UNS S31803 / 2205 Duplex Stainless Steel

UNS S31803 Duplex Stainless Steel | Nifty Alloys

Nifty Alloys supplies high-quality UNS S31803 Duplex Stainless Steel that meets international standards of strength, corrosion resistance, and toughness. Also referred to as Duplex 2205, the stainless steel possesses the best traits of ferritic and austenitic stainless steels and is therefore the material of choice for challenging industries such as oil & gas, chemical processing, marine, and power generation.

If you are looking for quality UNS S31803 stainless steel plates, sheets, bars, or pipes, Nifty Alloys is your trusted global supplier.

What is UNS S31803 Duplex Stainless Steel?

UNS S31803 is a duplex stainless steel that is designed with a two-phase microstructure of almost equal amounts of austenite and ferrite. This kind of structure gives it:

• Double strength (twice as strong as 316 stainless steel).
• Good corrosion resistance, especially against pitting and crevice corrosion.
• Improved resistance to chloride stress corrosion cracking.
• Very good weldability and formability for industrial purposes.

UNS S31803 is also available by the trade name Duplex 2205, although there are minor differences in composition. It remains one of the most highly demanded duplex grades for aggressive engineering and marine applications.

Key Properties of UNS S31803 Duplex Stainless Steel

Mechanical Properties:

• High yield strength (varies from around 450 MPa).
• Very good tensile strength (varies from around 620 MPa).
• Good toughness and elongation.

Physical Properties:

• Density: 7.8 g/cm³
• Modulus of Elasticity: 200 GPa
• Melting Point: 1,460 °C
• Magnetic: Yes (due to ferritic phase)

Corrosion Resistance:

• Excellent pitting, crevice corrosion, and general corrosion resistance.
• Improved performance over 316L and 317L in chloride environments.
• Good performance in seawater, chemical plants, and offshore platforms.

Duplex 2205 vs Super Duplex Stainless Steel

• Duplex 2205 (UNS S31803 / S32205) provides excellent strength and corrosion resistance for most industrial applications.
• Super Duplex Stainless Steel (like Super Duplex Stainless Steel) offers higher corrosion resistance and mechanical strength, making it ideal for extremely harsh conditions.

Forms We Supply at Nifty Alloys

We stock and supply UNS S31803 in multiple product forms to meet customer needs:

• Duplex Stainless Steel Round Bars
• Duplex Stainless Steel Plates & Sheets
• Duplex Stainless Steel Pipes & Tubes
• Duplex Stainless Steel Flanges & Fittings
• Custom-cut profiles and forgings

All products are tested, certified, and supplied with complete documentation for traceability.