why is Duplex 2205 widely used offshore?
Because it combines:
- Exceptional Corrosion Resistance
- High Strength
- Excellent SCC Resistance
- Long Service Life
making it ideal for aggressive seawater environments.
Does GCNOV provide custom manufacturing services for Duplex 2205?
Yes. GCNOV provides:
- CNC Machining
- CNC Turning & Milling
- Precision Welding
- Pipe Fabrication
- Pressure Vessel Components
- Offshore Equipment Manufacturing
- Surface Finishing
- Prototype Development
- Low-Volume Production
- Mass Production