Duplex Stainless Steel 2205 (UNS S31803 / S32205)
Duplex 2205 is the most widely used grade in the duplex stainless steel family. Its name comes from its unique microstructure, which consists of a roughly equal balance of Austenite and Ferrite. This "two-phase" design allows the material to inherit the best properties of both: the corrosion resistance of the 300-series and the high strength and chloride stress resistance of the 400-series.
At Aries Alloys, we supply Duplex 2205 as a high-performance upgrade to Type 316L. It is the premier choice for chemical processing and marine engineering where higher mechanical loads and aggressive chloride environments demand a more robust solution.
Key Performance Benefits
- Double the Strength: Provides a yield strength nearly twice that of standard austenitic stainless steels, allowing for thinner walls and significant weight savings in structural designs.
- SCC Immunity: Offers exceptional resistance to chloride-induced stress corrosion cracking (SCC), a common failure point for 304 and 316 grades.
- Superior Pitting & Crevice Resistance: With a high Chromium (22%) and Molybdenum (3%) content, it outperforms 316L in acidic and high-chloride process streams.
- High Energy Absorption: Excellent toughness and impact resistance, even in sub-zero temperatures.
- Lower Thermal Expansion: The ferritic component provides a lower coefficient of thermal expansion than austenitic steels, reducing warping in heat-transfer applications.
Technical Profile & Composition
The Chemistry of Balance:
The 2205 alloy is defined by its Nitrogen-enhanced chemistry. Nitrogen acts as a powerful austenite stabilizer and increases the material's pitting resistance. To ensure maximum corrosion performance, modern 2205 is usually "dual-certified" to meet the stricter S32205 standards, which require higher levels of Chromium, Molybdenum, and Nitrogen.
Mechanical & Physical Data:
- Density: 7.80 g/cm^3
- Yield Strength: ≥ 450 MPa (65,000 psi)
- Magnetic Property: Magnetic (due to the ferrite phase).
- Service Temperature: Recommended for use up to 600°F (316°C); prolonged exposure to higher temperatures can cause embrittlement.
Primary Industrial Use Cases
Aries Alloys is a strategic provider of Duplex 2205 for high-stress environments:
- Oil & Gas Exploration: Subsea flowlines, manifolds, and heat exchangers for sour gas and high-pressure wells.
- Chemical Processing: Pressure vessels, storage tanks, and piping for organic and inorganic acids.
- Desalination & Marine: High-pressure reverse osmosis systems, propellers, and shafts in seawater.
- Pulp & Paper: Digesters, bleach washers, and liquor tanks where chlorides are present.
- Construction: High-strength architectural fasteners and structural bridges in coastal regions.
Product Availability at Aries Alloys
We stock and supply Duplex 2205 in various forms complying with ASTM A240 and A276:
- Sheets & Plates: Precision-cut flat products for the fabrication of heavy-duty tanks and vessels.
- Round & Hex Bars: High-strength rods for machining corrosion-resistant fasteners and shafts.
- Seamless & Welded Pipes: High-integrity tubing for chemical transport and subsea applications.
- Forged Fittings: Flanges, elbows, and tees designed for high-pressure connectivity.