Duplex Steel Body Flange, ASTM A182 Grade F51 (UNS S31803), Suitable For Corrosive Environments
Duplex Steel Body Flange, ASTM A182 Grade F51 (UNS S31803), Suitable For Corrosive Environments
What is ASTM A182 F51 Flange?
A182 F51 duplex stainless steel is a compound stainless steel alloyed with 21% chromium, 2.5% molybdenum and 4.5% nickel-nitrogen. it has high strength, good impact toughness and good overall and localized resistance to stress corrosion. It has high strength, good impact toughness, and good overall and localized resistance to stress corrosion.The yield strength of A182 F51 duplex stainless steel is twice that of austenitic stainless steels, a characteristic that allows designers to reduce weight when designing products and gives this alloy a price advantage over 316 and 317L.
ASTM A182 F51 (UNS S31803) Body Flange is a forged duplex stainless steel flange designed for high-pressure piping systems. With a balanced microstructure of austenite and ferrite, it offers high strength, excellent corrosion resistance, and superior performance in chloride-rich, marine, and chemical environments. Commonly supplied as a Weld Neck Raised Face (WNRF) type, it is widely used in oil & gas, petrochemical, and offshore applications, meeting ASME and NACE standards.
Key Advantages of ASTM A182 F51 Flange
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High mechanical strength and pressure handling
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Exceptional corrosion resistance in chloride-rich and aggressive environments
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Long service life and reduced maintenance
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Balanced properties make it ideal for critical process piping systems
Chemical Composition of A182 F51 Flanges
| C | Mn | Si | P | S | Cr | Mo | Ni | N | Fe |
|---|---|---|---|---|---|---|---|---|---|
| 0.030 max | 2.00 max | 1.00 max | 0.030 max | 0.020 max | 22.0 – 23.0 | 3.0 – 3.5 | 4.50 – 6.50 | 0.14 – 0.20 | 63.72 min |
Mechanical Properties of A182 F51 Flanges
| Tesile | Requirements |
|---|---|
| Tensile Strength / min. MPa [ksi] | 620 [90] |
| Yield Strength / min. MPa [ksi] | 450 [65] |
| Elongation in 2", min. % | 25 |
| Reduction of Area, min. % | 45 |
Pressure-Temperature Rating for ASME B16.5 Flanges
| Temp, ℃ | Pressure-temperature rating for ASME B16.5 | ||||||
| 150 | 300 | 400 | 600 | 900 | 1500 | 2500 | |
| -29 to 38 | 20.0 | 51.7 | 68.9 | 103.4 | 155.1 | 258.6 | 430.9 |
| 50 | 19.5 | 51.7 | 68.9 | 103.4 | 155.1 | 258.6 | 430.9 |
| 100 | 17.7 | 50.7 | 67.5 | 101.3 | 152.0 | 253.3 | 422.2 |
| 150 | 15.8 | 45.9 | 61.2 | 91.9 | 137.8 | 229.6 | 382.7 |
| 200 | 13.8 | 42.7 | 56.9 | 85.3 | 128.0 | 213.3 | 355.4 |
| 250 | 12.1 | 40.5 | 53.9 | 80.9 | 121.4 | 202.3 | 337.2 |
| 300 | 10.2 | 38.9 | 51.8 | 77.7 | 116.6 | 194.3 | 323.8 |
Application of ASTM A182 F51 body Flange
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Offshore and onshore pipelines
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Subsea equipment
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Manifolds and risers
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Sour service environments (H₂S) – NACE-compliant
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Seawater cooling systems
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Ballast water treatment
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Desalination units
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Corrosion-resistant piping components
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