At Namo Alloy, we are specialized providers of high-strength Duplex Stainless Steel Flanges, Fittings, and Fasteners. Combining the best properties of both Austenitic and Ferritic steels, Duplex grades like F51, S31803, and S32205 offer double the yield strength of standard stainless steels and exceptional resistance to localized corrosion. Our forged flanges and buttweld fittings are designed to survive the harsh chloride-rich conditions of offshore oil platforms, desalination plants, and chemical processing tanks. Furthermore, our Duplex Fasteners provide the critical clamping force needed in high-vibration marine environments without the risk of stress corrosion cracking. Every component is 100% mill-certified to ASTM A182, A815, and A479 standards, ensuring precision alloying for peak industrial reliability.
| Grade | Cr (Chromium) | Ni (Nickel) | Mo (Molybdenum) | N (Nitrogen) | Mn (Manganese) | Si (Silicon) | C (Carbon) | PREN (Min) |
|---|---|---|---|---|---|---|---|---|
| Duplex 2205 (S31803/S32205) | 22.0 - 23.0% | 4.5 - 6.5% | 3.0 - 3.5% | 0.14 - 0.20% | 2.0% Max | 1.0% Max | 0.03% Max | 35 |
| Super Duplex 2507 (S32750) | 24.0 - 26.0% | 6.0 - 8.0% | 3.0 - 5.0% | 0.24 - 0.32% | 1.2% Max | 0.8% Max | 0.03% Max | 40+ |
| Grade | Tensile Strength (MPa) min. | Yield Strength 0.2% Offset (MPa) min. | Elongation (%) min. | Hardness (Brinell) Max. | Impact Energy (KV ISO-V) |
|---|---|---|---|---|---|
| Duplex 2205 (F51) | 620 MPa | 450 MPa | 25% | 290 HB | 100 J @ -40°C |
| Super Duplex 2507 (F53) | 800 MPa | 550 MPa | 15% | 310 HB | 80 J @ -50°C |
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ASTM A182, ASME SA182 (F51, F53, F55, F60) |
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Flange Types
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Weld Neck, Slip-On, Blind, Lap Joint, Socket Weld, Threaded, Long Weld Neck |
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Class/Pressure
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150 LBS to 2500 LBS | PN6 to PN160 |
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Size Range
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1/2" to 24" NB (Standard) | Up to 48" (Large Diameter) |
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ASTM A815, ASME B16.9, B16.11, MSS SP-43 |
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90°/45° Elbows, Equal/Reducing Tees, Reducers, Stub Ends, Pipe Caps |
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Wall Thickness
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SCH 10S, 40S, 80S, 160, XXS |
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Pickled, Sand Blasted, Polished, Machined |
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ASTM A479, A193, A194 (S31803 / S32205 / S32750) |
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Components
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Hex Bolts, Heavy Hex Bolts, Stud Bolts, Nuts, Plain & Spring Washers |
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Dimensions
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Diameter: M6 to M100 | 1/4" to 4" Length: 10mm to 3000mm |
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Mechanical Tests
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Tensile Test, Hardness Test, Pitting Corrosion Test (ASTM G48) |
Marine & Offshore Quality: All Duplex Steel products are 100% PMI tested and supplied with EN 10204 3.1 Mill Test Certificates. Our inventory is fully compliant with NACE MR0175/ISO 15156 standards for use in oil and gas production environments involving H2S.
Namo Alloy is a leading stockist and global exporter of premium Stainless Steel, Carbon Steel, and High Nickel Alloys.
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