Henan TOM Intelligent Technology Co., Ltd. has completed shipment of a major order of ASTM A790 UNS S31803 (2205 duplex stainless steel) seamless pipe to a leading EPC contractor in the Middle East. The material will be used in a large-scale seawater desalination plant and associated offshore water-injection facilities, where continuous exposure to chlorides makes ordinary austenitic stainless and carbon steel unviable.
This delivery underscores TOM's ability to supply corrosion-critical duplex grades with full mill traceability and third-party inspection-exactly what regulated water and energy projects require.
Why 2205 duplex (UNS S31803)?
UNS S31803 is the original 2205 duplex composition (≈22% Cr, 3% Mo, 5–6% Ni, ~0.15% N). It combines an austenitic–ferritic microstructure that delivers two decisive advantages in seawater service:
Roughly twice the yield strength of 316L (min. 450 MPa vs ~215 MPa), allowing thinner walls, lighter spools, and lower freight and welding cost.
Excellent chloride resistance - PREN ≈ 34–35, far above 316L (~25), with strong immunity to chloride stress-corrosion cracking (SCC) that routinely defeats austenitic grades in hot, concentrated brines.
PREN = %Cr + 3.3 × %Mo + 16 × %N ≈ 34–35 for 2205 duplex.
Product at a glance
| Item | Specification |
|---|---|
| Standard | ASTM A790 / A789 (duplex seamless pipe & tube) |
| Grade | UNS S31803 (2205 duplex stainless steel) |
| Manufacturing | Seamless, hot-finished, solution-annealed & water-quenched |
| Surface | Pickled & passivated; 100% PMI verified |
| Ends | Plain ends, beveled to ASME B16.25 (30°–35°) |
| Heat treatment | Solution annealed ≥ 1040 °C, rapid quench |
| Documents | EN 10204 3.1 mill certs; SGS third-party inspection; EN 10204 3.2 available |
Shipment details (export list)
| OD (inch) | OD (mm) | Wall (SCH) | Length | Qty (pcs) |
|---|---|---|---|---|
| 3" | 88.9 | 5.49 mm (40S) | 6.0 m | 200 |
| 4" | 114.3 | 6.02 mm (40S) | 6.0 m | 150 |
| 6" | 168.3 | 7.11 mm (40S) | 6.0 m | 120 |
| 8" | 219.1 | 8.18 mm (40S) | 6.0 m | 80 |
| 10" | 273.1 | 9.27 mm (40S) | 6.0 m | 60 |
| 12" | 323.9 | 9.53 mm (40S) | 6.0 m | 45 |
Quality control & testing
Because duplex is sensitive to detrimental intermetallic phases if improperly heat-treated, every heat was verified before shipment:
100% Positive Material Identification (PMI) by OES/ XRF.
Hydrostatic test per ASTM A999 / customer spec.
Ultrasonic (UT) and eddy-current (ET) inspection of seamless bodies.
Intermetallic-phase check per ASTM A923 Method C and pitting check per ASTM G48.
Flattening / flange testing and charpy impact at −46 °C where specified.
About the supplier
Henan TOM Intelligent Technology Co., Ltd. has manufactured precision steel pipe, flange and fitting solutions since 1999, with OEM/ODM capability and mill-direct sourcing of austenitic, duplex and super-duplex stainless grades. In-house machining of flanges, fittings and prefabricated spools lets TOM deliver a complete, certified package-supported by PMI, hydrostatic and NDT testing and third-party inspection on request.
Conclusion
The A790 UNS S31803 seamless pipe shipment demonstrates that a corrosion-resistant, high-strength duplex material-properly heat-treated and fully documented-is the right answer for chloride-laden desalination and offshore service. TOM continues to support EPCs and end users worldwide with grade selection, mill certificates and on-time export delivery.
