Built for extreme environments: high pressure, high chloride, high corrosion.
Duplex (22% Cr) and Super Duplex (25% Cr) stainless steels are the workhorses of modern offshore, subsea, desalination, chemical and power industries. These materials combine the best of two worlds:
Result:
Twice the strength of 304/316
Superior corrosion resistance in seawater & chlorides
High-pressure durability without heavy wall thickness
For engineering teams designing pipelines, risers, manifolds and corrosion-critical components, ASTM A789/A790 duplex tubes offer unmatched dependability.
Built for extreme environments: high pressure, high chloride, high corrosion.
Duplex (22% Cr) and Super Duplex (25% Cr) stainless steels are the workhorses of modern offshore, subsea, desalination, chemical and power industries. These materials combine the best of two worlds:
Result:
Twice the strength of 304/316
Superior corrosion resistance in seawater & chlorides
High-pressure durability without heavy wall thickness
For engineering teams designing pipelines, risers, manifolds and corrosion-critical components, ASTM A789/A790 duplex tubes offer unmatched dependability.
These are welded stainless-steel tubes manufactured from duplex alloys that contain a balanced austenite–ferrite microstructure.
They provide:
These materials outperform 316/317 stainless steel in nearly all severe environments.
Duplex alloys deliver approximately twice the yield strength of 316, enabling lower wall thickness, lower weight, and reduced overall cost for the same pressure rating.
| Alloy | PREN |
| 316L | ~25 |
| Duplex 2205 | ~35 |
| Super Duplex 2507 | >40–45 |
Super Duplex tubes resist stress cracking in seawater, chlorinated industrial water, high-pressure brine, and sour gas (Hâ‚‚S) environments.
| Standard | Covers | Use Case |
| ASTM A789 | Seamless & welded duplex tubes | Heat exchangers, condensers |
| ASTM A790 | Seamless & welded duplex pipe | Process piping, risers |
| OD Range | WT Range | Applications |
| 6 – 19.05 mm | 0.8 – 2.0 mm | Instrumentation, injection lines |
| 19.05 – 38.1 mm | 1.0 – 3.0 mm | Heat exchangers |
| 38.1 – 60.3 mm | 2.0 – 5.0 mm | Process piping |
| 60.3 – 114.3 mm | 3.0 – 8.0 mm | Offshore manifolds |
| 114.3 – 168.3 mm | 4.0 – 10.0 mm | Main headers |
| Grade | PREN | Resistance |
| 316L | ~25 | Moderate |
| Duplex 2205 | 34–36 | Very High |
| Super Duplex 2507 | 40–45 | Extreme |
| Alloy | INR/Kg | USD/Kg |
| Duplex 2205 | ₹550 – ₹800 | $7 – $11 |
| Lean Duplex | ₹480 – ₹720 | $6 – $9 |
| Super Duplex | ₹850 – ₹1,300 | $10 – $16 |
Q1. Difference between ASTM A789 & A790?
A789 covers tubes; A790 covers pipes.
Q2. Why duplex instead of 316?
Higher strength & superior chloride SCC resistance.
Q3. Is welded duplex reliable offshore?
Yes, with controlled welding & NDT.