1/2" to 24" ASTM A182 F51 WNRF Flanges Class 150-2500 Corrosion Resistant Duplex Steel
ASTM A182 F51 WNRF Flanges | Duplex 2205 Raised Face Flanges Supplier | YUHONG
1. Duplex 2205 Flanges Overview: Superior Corrosion Resistance
ASTM A182 F51 WNRF (Welding Neck Raised Face) flanges combine high strength with exceptional chloride stress
corrosion cracking resistance. Manufactured from duplex stainless steel UNS S31803 (EN 1.4462), these flanges
deliver 2x the yield strength of 316L stainless steel while maintaining cost efficiency. Ideal for demanding environments
where pitting, crevice corrosion, or sulfide stress cracking are concerns.
2. F51 Flange Chemical Composition: Optimized Dual-Phase Structure
The corrosion resistance of Duplex 2205 stems from its balanced chemistry:
| Element | ASTM A182 F51 (%) | EN 1.4462 (%) | Role in Performance |
|---|---|---|---|
| Chromium (Cr) | 21.0 - 23.0 | 21.0 - 23.0 | Pitting/Corrosion Resistance |
| Nickel (Ni) | 4.5 - 6.5 | 4.5 - 6.5 | Austenite Stabilization |
| Molybdenum (Mo) | 2.5 - 3.5 | 2.5 - 3.5 | Chloride Resistance |
| Nitrogen (N) | 0.08 - 0.20 | 0.10 - 0.22 | Strength & Pitting Resistance |
| Manganese (Mn) | ≤ 2.00 | ≤ 2.00 | Sulfide Control |
| Carbon (C) | ≤ 0.030 | ≤ 0.030 | Prevents Sensitization |
| PREN | ≥ 34 | ≥ 35 | Pitting Resistance Equivalent |
3. Global Material Equivalents: Cross-Standard Compliance
F51 Duplex flanges meet international specifications:
| Standard | Grade | UNS | EN | Common Names |
|---|---|---|---|---|
| ASTM | F51 | S31803 | - | Duplex 2205 |
| ASME | SA-182 F51 | S31803 | - | ASME B16.5 Flange |
| EN | - | - | 1.4462 | Werkstoff 1.4462 |
| NACE | MR0175 Compliant | S31803 | 1.4462 | Sour Service Duplex |
4. Pressure-Temperature Ratings: ASME B16.5 Compliance
Maximum working pressure by class (PSI @ 100°F/38°C):
| Class | 150 | 300 | 600 | 900 | 1500 | 2500 |
|---|---|---|---|---|---|---|
| Pressure | 285 | 740 | 1480 | 2220 | 3705 | 6170 |
| Max Temp | 600°F | 600°F | 600°F | 600°F | 600°F | 600°F |
| Min Temp | -50°F | -50°F | -50°F | -50°F | -50°F | -50°F |
5. Key Advantages of F51 Duplex Flanges
- Corrosion Resistance: Withstands chlorides up to 40,000 ppm (vs. 316L’s 2,000 ppm limit)
- Mechanical Strength: 65 ksi min yield strength – 2x 316L stainless steel
- Cost Efficiency: 30-40% lower lifecycle cost vs. super austenitic grades
- Fabrication: Excellent weldability with ER2209 filler metal
- Certification: PED 2014/68/EU Category I, NACE MR0175/ISO 15156
6. Critical Application Fields
- Offshore Oil & Gas: Subsea manifolds, seawater cooling systems
- Chemical Processing: Sulfuric acid pickling, chloride-bearing streams
- Desalination Plants: RO high-pressure piping, brine heaters
- Pulp & Paper: Bleach plants, digesters
- Flue Gas Desulfurization (FGD): Scrubber inlet/outlet ducting
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