Super Duplex 2507 Seamless Pipe & Tube
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Super duplex 1.4410 – when duplex is not enough
1.4410 (X2CrNiMoN25-7-4, UNS S32750, commonly called 2507) is a super duplex stainless steel with a ferritic-austenitic microstructure. Compared with standard duplex 1.4462, it contains more chromium, molybdenum and nitrogen, giving a pitting resistance equivalent number (PREN) above 40. The steel resists pitting and crevice corrosion in seawater, including warmer water, as well as chloride stress corrosion cracking. Its yield strength is at least approx. 550 MPa – more than twice that of 316L. How PREN is calculated is explained in the article PREN – pitting resistance of stainless steel.
Chemical composition of 1.4410
| Grade | C | Cr | Ni | Mo | N |
|---|---|---|---|---|---|
| 1.4410 / 2507 | ≤ 0.030 | 24.0–26.0 | 6.0–8.0 | 3.0–4.5 | 0.24–0.35 |
| 1.4462 / 2205 (for comparison) | ≤ 0.030 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.10–0.22 |
Values in wt. % per EN 10088. Equivalents: 1.4410 = X2CrNiMoN25-7-4 = UNS S32750; pipe and tube per ASTM A789 / A790.
Sizes in stock
We carry super duplex pipe and tube in inch sizes 26.67 × 2.87 mm (¾″), 48.26 × 3.68 mm (1½″) and 114.3 × 3.05 and 114.3 × 6.02 mm (4″), in lengths from 10 cm to 3 m. We cut any tube to length. Other duplex diameters and walls are in the duplex pipe & tube subcategory.
Applications and fabrication
Super duplex is used on offshore platforms and ships (seawater, firewater and hydraulic systems), in reverse osmosis desalination plants, in seawater-cooled heat exchangers and in the chemical and pulp industries. More on steel for marine service in the article stainless steel offshore. Welding requires 2594 filler and strict heat input control; long-term service above approx. 250 °C (480 °F) is not recommended.
Duplex, super duplex or 316L?
In cool water and moderate chlorides, duplex 1.4462 / S31803 pipe & tube is usually sufficient, and in chloride-free media, 316L pipe & tube. In duplex we also offer duplex round bar and duplex 1.4462 elbows. Other pipe and tube is in the Seamless tubes and hollow bars category.