Duplex Steel S31803 / S32205 Sheets & Plates
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Duplex Steel S31803 / S32205 Sheets & Plates Supplier in Mumbai, India – ASTM A240
Nicorex Alloys is an ISO 9001 and ISO 14001 certified importer, stockist, and supplier based in Mumbai, India. We supply Duplex Steel S31803 / S32205 sheets and plates manufactured to ASTM A240 / ASME SA240, with every item dual-certified S32205/S31803.
Duplex S31803 and S32205 are ferritic-austenitic flat-rolled products sharing Werkstoff Nr. 1.4462, marketed globally as Duplex 2205. S31803 is the legacy UNS designation with broader composition ranges (PREN 31–35). S32205 is the modern preferred specification with tighter controls on Cr (≥22%), Mo (≥3.0%), and N (≥0.14%), guaranteeing PREN ≥34. Material certified to S32205 automatically meets S31803, but not vice versa. The balanced 50/50 austenite-ferrite microstructure delivers roughly twice the yield strength of 316L (448 MPa vs 170 MPa) with high chloride pitting and stress corrosion cracking resistance. Sheet thickness ranges from 0.5 to 6.0 mm; plate thickness ranges from 6.0 to 150 mm. Widths span 1000 to 2500 mm. Solution annealing at 1040–1100°C with rapid water quench restores the correct phase balance after fabrication. Available finishes include No.1, 2B, 2D, BA, No.4, and mirror polish.
Core applications cover pressure vessel shells, heat exchanger tubesheets, offshore structural plate, storage tank linings, pulp and paper digesters, and FGD scrubber housings. Duplex 2205 is NACE MR0175 compliant for sour-service environments. Every product we supply is backed by mill test certificates per EN 10204/3.1.
Duplex S31803 / S32205 Sheet & Plate Specifications
Specifications of Duplex S31803 / S32205 sheets and plates conform to these standards and dimensional ranges:
| Standard | ASTM A240 / ASME SA240 |
|---|---|
| Forging Grades | F51 (S31803) / F60 (S32205) per ASTM A182 |
| Sheet Thickness | 0.5 mm to 6.0 mm |
| Plate Thickness | 6.0 mm to 150 mm (S32205) / up to 100 mm (S31803) |
| Width | 1000, 1250, 1500, 2000, 2500 mm |
| Length | 2000, 2500, 3000, 6000 mm, custom cut |
| Surface Finish | No.1 (HR), 2B, 2D, BA, No.4 Brushed, No.8 Mirror |
| Edge | Mill Edge, Slit Edge |
| Hardness | 293 HB max / 31 HRC max |
| Condition | Solution Annealed & Pickled |
S32205 tightens composition limits for Cr (22–23%), Mo (3.0–3.5%), and N (0.14–0.20%), giving higher PREN consistency. All Nicorex stock is dual-certified. For new projects, always specify S32205.
S31803 vs S32205 – Which to Specify for Sheet & Plate
Understanding the relationship between S31803 and S32205 helps procurement teams order correctly:
| Parameter | S31803 (F51) | S32205 (F60) |
|---|---|---|
| UNS | S31803 | S32205 |
| Chromium Range | 21.0–23.0% | 22.0–23.0% |
| Molybdenum Range | 2.5–3.5% | 3.0–3.5% |
| Nitrogen Range | 0.08–0.20% | 0.14–0.20% |
| PREN Range | 31–35 (variable) | 34–36 (guaranteed ≥34) |
| Certification | S31803 only | Dual S32205 + S31803 |
| ASME Reference | Cited in older codes | Preferred for new projects |
| Plate Thickness | Up to 100 mm | Up to 150 mm |
| Recommendation | Only when mandated by existing code | All new procurement |
For new procurement, always specify S32205. Use S31803 only when mandated by existing ASME code references. Always request dual-certified S32205/S31803 material.
Chemical Composition of Duplex S31803 / S32205 Sheet & Plate
Chemical composition of Duplex S31803 / S32205 Sheet & Plate as per ASTM A240 are provided in the table below:
| Specification | Carbon (C) | Chromium (Cr) | Nickel (Ni) | Molybdenum (Mo) | Nitrogen (N) | Manganese (Mn) | Silicon (Si) | Phosphorus (P) | Sulfur (S) | Iron (Fe) |
|---|---|---|---|---|---|---|---|---|---|---|
| S31803 Range (%) | 0.030 max | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 | 2.0 max | 1.0 max | 0.030 max | 0.020 max | Balance |
| S32205 Range (%) | 0.030 max | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 | 2.0 max | 1.0 max | 0.030 max | 0.020 max | Balance |
PREN = %Cr + 3.3×%Mo + 16×%N. S31803 PREN ranges from 31 to 35. At the lower end (Cr 21%, Mo 2.5%, N 0.08%), PREN drops to ~31. S32205 guarantees PREN ≥34 (typical ~35). Higher nitrogen strengthens the austenite phase and improves HAZ toughness. Low carbon (≤0.03%) prevents sensitisation during welding.
Mechanical Properties of ASTM A240 Duplex S31803 / S32205 Sheet & Plate
S31803 and S32205 share identical mechanical minimums as per ASTM A240. The difference is primarily the chemical composition:
| Specification | Yield Strength (0.2%) | Tensile Strength | Elongation in 50 mm | Hardness (Brinell) | Hardness (Rockwell C) |
|---|---|---|---|---|---|
| ASTM A240 Minimum | 448 MPa (65 ksi) | 621 MPa (90 ksi) | 25% | 293 HB max | 31 HRC max |
| Typical Value | 510 MPa (74 ksi) | 724 MPa (105 ksi) | 30% | — | 19 HRC |
Elevated-temperature properties:
The 448 MPa minimum yield is nearly double that of 316L (170 MPa), allowing thinner plate designs for pressure vessels under ASME BPVC Section VIII. Embrittlement risk above 300°C limits service to –50°C to +300°C.
| Temperature | Yield Strength | Tensile Strength |
|---|---|---|
| 50°C (122°F) | 414 MPa | 662 MPa |
| 100°C (212°F) | 358 MPa | 621 MPa |
| 200°C (392°F) | 310 MPa | 572 MPa |
| 300°C (572°F) | 283 MPa | 559 MPa |
Physical Properties of Duplex S31803 / S32205 Sheets & Plates
Physical properties are identical for S31803 and S32205. Important physical properties like density, melting point, elastic modulus, and more are provided below:
| Specification | Density | Melting Range | Elastic Modulus | Thermal Expansion (0–100°C) | Thermal Conductivity (100°C) | Specific Heat (0–100°C) | Electrical Resistivity | Magnetic Permeability | Poisson’s Ratio |
|---|---|---|---|---|---|---|---|---|---|
| Typical Value | 7800 kg/m³ (7.8 g/cm³ / 0.278 lb/in³) | 1385–1445°C (2525–2630°F) | 190 GPa (27.6 × 10⁶ psi) | 13.7 µm/m/°C | 19 W/m·K | 418 J/kg·K | 850 nΩ·m | Ferromagnetic (~50% ferrite phase) | 0.3 |
Thermal conductivity at 19 W/m·K is ~30% higher than 316L (14.2 W/m·K), improving heat transfer in exchanger plates. Lower thermal expansion (13.7 vs 16.0 µm/m/°C) reduces weld distortion. Unlike austenitic 316L, Duplex 2205 is magnetic due to ~50% ferrite, which affects NDE methods.
Duplex S31803 / S32205 Sheet & Plate Equivalent Grades
Equivalent designations for Duplex S31803 / S32205 sheet and plate across different international standards are mentioned below:
| Specification | UNS | EN / Werkstoff Nr. | EN Name | AFNOR (France) | JIS (Japan) |
|---|---|---|---|---|---|
| Designation | S31803 (legacy) / S32205 (preferred modern) | 1.4462 (shared by both) | X2CrNiMoN 22-5-3 | Z3 CrNi 22.05 AZ | SUS 329J3L |
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Available Forms of Duplex S31803 Sheet & Plate
Duplex S31803 / S32205 flat products are supplied dual-certified in the following forms:
Duplex S31803 Hot Rolled Plate
Duplex S32205 Cold Rolled Sheet
Duplex S31803 Coil
Duplex S31803 Strip
Duplex S31803 Foil
Duplex S31803 Shim Sheet
DSS S31803 Chequered Plate
Duplex S31803 Perforated Sheet
Corrosion Resistance of Duplex S31803 Sheet & Plate
PREN (%Cr + 3.3×%Mo + 16×%N) determines pitting resistance. S32205 holds PREN ≥34 with a typical CPT of ~35°C in 1M NaCl. S31803 PREN can fall to ~31 at the lower composition limit. Both surpass 316L (~15°C CPT). CCT in 10% FeCl₃ reaches ~15°C versus below 0°C for 316L.
Both grades resist chloride SCC up to ~150°C, where 304L and 316L fail above 60°C. The ferrite phase acts as a barrier to crack propagation. Corrosion rate data:
| Medium | Temperature | Corrosion Rate (mpy) |
|---|---|---|
| Wet-process phosphoric acid (Sol A) | 60°C | 3.1 |
| Wet-process phosphoric acid (Sol B) | 49°C | 3.9 |
| 20% H₂SO₄ | 60°C | <5 |
| Seawater (flowing) | Ambient | <1 |
Strong performance in organic acids, dilute H₂SO₄, and wet-process phosphoric acid. High corrosion fatigue strength suits cyclic-loaded equipment.
Hot Working, Cold Forming & Heat Treatment of Duplex S31803
Hot form at 955–1230°C. Above 1230°C, excessive ferrite causes hot tearing. Below 955°C, sigma and chi phases form rapidly and cause embrittlement. Always follow hot work with a solution anneal at ≥1040°C plus water quench.
Cold forming below 315°C is recommended. Expect double the forming loads compared to 316L. Intermediate annealing is needed beyond 10% cold work. Solution annealing at 1040–1120°C with rapid water quench restores the 50/50 phase balance. No stress relief below 1040°C.
Weldable by GTAW, GMAW, SMAW, SAW, PAW, and FCW. Specify ER2209 (wire) or E2209 (electrode), containing ~8.5–10.5% Ni to promote austenite in weld metal. Interpass: ≤150°C. No preheat or PWHT required. Use Ar + 2% N₂ shielding for GTAW. ASTM A923 testing verifies the absence of intermetallic phases. For dissimilar joints to carbon steel, specify ER309LMo or ERNiCrMo-3.
Industries Using Duplex S31803 Sheet & Plate
Duplex S31803 / S32205 sheets and plates serve industries where high strength, chloride resistance, and cost savings over nickel alloys are required:
- Separator vessel shells, sour-service pressure vessels as per NACE MR0175, and subsea manifold housings. Specify S32205 to guarantee PREN ≥34 for sour-service applications.
- Reactor vessels, distillation column internals, and acid storage tanks. Effective in wet-process phosphoric acid, where 316L fails (>200 mpy vs 3.1 mpy for S32205).
- Structural members for offshore platforms, blast walls, deck plates, and ballast tank linings. PREN ≥34 (S32205) gives reliable pitting resistance in splash zones.
- MSF/MED evaporator shells, RO pressure vessel housings, and brine heater plates. Handles chloride levels up to 20,000 ppm below 60°C.
- Digesters, blow tanks, white liquor storage tanks, and bleaching equipment. Resists the combination of chlorides, caustic liquors, and temperature cycling in kraft pulp mills.
- Process vessels, tanks, and conveyor surfaces in 2B/BA finish. Higher strength than 316L allows a thinner gauge sheet and lighter equipment.
- FGD scrubber shells, absorber towers, and condenser tubing plates. Resists flue gas condensates with chloride contamination.
- Bridge decks, structural reinforcement in chloride-exposed environments, and tunnel linings. High yield strength reduces plate thickness for weight savings.
How to Order Duplex S31803 / S32205 Sheet & Plate
To place an order for Duplex S31803 / S32205 sheet & plate, provide the following details:
- Product Form (Sheet, Plate, Coil, Strip, Shim)
- Dimensions (Thickness × Width × Length in mm)
- Material Grade (Duplex Steel S31803 / UNS S31803 / F51)
- Standard (ASTM A240 / ASME SA240)
- Surface Finish (2B, 2D, No.1, BA, No.4, #8 Mirror)
- Edge Type (Mill Edge, Slit Edge, Trimmed)
- Quantity (number of pieces, kg, or MT)
- Additional Requirements (NACE MR0175 compliance, HIC/SSC testing, specific heat numbers)
- Documentation (MTC 3.1 per EN 10204, PMI report, third-party inspection certificate)
- Packaging (Standard wooden box / export-grade sea-worthy packing / ISPM 15 compliant)
- Delivery destination (domestic / international)
Frequently Asked Questions
What is the Difference Between S31803 and S32205?
Both are UNS designations for Duplex 2205 (Werkstoff 1.4462). S31803 allows Cr as low as 21.0%, Mo as low as 2.5%, and N as low as 0.08%, so PREN can drop to ~31. S32205 requires Cr ≥22.0%, Mo ≥3.0%, and N ≥0.14%, guaranteeing PREN ≥34. S32205 automatically meets S31803, but not the reverse. Specify S32205 for all new projects.
What is the Maximum Service Temperature for Duplex S32205 Plate?
Continuous service between –50°C and +316°C. Above 300–316°C, sigma and chi phases precipitate, causing loss of toughness and corrosion resistance. Below –50°C, the ductile-to-brittle transition of the ferrite phase limits safe operation.
What is the PREN of Duplex S31803 Plate?
PREN = %Cr + 3.3×%Mo + 16×%N. S31803 PREN ranges from 31 to 35, depending on heat chemistry. S32205 guarantees PREN ≥34 (typical ~35). This variability is the single most important technical difference between the two grades.
Is Duplex S31803 Sheet Magnetic?
Yes. Unlike fully austenitic grades (304L, 316L, 904L), Duplex S31803/S32205 sheets and plates are ferromagnetic due to ~50% ferrite phase. This affects NDE method selection and handling with magnetic lifting equipment.
What Welding Filler Metals are Recommended for S32205 Plate?
Specify ER2209 (wire for GTAW/GMAW) or E2209 (electrode for SMAW). These over-alloyed fillers contain ~8.5–10.5% Ni to promote austenite in weld metal. Use Ar + 2% N₂ shielding for GTAW. Interpass ≤150°C. No preheat or PWHT required. For dissimilar joints to carbon steel, specify ER309LMo or ERNiCrMo-3.