316L vs Duplex 2205
When 316L isn't enough — but nickel alloys would be overkill. Duplex 2205 fills the gap with double the strength and superior chloride resistance.
| Property | 316L | Duplex 2205 |
|---|---|---|
| UNS | S31603 | S32205 |
| Microstructure | 100% austenite | ~50/50 austenite-ferrite |
| Tensile Strength | ≥ 485 MPa | ≥ 655 MPa (+35%) |
| Yield Strength | ≥ 170 MPa | ≥ 450 MPa (+165%) |
| Elongation | ≥ 40% | ≥ 25% |
| PREN | 24 – 28 | 34 – 38 |
| Critical Pitting Temp | 15 – 25°C | 40 – 50°C |
| Cl-SCC Resistance | Susceptible above 80°C | Immune up to 120°C |
| Max Service Temp | 800°C | 300°C (475°C embrittlement) |
| Density | 8.00 g/cm³ | 7.85 g/cm³ |
| Relative Cost | 1.0× (base) | 2.0 – 2.5× material / 1.2-1.5× project |
| Wall Thickness Saving | — | 30 – 40% vs 316L at equal pressure |
| NACE MR0175 | ≤ HRC 22, temp ≤ 60°C | ≤ HRC 28, temp ≤ 232°C |
450 MPa
2205 Yield (2.6× 316L)
PREN 35
Seawater Service Grade
1.2-1.5×
Project Cost vs 316L
The Bottom Line
Duplex 2205's 2.6× yield strength means 30-40% thinner walls at the same pressure rating. The material costs 2× more, but the project cost premium is only 20-50% after accounting for less material, lighter structures, and reduced welding. For offshore, desalination, and any chloride environment above 1,000 ppm at elevated temperature — 2205 is the cost-optimal solution between 316L and nickel alloys.