Products Description
Product Specifications
| Standards | ASTM A790 / ASME SA790 |
| Steel Grades | UNS S31803, UNS S32205, UNS S32750 |
| Equivalent Standards | EN 1.4462 (2205 Duplex), EN 1.4410 (2507 Super Duplex), DIN X2CrNiMoN22-5-3, X2CrNiMoN25-7-4 |
| Outer Diameter (OD) | 6 mm – 630 mm (seamless)8 mm - 1800 mm (welded) |
| Wall Thickness (WT) | 0.5 mm – 55 mm |
| Length | 6 / 12 m |
| Surface Treatment | Pickled & passivated |
| Production Process | Hot extrusion, cold drawing, cold rolling,TIG / Laser welding |
| Condition | Solution annealed + pickled |
The PREN value of S32205 can reach 34–36, and the PREN value of S32750 exceeds 41, far higher than the 24–26 of 316L. ASTM A790 S31803 S32750 S32205 Duplex Steel Pipe exhibits excellent corrosion resistance for heat exchangers cooling seawater, brackish water, or acidic process fluids.
Austenitic stainless steels 304/316L are highly susceptible to stress corrosion cracking (SCC) under conditions containing trace amounts of chloride ions and temperatures exceeding 50°C. However, the duplex structure makes S32205/S32750 virtually immune to chloride-induced SCC in high-chlorine, medium-high temperature environments (S32750 can reach above 150°C).
Customized Services
- TORICH offers fixed-length cutting and can provide customized end treatments-such as chamfering, beveling, swaging, flaring, bending, and drilling-to facilitate automated welding or tube-to-tubesheet assembly (including contact expansion or full expansion).
- For high-pressure applications, fully solution-annealed treatments are available to enhance pressure-bearing stability; for cryogenic applications, processes optimized for low-temperature toughness can be specified to prevent brittle fracture; and for welded tubes, weld seam leveling and polishing are available to eliminate heat-transfer dead zones.
- We also provide mirror-finish polishing (Ra ≤ 0.4 μm) for both inner and outer surfaces, as well as bright finishes achieved through precision rolling.
Chemical Composition
| Element | Carbon | Manganese | Silicon | Phosphorus | Sulfur | Chromium | Nickel | Molybdenum | Nitrogen |
| S31803 | ≤0.03 | ≤2.00 | ≤1.00 | ≤0.030 | ≤0.020 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 |
| S32205 | ≤0.03 | ≤2.00 | ≤1.00 | ≤0.030 | ≤0.020 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 |
| S32750 | ≤0.03 | ≤1.20 | ≤0.80 | ≤0.035 | ≤0.020 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 0.24–0.32 |
Mechanical Properties
| Property | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HB) |
| S31803 | ≥620 | ≥450 | ≥25 | ≤290 |
| S32205 | ≥620 | ≥450 | ≥25 | ≤290 |
| S32750 | ≥795 | ≥550 | ≥25 | ≤310 |
Possible Alternative Grades
- For cooling water environments with low chloride content, 316L stainless steel is a suitable choice; it is more cost-effective and easier to fabricate than duplex stainless steel.
- For sulfuric acid environments and chemical processing equipment, 904L stainless steel is an option; it offers excellent corrosion resistance, though it has higher material costs and lower strength than duplex stainless steel.
- For extremely corrosive environments, Nickel Alloy 625 can be selected; it offers superior corrosion resistance to duplex stainless steel but at a very high cost.
application areas
- Industrial Heat Exchange Equipment: Shell-and-tube heat exchangers, plate heat exchangers, tubular condensers, waste heat recovery heat exchangers, and core piping for steam condensation equipment
- Seawater Desalination Industry: Seawater heat exchange condensers, seawater circulating cooling piping, heat exchange components for reverse osmosis equipment, and coastal power plant condensation systems
- Petrochemical Industry: Heat exchangers for acidic/alkaline chemical media, oil and gas condensation recovery equipment, petrochemical circulating cooling systems, and desulfurization/denitrification heat exchange units
- Power and Energy Industry: Condenser piping for thermal, hydroelectric, and nuclear power plant auxiliaries; generator cooling heat exchangers; and waste heat exchange equipment for new energy applications
- HVAC and Refrigeration Industry: Condensers for industrial chillers, central air conditioning heat exchange piping, and cryogenic refrigeration heat exchange equipment
Products Show
Testing Equipment
Factory Equipment
Pickling equipment
Polishing equipment
Cold drawing equipment
Products Package
FAQ
Q: What is the difference between S31803 and S32205, and why is S32205 currently preferred?
A: S32205 raises the minimum nitrogen content to 0.14%, ensuring sufficient austenite retention in the weld heat-affected zone (HAZ) and preventing a decline in corrosion resistance. Consequently, it has completely superseded S31803 as the standard grade for 2205 duplex stainless steel.
Q: Can duplex stainless steel pipes be used directly for seawater cooling?
A: Yes. S32205 is suitable for low-temperature, flowing seawater applications, whereas S32750 is better suited for warm, stagnant, or polluted seawater environments.
Q: Do you supply U-tubes, and what is the minimum bending radius?
A: Yes, we supply U-tubes that comply with TEMA and HEI standards. The minimum bending radius is generally defined as a centerline radius of at least 1.5 times the outer diameter; however, this can be optimized based on material condition and wall thickness to prevent cracking and excessive wall thinning.
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