316 Stainless vs 2205 Duplex Stainless
316 and 2205 both target chloride-rich, corrosive service, but they solve it differently. 316 is a classic austenitic grade with 2-3% molybdenum for pitting resistance, while 2205 is a duplex (roughly 50/50 austenite-ferrite) alloy with higher chromium and molybdenum. Engineers compare them when 316's strength or stress-corrosion resistance falls short and a tougher, higher-strength stainless is needed.
The verdict
Choose 316 for general marine, medical and chemical parts where its austenitic toughness, easy forming (40% elongation) and lower cost suffice. Choose 2205 when you need higher strength (450 MPa yield vs 316's 240 MPa), better pitting/crevice resistance and strong resistance to chloride stress-corrosion cracking — at higher cost and tougher machinability.
Side-by-side data
| Property | 316 Stainless | 2205 Duplex Stainless |
|---|---|---|
| Category | Stainless Steel | Stainless Steel |
| Density (g/cm³) | 8.0 | 7.8 |
| Tensile strength (MPa) | 515 | 655 |
| Yield strength (MPa) | 240 | 450 |
| Elongation (%) | 40 | 25 |
| Hardness | 217 HB | 31 HRC |
| Max service temp (°C) | 870 | 300 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 16 | 19 |
| Typically used for | Marine, medical & chemical environments | High-strength chloride-rich service |
Which should you choose?
Choose 316 Stainless when…
- You need a proven general-purpose corrosion-resistant grade for marine, medical or food service
- The part is deep-formed or welded — austenitic 316's 40% elongation forms easily
- Moderate strength is enough (240 MPa yield) and weight/section can carry the load
- Cost matters and duplex's premium isn't justified by the environment
- Cleanability and a familiar, widely-stocked grade are priorities
- Service temperature can run high (up to ~870°C) where duplex is limited to ~300°C
Choose 2205 Duplex Stainless when…
- You need roughly double the yield strength of 316 (450 vs 240 MPa) to reduce wall thickness/weight
- The environment is chloride-rich — seawater, brine, or process fluids that pit 316
- Chloride stress-corrosion cracking is a risk (duplex strongly resists it; austenitic 316 is vulnerable)
- You need higher crevice and pitting resistance from elevated Cr/Mo and nitrogen
- Pressure vessels or tanks where higher strength allows thinner, lighter sections
- Service stays below ~300°C (avoid duplex above that due to embrittlement)
Key differences that matter
- 2205 is duplex (~50/50 austenite-ferrite); 316 is fully austenitic — the microstructure drives strength and SCC behavior
- 2205 has far higher yield strength: 450 MPa vs 316's 240 MPa, allowing thinner sections
- 2205's higher Cr (~22%) and Mo (~3%) plus nitrogen give a higher PREN, so better pitting/crevice resistance than 316's 2-3% Mo
- 316 is much more vulnerable to chloride stress-corrosion cracking; duplex strongly resists it
- 316 forms and machines more easily; 2205 is harder (31 HRC) and tougher to machine
- 2205 costs more (higher relative cost) and is limited to ~300°C; 316 serves to ~870°C
- 316 is more ductile (40% vs 25% elongation) for severe forming
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Open the Material SelectorGet a Quote →Frequently asked questions
Is 2205 stronger than 316?
Yes, substantially. 2205's duplex structure gives roughly 450 MPa yield and 655 MPa tensile, against 316's 240 MPa yield and 515 MPa tensile — close to double the yield. That lets designers use thinner walls and lighter sections in tanks and piping, often offsetting 2205's higher per-kilo cost.
Which resists chloride corrosion better?
2205. Its higher chromium and molybdenum plus nitrogen give a higher pitting resistance number, so it withstands pitting and crevice attack better than 316's 2-3% Mo. Critically, duplex 2205 also resists chloride stress-corrosion cracking, a failure mode that austenitic 316 is notably susceptible to in hot chloride service.
Is 316 easier to machine than 2205?
Yes. 316 is a soft austenitic grade, while 2205 is harder (around 31 HRC) and its dual-phase structure work-hardens aggressively, demanding rigid setups, sharp tooling and slower feeds. Expect lower productivity and more tool wear on 2205, which is part of its higher finished-part cost.
Can both grades be welded?
Both are weldable. 316 welds with standard austenitic practice. 2205 needs more discipline — controlled heat input and proper filler to keep the austenite-ferrite phase balance; over- or under-cooling skews the balance and hurts corrosion resistance and toughness. With correct procedure, duplex welds perform very well.
When is 2205 worth the extra cost over 316?
When the chloride load is high enough to pit 316, when stress-corrosion cracking is a risk, or when 2205's higher strength lets you remove enough material to save weight and offset cost. For mild or general corrosion service below those thresholds, 316 is the more economical choice.
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.