What Is A182 F53?
ASTM A182 Grade F53 is a forged super duplex stainless steel (UNS S32750 / 2507) for flanges, fittings, and valve parts in the most demanding chloride and sour gas environments. With a PREN above 40, F53 resists pitting in warm seawater and high-chloride brines where standard duplex F51 (2205) falls short.
| Property | Value |
|---|---|
| Specification | ASTM A182 / ASME SA-182 |
| Grade | F53 |
| UNS | S32750 |
| Common name | Super Duplex 2507 |
| Carbon | 0.030% max |
| Chromium | 24.0-26.0% |
| Nickel | 6.0-8.0% |
| Molybdenum | 3.0-5.0% |
| Nitrogen | 0.24-0.32% |
| Manganese | 1.20% max |
| Tensile strength (min) | 795 MPa (116 ksi) |
| Yield strength (min) | 550 MPa (80 ksi) |
| Elongation (min) | 15% |
| Hardness | 310 HBW max (32 HRC) |
| PREN (typical) | 41-43 |
| Ferrite | 40-60% |
| Heat treatment | Solution anneal 1025-1125°C, water quench |
| Max service temp | 315°C (600°F) |
| Cast equivalent | A995 Grade 5A |
F53 vs F51: When to Upgrade
| Property | F51 (Duplex 2205) | F53 (Super Duplex 2507) |
|---|---|---|
| PREN | 34-36 | 41-43 |
| Critical pitting temp | 35-45°C | 55-70°C |
| Yield strength (min) | 450 MPa (65 ksi) | 550 MPa (80 ksi) |
| Chloride SCC limit | ~100°C | ~130°C |
| Seawater service | Ambient temp only | Up to ~50°C |
| Relative cost | Baseline | +30-50% |
Specify F53 when the process fluid contains chlorides above 40°C, when sour gas conditions per NACE MR0175 require PREN above 40, or when subsea valve bodies and wellhead components face warm produced water with high salinity.
Applications
- Subsea production: wellhead flanges, manifold fittings, tree valve components
- Offshore HP/HT wells: tubing hanger flanges and production piping connections
- Seawater injection: high-pressure pump discharge flanges and piping fittings
- Sour gas processing: inlet separator flanges and slug catcher connections
- Chemical plants: hot chloride brine, ferric chloride, and concentrated seawater systems
F53 pairs with A995 5A cast valve bodies, A790 S32750 seamless pipe, and A815 S32750 buttweld fittings.
Testing and Quality
F53 forgings require solution annealing (1025-1125°C), rapid water quench, and ferrite verification (40-60%). Corrosion testing per ASTM A923 Method C (ferric chloride at 50°C) is standard. Impact testing at -46°C is commonly specified. Mill test certificates per EN 10204 3.1 or 3.2 report chemistry, mechanicals, ferrite content, and corrosion results. NDT includes ultrasonic examination of all forgings and liquid penetrant for surface defects. Hydrostatic testing follows ASME B16.5 or B16.47 for flanges, or the applicable valve standard.
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