Duplex Steel Pipes
Duplex Steel Pipes are high-strength, corrosion-resistant pipes made from a dual-phase microstructure consisting of approximately equal parts of austenite and ferrite. This unique combination gives duplex steel superior mechanical properties and enhanced resistance to stress corrosion cracking, pitting, and crevice corrosion, especially in harsh environments. Duplex pipes offer higher strength than standard austenitic stainless steels while maintaining good weldability and toughness. They are widely used in industries such as oil & gas, chemical processing, desalination, and marine engineering, where strength, durability, and corrosion resistance are critical. Common grades include UNS S31803 (Duplex 2205) and UNS S32205, and they are available in seamless, welded, and fabricated forms to suit a wide range of applications.
Duplex Steel Pipes - Specifications
| Parameter | Description / Options |
|---|---|
| Material Grades | UNS S31803, UNS S32205, 1.4462, ASTM A790, ASTM A928 |
| Standards | ASTM A790 / A789 (Seamless & Welded), ASTM A928 (Welded with filler), ASME SA790 |
| Types | Seamless, Welded, ERW, EFW, Fabricated |
| Sizes | 1/2" NB to 24" NB (DN15 to DN600) or custom |
| Thickness | Sch 10S, 20, 40S, 80S, 160, XXS, or as required |
| Length | Single Random, Double Random, Cut Lengths |
| Surface Finish | Pickled, Annealed & Pickled, Polished, Sand Blasted |
| End Connections | Plain End, Beveled End, Threaded |
| Heat Treatment | Solution Annealed at 1020–1100°C followed by rapid cooling |
| Testing | Hydrostatic, Eddy Current, PMI, Ultrasonic, Radiographic, Visual & Dimensional |
| Corrosion Resistance | Excellent resistance to pitting, crevice, and stress corrosion in chloride-containing environments |
| Applications | Oil & Gas, Petrochemicals, Water Treatment, Marine, Pulp & Paper, Chemical Processing |
Mechanical Properties
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HB) |
|---|---|---|---|---|
| UNS S31803 | 620 - 880 | 450 (min) | 25 (min) | ≤ 290 |
| UNS S32205 | 620 - 880 | 450 (min) | 25 (min) | ≤ 290 |
| 1.4462 (EN 10216-5) | 620 - 850 | ≥ 450 | ≥ 25 | ≤ 290 |
Chemical Composition
| Grade | C (%) | Mn (%) | Si (%) | P (%) | S (%) | Cr (%) | Ni (%) | Mo (%) | N (%) | Others |
|---|---|---|---|---|---|---|---|---|---|---|
| UNS S31803 | ≤ 0.03 | ≤ 2.00 | ≤ 1.00 | ≤ 0.030 | ≤ 0.020 | 21.0 – 23.0 | 4.5 – 6.5 | 2.5 – 3.5 | 0.14 – 0.20 | Fe (Balance) |
| UNS 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 | Fe (Balance) |
| 1.4462 (X2CrNiMoN22-5-3) | ≤ 0.03 | ≤ 2.00 | ≤ 1.00 | ≤ 0.035 | ≤ 0.015 | 21.0 – 23.0 | 4.5 – 6.5 | 2.5 – 3.5 | 0.10 – 0.22 | Fe (Balance) |