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Should I replace SS 316L with duplex 2205?
Short answer
Replace SS 316L with duplex 2205 when chloride stress-corrosion cracking, pitting or high design pressure is the problem: 2205 has about 2.6 times the yield strength, a PREN of about 35 against 24 and far better SCC resistance. Keep SS 316L for hygienic, cryogenic and high-temperature service, where duplex is limited.
SS 316L vs Duplex 2205 at a glance
| Property | SS 316L | Duplex 2205 |
|---|---|---|
| UNS | S31603 | S32205 / S31803 |
| EN | 1.4404 | 1.4462 |
| Family | Austenitic stainless steel | Duplex stainless steel |
| C (%) | 0.030 max | 0.030 max |
| Cr (%) | 16.0 – 18.0 | 22.0 – 23.0 |
| Ni (%) | 10.0 – 14.0 | 4.5 – 6.5 |
| Mo (%) | 2.00 – 3.00 | 3.0 – 3.5 |
| N (%) | 0.10 max | 0.14 – 0.20 |
| Tensile strength | 485 MPa (70 ksi) | 655 MPa (95 ksi) |
| Yield strength | 170 MPa (25 ksi) | 450 MPa (65 ksi) |
| PREN | 23 – 25 | 34 – 35 |
| Density | 8 g/cm³ | 7.8 g/cm³ |
| Magnetic | Essentially non-magnetic when annealed; cold work can make it slightly magnetic. | Magnetic, because of its ferrite content. |
| Typical use | Chemical and fertiliser process piping | Oil and gas flowlines, manifolds and process piping |
Which should you choose?
There's no universal "winner": the right choice depends on service conditions, codes and cost. Share your conditions with us for a recommendation.
A cost check that often surprises buyers
Where 2205 is not the answer
Duplex loses toughness after long exposure above about 300 °C and at very low temperatures, so it is not used for cryogenic or hot service. It also needs qualified welding procedures with ferrite control.
Products in both grades
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Frequently asked questions
Is duplex 2205 magnetic?
Yes. Its ferritic phase makes it magnetic, unlike SS 316L.
Can 2205 be used in food processing?
Yes, it is used for tanks and piping where chlorides would crack SS 316L, provided surface finish and cleaning requirements are met.
What is the main difference between SS 316L and Duplex 2205?
2205 has about 2.6× the yield strength of SS 316L, a higher PREN (≈35 against ≈24) and far better chloride SCC resistance. SS 316L is easier to fabricate and suits cryogenic to high temperatures, while 2205 is limited to about 300 °C.
When should I choose SS 316L?
Hygienic, cryogenic and moderate-chloride service.
When should I choose Duplex 2205?
Chloride SCC risk, strength-driven designs, brackish water.
Can SS 316L replace Duplex 2205?
Only when the design, code and specification allow it. Strength, corrosion resistance and temperature limits differ, so substitution must be approved by the design authority.
Which has better pitting resistance, SS 316L or Duplex 2205?
Typical PREN: SS 316L 23 – 25, Duplex 2205 34 – 35. A higher PREN generally means better chloride pitting resistance.