S32205 Duplex Steel Plate S31803 Duplex Stainless Steel Material
Properties
1.4462 Sheet and Plate
Duplex stainless steels are extremely corrosion resistant, work
hardenable alloys. Their microstructures consist of a mixture of
austenite and ferrite phases. As a result, duplex stainless steels
display properties characteristic of both austenitic and ferritic
stainless steels. This combination of properties can mean some
compromise when compared with pure austenitic and pure ferritic
grades.
Duplex stainless steels are in most cases, tougher than ferritic
stainless steels. Strengths of duplex stainless steels can in some
cases be double that for austenitic stainless steels.
Whilst duplex stainless steels are considered resistant to stress
corrosion cracking, they are not as resistant to this form of
attack as ferritic stainless steels. However, the corrosion
resistance of the least resistant duplex stainless steels is
greater than that for the most commonly used grades of stainless
steels, i.e. 304 and 316.
Duplex steels are also magnetic, a property that can be used to
easily differentiate them from common austenitic grades of
stainless.
Property data given in this document is typical for flat rolled
products covered by EN 10088-2:2005. ASTM, EN or other standards
may cover products sold. It is reasonable to expect specifications
in these standards to be similar but not necessarily identical to
those given in this datasheet.
Chemical Composition
Spec: EN 10088-2:2005
1.4462 Steel
| Chemical Element | % Present |
|---|
| Carbon (C) | 0.0 - 0.03 |
| Chromium (Cr) | 21.00 - 23.00 |
| Manganese (Mn) | 0.0 - 2.00 |
| Silicon (Si) | 0.0 - 1.00 |
| Phosphorous (P) | 0.0 - 0.03 |
| Sulphur (S) | 0.0 - 0.02 |
| Nickel (Ni) | 4.50 - 6.50 |
| Nitrogen (N) | 0.10 - 0.22 |
| Molybdenum (Mo) | 2.50 - 3.50 |
| Iron (Fe) | Balance |
roperties
| Physical Property | Value |
|---|
| Density | 7.805 g/cm³ |
| Thermal Expansion | 13.7 x10^-6 /K |
| Modulus of Elasticity | 200 GPa |
| Thermal Conductivity | 19.0 W/m.K |
| Electrical Resistivity | 0.085 x10^-6 Ω .m |
Spec: EN 10088-2:2005
Sheet - Up to 8mm thick
| Mechanical Property | Value |
|---|
| Proof Stress | 500 Min MPa |
| Tensile Strength | 700 to 950 MPa |
| Elongation A50 mm | 20 Min % |
Spec: EN 10088-2:2005
Plate - over 8mm to 13.5mm Thick
| Mechanical Property | Value |
|---|
| Proof Stress | 460 Min MPa |
| Tensile Strength | 700 to 950 MPa |
| Elongation A50 mm | 25 Min % |
Spec: EN 10088-2:2005
Plate - Over 13.5mm to 75mm Thick
| Mechanical Property | Value |
|---|
| Proof Stress | 460 Min MPa |
| Tensile Strength | 640 to 840 MPa |
| Elongation A50 mm | 25 Min % |
Alloy Designations
Grade 1.4462/2205 is similar to but may not be a direct equivalent:
UNS S31803
UNS S32205
BS 318S13
Supplied Forms
- Fittings & Flanges
- Pipe
- Plate
- Sheet
- Tube
- Bar
Applications
Duplex stainless steels are typically used in:
~ Chemical processing, transport and storage
~ Oil and gas exploration and offshore rigs
~ Oil and gas refining
~ Marine environments
~ Pollution control equipment
~ Pulp & paper manufacturing
~ Chemical process plant
Corrosion Resistance
Duplex stainless steels are extremely corrosion resistant. They
have high resistance to intergranular corrosion. Even in chloride
and sulphide environments, duplex stainless steels exhibit very
high resistance to stress corrosion cracking.
The super duplex grades are even more resistant to corrosion.
Heat Resistance
The high chromium content of duplex stainless steels that protects
against corrosion, causes embrittlement at temperatures over about
300°C.
At low temperatures duplex stainless steels have better ductility
than the ferritic and martensitic grades. Duplex grades can readily
be used down to at least -50°C.
Fabrication
Fabrication of all stainless steels should be done only with tools
dedicated to stainless steel materials. Tooling and work surfaces
must be thoroughly cleaned before use. These precautions are
necessary to avoid cross contamination of stainless steel by easily
corroded metals that may discolour the surface of the fabricated
product.
Machinability
Although machinable, the high strengths of duplex stainless steels
makes machining difficult. As an example, machining of 2205 is
around 20% slower than for 304.
Machining can be enhanced by using the following rules:
~ Cutting edges must be kept sharp. Dull edges cause excess work
hardening.
~ Cuts should be light but deep enough to prevent work hardening by
riding on the surface of the material.
~ Chip breakers should be employed to assist in ensuring swarf
remains clear of the work
~ Low thermal conductivity of austenitic alloys results in heat
concentrating at the cutting edges. This means coolants and
lubricants are necessary and must be used in large quantities.
Heat Treatment
Duplex stainless steels cannot be hardened by heat treatment. They
can however be work hardened.
Solution treatment or annealing can be done by rapid cooling after
heating to around 1100°C.
Weldability
Duplex stainless steels have good weldability. All standard welding
processes can be used. They are not quite as easily welded as the
austenitic grades but low thermal expansion in duplex grades
reduces distortion and residual stresses after welding. The
recommended filler material for 2205 stainless steel is 2209.
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