Duplex 2205 Tube Sheet
A 50/50 austenite-ferrite microstructure gives 2205 roughly double the yield strength of standard 316L stainless plus meaningfully better resistance to chloride pitting and stress-corrosion cracking — the default upgrade path once seawater or brine service pushes stainless past its limit.
Chemical Composition
| Element | Min % | Max % |
|---|---|---|
| Chromium (Cr) | 22.0 | 23.0 |
| Nickel (Ni) | 4.5 | 6.5 |
| Molybdenum (Mo) | 3.0 | 3.5 |
| Nitrogen (N) | 0.14 | 0.20 |
| Carbon (C) | — | 0.030 |
Pitting Resistance Equivalent Number (PREN)
Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 620 MPa min |
| Yield Strength (0.2% offset) | 450 MPa min |
| Elongation | 25% min |
| Brinell Hardness | 293 HB max |
Equivalent Grades
| Standard | Designation |
|---|---|
| ASTM / UNS | S32205 |
| EN / DIN | 1.4462 |
| JIS | SUS329J3L |
Available Product Forms
Duplex 2205 is most commonly ordered as Floating Tube Sheets for high-ΔT seawater cooling service, and as Forged Tube Sheets where large diameter and directional strength are both required.
Applicable Standards
Governed by ASTM A240/A182 for the material and TEMA / ASME Section VIII for the mechanical design.
Applications
2205 is the standard chloride-service upgrade from stainless — desalination, offshore oil & gas, and marine cooling water systems where 316L's PREN is no longer adequate but full super duplex or titanium isn't yet justified by cost.
Advantages & Limitations
Advantages
- Roughly double the yield strength of 316L — thinner sections possible
- Strong resistance to chloride stress-corrosion cracking
- Good cost-to-performance step up from austenitic stainless
Limitations
- Work-hardens faster, requiring different machining parameters
- Practical service temperature limit around 300°C
- Higher cost than standard stainless family
FAQ
When chloride concentration, temperature, or both push the required PREN above roughly 40 — super duplex 2507 offers a PREN around 42, at a further cost premium. 2205 covers the large majority of seawater and brackish-water applications adequately.
Yes — duplex welding requires controlled heat input to maintain the correct austenite-ferrite balance in the weld and heat-affected zone. This is standard practice for qualified duplex welders but isn't interchangeable with standard austenitic stainless welding procedures.
Yes, mildly — the ferrite phase (roughly half the microstructure) is magnetic, unlike fully austenitic stainless grades. This is a normal characteristic of duplex steel and doesn't indicate a material defect.