ASTM A240 UNS S31803 / S32205 Duplex Stainless Steel Plate – EN 1.4462
ASTM A240 UNS S31803 / S32205 Duplex Stainless Steel Plate, commonly known as Duplex 2205 Plate, combines high mechanical strength with good resistance to pitting, crevice corrosion and chloride stress corrosion cracking.
UNS S31803 and S32205 are widely used for pressure vessels, chemical processing equipment, offshore structures, oil & gas systems, pulp and paper equipment and other corrosive industrial applications.
The commonly cross-referenced European designation is EN 1.4462 / X2CrNiMoN22-5-3.
ASTM A240 UNS S31803 Specification
| Item | Specification |
|---|---|
| Product | Duplex Stainless Steel Plate / Sheet |
| ASTM Standard | ASTM A240/A240M |
| UNS Grades | S31803 / S32205 |
| Common Name | Duplex 2205 |
| EN Designation | 1.4462 / X2CrNiMoN22-5-3 |
| Delivery Condition | Solution Annealed |
| Product Form | Hot Rolled Plate / Cold Rolled Sheet, as specified |
| Surface | No.1 / 2D / 2B or project-specific finish, as applicable |
| Dimensions | According to RFQ and available mill range |
| General Tolerances | ASTM A480/A480M where applicable |
| Certification | EN 10204 3.1 when specified |
| Optional Testing | PMI, Ferrite, ASTM A923, ASTM G48, NDT or TPI when specified |
What Is Duplex 2205 Stainless Steel Plate?
Duplex 2205 is an austenitic-ferritic stainless steel containing approximately 22% chromium, 5% nickel and 3% molybdenum with controlled nitrogen.
Its duplex microstructure provides significantly higher yield strength than conventional 300-series austenitic stainless steels while maintaining good corrosion resistance and weldability.
Duplex 2205 is particularly useful where resistance to chloride stress corrosion cracking, pitting and crevice corrosion is important.
UNS S31803 vs S32205 vs EN 1.4462
S31803 and S32205 belong to the same Duplex 2205 material family, but they should not simply be treated as identical UNS grades.
| Grade | Standard System | Relationship |
|---|---|---|
| UNS S31803 | UNS / ASTM | Original Duplex 2205 designation |
| UNS S32205 | UNS / ASTM | 2205 grade with tighter Cr, Mo and N chemistry limits |
| 1.4462 / X2CrNiMoN22-5-3 | EN | Common European designation for Duplex 2205 |
S32205 was developed with tighter minimum chromium, molybdenum and nitrogen levels to provide more consistent corrosion performance.
Many modern commercial Duplex 2205 products can meet both S31803 and S32205 chemistry requirements and may be supplied with dual certification.
However, the exact grade and certification should always be confirmed from the Material Test Certificate (MTC).
EN 1.4462 is commonly cross-referenced with S31803/S32205, but cross-standard substitution should be confirmed against the applicable product standard and project specification.
Chemical Composition
| Element | UNS S31803 | UNS S32205 |
|---|---|---|
| C | ≤ 0.030% | ≤ 0.030% |
| Mn | ≤ 2.00% | ≤ 2.00% |
| Si | ≤ 1.00% | ≤ 1.00% |
| P | ≤ 0.030% | ≤ 0.030% |
| S | ≤ 0.020% | ≤ 0.020% |
| Cr | 21.0–23.0% | 22.0–23.0% |
| Ni | 4.5–6.5% | 4.5–6.5% |
| Mo | 2.5–3.5% | 3.0–3.5% |
| N | 0.08–0.20% | 0.14–0.20% |
The tighter Cr, Mo and N ranges are the main chemistry difference between S31803 and S32205.
Actual chemical composition should be verified against the MTC for the supplied heat.
Mechanical Properties
Typical minimum room-temperature mechanical requirements for ASTM A240 Duplex 2205 plate are:
| Property | S31803 | S32205 |
|---|---|---|
| Yield Strength | 450 MPa min. | 450 MPa min. |
| Tensile Strength | 620 MPa min. | 655 MPa min. |
| Elongation | 25% min. | 25% min. |
| Hardness | 293 HB / 31 HRC max. | 293 HB / 31 HRC max. |
The high yield strength of Duplex 2205 can provide design advantages compared with conventional austenitic stainless steels such as 304L and 316L.
ASTM A240 and ASTM A480
ASTM A240 / A240M specifies material requirements for stainless steel plate, sheet and strip used for pressure vessels and general applications.
ASTM A480/A480M provides general requirements for flat-rolled stainless products, including requirements related to dimensions, tolerances, finish and other general manufacturing conditions where applicable.
For plate procurement, dimensional tolerances should therefore be confirmed against the applicable ASTM A480/A480M requirements, ordered dimensions and product form.
Large tolerance tables should not be applied without confirming whether the material is quarto plate, coil-derived plate, sheet or another product form.
Testing and Inspection
Standard material compliance and additional project testing should be clearly distinguished.
Material supply normally includes verification of chemistry, mechanical properties, dimensions, surface condition and traceability according to the applicable material specification.
Project-specific requirements may additionally include PMI, ferrite measurement, hardness testing, ultrasonic testing, ASTM A923 testing, ASTM G48 corrosion testing, EN 10204 3.1/3.2 certification or third-party inspection.
ASTM A923 is specifically used to detect detrimental intermetallic phases in applicable duplex stainless steels.
These additional tests should be specified in the RFQ and should not automatically be treated as mandatory ASTM A240 requirements.
Applications
ASTM A240 S31803 / S32205 Duplex 2205 Plate is commonly used for pressure vessels, chemical process tanks, heat exchangers, offshore equipment, oil & gas facilities, pulp and paper equipment, desalination systems, marine equipment and structural components exposed to corrosive environments.
Suitability for a particular chloride, seawater, sour-service or chemical environment should be evaluated against the actual design temperature and service conditions.
How to Order Duplex 2205 Plate
A complete RFQ should include:
Grade + Standard + Thickness + Width + Length + Quantity/Weight + Surface + Certification + Additional Testing
Example:
PLATE, ASTM A240 UNS S32205, 10 × 2000 × 6000 MM, HOT ROLLED NO.1, SOLUTION ANNEALED, EN 10204 3.1, PMI 100%, QTY: 5 PCS
If dual certification is required, specify:
ASTM A240 UNS S31803 / S32205 DUAL CERTIFIED
Frequently Asked Questions
What is the difference between S31803 and S32205?
Both are Duplex 2205 grades. S32205 has tighter minimum Cr, Mo and N chemistry requirements, while S31803 has broader composition ranges.
Is UNS S31803 the same as S32205?
Not exactly. They belong to the same Duplex 2205 family, and many modern heats can meet both specifications, but the actual certification must be confirmed from the MTC.
Is EN 1.4462 equivalent to Duplex 2205?
EN 1.4462 / X2CrNiMoN22-5-3 is the commonly cross-referenced European Duplex 2205 designation. However, exact equivalence should be verified against the applicable product standard and certification.
Is Duplex 2205 magnetic?
Yes. Because Duplex 2205 contains a significant ferritic phase, it is normally magnetic, unlike fully austenitic grades such as 304 or 316.
What is the difference between ASTM A240 and ASTM A480?
ASTM A240 primarily specifies the material requirements for stainless plate, sheet and strip. ASTM A480 provides general requirements applicable to flat-rolled stainless products, including dimensional tolerances and general manufacturing requirements.
Can S31803/S32205 plate be supplied with ASTM A923 testing?
Yes, ASTM A923 testing can be specified as an additional project requirement where verification against detrimental intermetallic phases is required.
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Duplex 2205 Stainless Steel Plate Supplier & Exporter
We supply and export ASTM A240 UNS S31803 / S32205 Duplex Stainless Steel Plate for pressure vessel, oil & gas, offshore, chemical, marine and industrial applications.
Hot-rolled and cold-rolled products, custom dimensions and project-specific requirements such as EN 10204 3.1 certification, PMI, ferrite measurement, ASTM A923, ASTM G48 and third-party inspection can be supported when specified and commercially available.
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