High Quality Duplex Steel S31803 | S32205 Pipes & Tubes
Seamless • Welded • Durable & Precise
Get a QuoteWhat is Duplex Stainless Steel S31803 & S32205?
Duplex Stainless Steel S31803 and S32205 are nitrogen-enhanced duplex alloys known for their high strength, excellent resistance to stress corrosion cracking, and superior resistance to pitting and crevice corrosion. These grades combine the beneficial properties of both austenitic and ferritic stainless steels, making them ideal for demanding environments such as chemical processing, marine applications, and oil & gas industries.
Duplex S31803
Chromium (Cr)
Nickel (Ni)
Molybdenum (Mo)
Carbon (C) Max
Manganese (Mn) Max
Silicon (Si) Max
Phosphorus (P) Max
Sulfur (S) Max
Nitrogen (N)
Iron (Fe)
Duplex S32205
Chromium (Cr)
Nickel (Ni)
Molybdenum (Mo)
Carbon (C) Max
Manganese (Mn) Max
Silicon (Si) Max
Phosphorus (P) Max
Sulfur (S) Max
Nitrogen (N)
Iron (Fe)
Types of Duplex S31803 & S32205 Pipes & Tubes
Ratnadeep Steel & Engg. Co. manufactures high-performance Duplex S31803 and S32205 seamless and welded pipes & tubes, engineered to deliver outstanding strength, durability, and corrosion resistance across challenging industrial environments.
Seamless pipes and tubes are produced from solid billets to ensure uniform strength and structural integrity. Their excellent resistance to stress corrosion cracking and superior mechanical strength make them suitable for high-pressure, high-temperature, and corrosive conditions such as in petrochemical, offshore, and desalination plants.
Welded pipes and tubes offer cost-effective solutions for large-scale applications while maintaining excellent corrosion resistance and mechanical performance. They are widely used in chemical processing, structural frameworks, and general engineering sectors where both strength and reliability are essential.
Specification of Duplex Steel S31803/S32205 Seamless & Welded Pipes And Tubes
| Specification | Details |
|---|---|
| Duplex Steel Pipe Specification | ASTM A790 / ASME SA790 |
| Duplex Steel Tube Specification | ASTM A789 / ASME SA789 |
| Grade | UNS S31803, S32205 |
| Size | ½” NB – 24″ NB |
| Thickness Range | 0.3mm – 50 mm, SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS |
| Outer Diameter | 6.0-630mm |
| Type | Seamless / ERW / Welded / Fabricated Pipes |
| Form | Round, Square, Rectangular, Oval, Hydraulic Etc |
| Length | Single Random, Double Random & Required Length |
| End | Plain End, Beveled End, Threaded |
| End Protection | Plastic Caps |
| Delivery Condition | Annealed and Pickled, Polished, Bright Annealed, Cold Drawn |
| Inspection, Test Reports | Mill Test Certificates, EN 10204 3.1, Chemical Reports, Mechanical Reports, PMI Test Reports, Visual Inspection Reports, Third Party Inspection Reports, NABL Approved Lab Reports, Destructive Test Report, Non Destructive Test Reports |
| Packing | Packed in Wooden Boxes, Plastic Bags, Steel Strips Bundled, or as per Customers Requests |
| Specials | Sizes and Specifications other than above can be manufactured on request |
Chemical Composition of Duplex Steel S31803/S32205 Pipes and Tubes
| Element | S31803 (%) | S32205 (%) |
|---|---|---|
| Carbon (C) | 0.030 max | 0.030 max |
| Manganese (Mn) | 2.00 max | 2.00 max |
| Phosphorus (P) | 0.030 max | 0.030 max |
| Sulfur (S) | 0.020 max | 0.020 max |
| Silicon (Si) | 1.00 max | 1.00 max |
| Chromium (Cr) | 21.00 – 23.00 | 22.00 – 23.00 |
| Nickel (Ni) | 4.50 – 6.50 | 4.50 – 6.50 |
| Molybdenum (Mo) | 2.50 – 3.50 | 3.00 – 3.50 |
| Nitrogen (N) | 0.08 – 0.20 | 0.14 – 0.20 |
| Iron (Fe) | Balance | Balance |
Mechanical Properties of Duplex Steel S31803/S32205 Pipes and Tubes
| Grade | Tensile Strength min (MPa) | Yield Strength (0.2% Offset) min (MPa) | Elongation (% in 2″) min | Hardness max |
|---|---|---|---|---|
| S31803 | 620 | 450 | 25 | Rockwell C (30) Brinell (290) |
| S32205 | 655 | 485 | 25 | Rockwell C (30) Brinell (293) |
Physical Properties of Duplex Steel S31803/S32205 Pipes and Tubes
| Grade | Density (kg/m³) | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion (μm/m°C) | Thermal Conductivity (W/m.K) | Specific Heat 0-100°C (J/kg.K) | Electrical Resistivity (nΩ.m) |
|---|---|---|---|---|---|---|
| S31803/S32205 | 7800 | 200 | 13.0 (0-100°C) 13.5 (0-200°C) 14.0 (0-300°C) |
19.0 (at 100°C) 20.5 (at 200°C) 22.0 (at 300°C) |
450 | 850 |
Equivalent Grades for Duplex Steel S31803/S32205 Pipes and Tubes
| STANDARD | WERKSTOFF NR. | UNS | JIS | AFNOR | BS | GOST | EN |
|---|---|---|---|---|---|---|---|
| S31803 | 1.4462 | S31803 | – | UR45N | 318S13 | – | X2CrNiMoN22-5-3 |
| S32205 | 1.4462 | S32205 | – | UR45N | 318S13 | – | X2CrNiMoN22-5-3 |
💡 Practical Difference in Use
Use S31803 when: standard duplex properties are sufficient with good corrosion resistance and mechanical strength.
→ Example: chemical processing equipment, heat exchangers, water treatment systems.
Use S32205 when: enhanced corrosion resistance and higher strength are required in more aggressive environments. → Example: offshore oil & gas applications, seawater systems, chemical tankers, desalination plants.
Uses of Duplex S31803/S32205 Stainless Steel Pipes
The uses are defined by their superior strength, excellent stress corrosion cracking resistance, and good corrosion resistance. Pipes are used in demanding applications where both mechanical strength and corrosion resistance are critical.
- High-Pressure and High-Temperature Systems: Duplex pipes handle higher pressures and temperatures than standard austenitic grades due to their superior mechanical strength.
- Aggressive Chemical Environments: Used for transporting corrosive chemicals, acids, and process streams where standard stainless steels would fail.
- Marine and Offshore Applications: Their excellent resistance to chloride-induced corrosion makes them ideal for seawater systems and offshore platforms.
When to Choose Standard Duplex vs. Super Duplex?
This is a critical decision for engineers. While both offer excellent strength and corrosion resistance, Super Duplex provides enhanced performance in the most demanding environments at a higher cost.
Choose S31803 when:
- Good corrosion resistance is required but not extreme environments
- Budget considerations are important
- Moderate chloride exposure (up to 1000-2000 ppm)
- General chemical processing applications
- Cost-effective solution for most industrial applications
Choose S32205 when:
- Severe chloride environments (seawater, high chloride concentrations)
- Higher pitting and crevice corrosion resistance required
- Offshore and subsea applications
- Higher mechanical strength needed for extreme pressure conditions
- Critical applications where failure is not an option
Key Performance Differences: S31803 vs S32205
S31803 (Standard Duplex)
- PREN: 33-34
- Yield Strength: 450 MPa min
- Pitting Resistance: Good
- Chloride Limit: Up to 1000-2000 ppm
- Cost: More economical
- Applications: Chemical plants, heat exchangers, water systems
S32205 (Super Duplex)
- PREN: 38-40
- Yield Strength: 550 MPa min
- Pitting Resistance: Excellent
- Chloride Limit: Up to 10,000+ ppm
- Cost: Premium
- Applications: Seawater, offshore, desalination
Industries That Use Duplex S31803/S32205 Stainless Steel Pipes
Duplex stainless steel pipes are essential in industries where both corrosion resistance and mechanical strength are paramount. Here are the key industries:
This is the largest consumer of duplex stainless steel pipes, especially in offshore and subsea applications.
Uses
Flow lines, risers, process piping, separator internals, and heat exchanger tubing in both upstream and downstream operations.
Material Choice
S31803: Onshore processing, sweet service
S32205: Offshore platforms, subsea systems, sour service
Duplex pipes handle aggressive chemicals and high temperatures in processing plants.
Uses
Reactor piping, distillation columns, heat exchanger tubes, and transfer lines for corrosive chemicals and acids.
Material Choice
S31803: General chemical processing, moderate acids
S32205: Highly corrosive environments, concentrated acids
Seawater handling requires materials that can withstand extreme chloride exposure.
Uses
Seawater intake lines, high-pressure RO membranes, brine handling systems, and water distribution networks.
Material Choice
S31803: Brackish water, low chloride environments
S32205: Seawater reverse osmosis, high chloride brines
Marine environments demand materials that can withstand saltwater corrosion.
Uses
Seawater cooling systems, ballast water piping, exhaust scrubber systems, and structural components.
Material Choice
S31803: Coastal applications, moderate marine exposure
S32205: Full seawater immersion, offshore structures
The demanding chemical environments in pulp processing require robust materials.
Uses
Digester piping, bleach plant equipment, black liquor lines, and chemical recovery systems.
Material Choice
S31803: Most pulp processing applications
S32205: High chloride bleach plants, aggressive chemical recovery
Both conventional and nuclear power plants use duplex pipes in critical systems.
Uses
Condenser tubing, feedwater systems, cooling water circuits, and flue gas desulfurization systems.
Material Choice
S31803: Freshwater cooling, general service
S32205: Seawater cooling, high chloride FGD systems
Transporting aggressive chemicals requires robust piping systems.
Uses
Cargo piping systems, loading/unloading arms, tank internals, and vent systems in chemical carriers.
Material Choice
S31803: Moderate chemicals, organic compounds
S32205: Highly corrosive chemicals, chlorides, acids
Aggressive processing environments with abrasive and corrosive materials.
Uses
Slurry transport lines, processing equipment, acid leaching systems, and tailings management.
Material Choice
S31803: General mineral processing, moderate acids
S32205: High chloride leaching, aggressive chemical processing
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