Erw Duplex Stainless Steel Pipe is super duplex stainless steel with 25% chromium, 4% molybdenum, and 7% nickel designed for demanding applications which require exceptional strength and corrosion resistance, such as chemical process, petrochemical, and seawater equipment. The steel has excellent resistance to chloride stress corrosion cracking, highthermal conductivity, and a low coefficient of thermal expansion.
Erw Duplex Stainless Steel Pipe grades have enhanced pitting and crevice corrosion resistance when compared with 300-series austeniticstainless steel or conventional duplex alloys. This can be attributed to the enhanced levels of chromium, molybdenum and nitrogen found in these materials. Alloy 2507 is the most common "super" duplex grade.
Composition of Erw Duplex Stainless Steel Pipe
| Grade | Super Duplex 2507 |
| UNS Designation | S32750 |
| Carbon (C) Max. | 0.030 |
| Manganese (Mn) Max. | 1.20 |
| Phosphorous (P) Max. | 0.035 |
| Sulphur (S) Max. | 0.020 |
| Silicon (Si) Max. | 0.80 |
| Chromium (Cr) | 24.0–26.0 |
| Nickel (Ni) | 6.0–8.0 |
| Molybdenum (Mo) | 3.0–5.0 |
| Nitrogen (N) | 0.24–0.32 |
| Iron (Fe) | Bal. |
| Copper (Cu) | 0.50 |
| Other Elements | — |
|Super Duplex 2507 Product Range
| Alloy | UNS Designation | Werkstoff NR. | Specifications* |
| Super Duplex 2507 | S32750 | 1.4410 | A/SA789, A/SA790 |
Physical Properties of Super Duplex 2507 Alloys in the Annealed Condition at -20°F to +100°F
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| Alloy | UNS | Spec. | psi | MPa | ksi | psi | MPa | ksi | Elongation in 2 in. (min.) % | Grain Size Req. | Max. Hardness | Modulus of Elasticity (x106 psi) | Mean Coefficient of Thermal Expansion (IN./IN./°F x 10-6) | Thermal Conductivity (BTU-in/ ft2-h-°F) |
| SuperDuplex2507 | S32950 | A789,A790 | 100,000 | 690 | 100 | 70,000 | 485 | 70 | 20 | — | 30.5 Rc | — | — | — |
| Super Duplex 2507 | S32750 | A789, A790 | 116,000 | 800 | 116 | 80,000 | 550 | 80 | 15 | — | 32 Rc | 27.5 | 7.2 | 98 |
