A182 Gr. F51 and F60 are duplex stainless steel forging grades offering high strength, excellent corrosion resistance, and superior performance in offshore, chemical, and high-pressure systems. Learn their properties, equivalent materials, and applications.
What Is A182 Gr. F51 / F60?
A182 Gr. F51 and F60 are duplex stainless steel forging grades under the ASTM A182 standard, mainly used for flanges, fittings, valves, and pressure-containing components that operate under high pressure, corrosion, and elevated temperature.
Both grades belong to the duplex stainless steel family, combining austenitic + ferritic structures, offering high strength, excellent chloride stress corrosion cracking resistance, and superior pitting/crevice corrosion resistance.
- F51 ≈ Duplex 2205 (UNS S31803)
- F60 ≈ Super Duplex (UNS S32205 / S32760 depending on enhancement)
F60 typically offers slightly better pitting resistance, higher PREN value, and improved toughness.
A182 Gr. F51 / F60 — Equivalent Materials
| Standard | Equivalent to F51 / F60 |
| UNS | S31803 (F51), S32205 (F60) |
| EN / DIN | 1.4462 |
| ISO | X2CrNiMoN22-5-3 |
| WNR | 1.4462 |
| Other Common Names | Duplex 2205, 22Cr Duplex |
Chemical Composition
| Element | UNS | C | Mn | P | S | Si | Ni | Cr | Mo | N |
| F51 | S31803 | ≤ 0.03 | ≤ 2.0 | ≤ 0.03 | ≤ 0.02 | ≤ 1.0 | 4.5–6.5 | 21.0–23.0 | 2.5–3.5 | 0.08–0.20 |
| F60 | S32205 | ≤ 0.03 | ≤ 2.0 | ≤ 0.03 | ≤ 0.02 | ≤ 1.0 | 4.5–6.5 | 21.0–23.0 | 3.0–3.5 | 0.14–0.20 |
Note: UNS S32205 is the improved version of the earlier grade S31803 for Duplex 2205 stainless steel. By increasing the nitrogen content, S32205 achieves higher resistance to pitting and crevice corrosion, resulting in a higher PREN value. While S31803 typically has a PREN of 32–35, S32205 generally reaches 34–38, offering more stable and reliable performance. Because of these enhanced corrosion-resistant properties, most modern steel mills now primarily produce Duplex 2205 to the S32205 composition. In summary, S31803 represents the older standard specification, whereas S32205 was introduced later to meet more stringent corrosion-resistance requirements with a tighter and safer chemical composition range.
Mechanical Properties (Forged Condition)
| Grade Symbol | Tensile Strength, min. | Yield Strength, min. | Elongation min. % | Reduction of Area min. % | Brinell Hardness HBW |
| F51 | 90 ksi (620 MPa) | 65 ksi (450 MPa) | 25 | 45 | … |
| F60 | 95 ksi (655 MPa) | 65 ksi (450 MPa) | 25 | 45 | … |
Applications of A182 Gr. F51 / F60
A182 F51 (S31803) — Standard Duplex Grade
Suitable for:
- Offshore platforms and subsea piping
- Chemical processing lines
- Desalination equipment
- Pressure vessels and heat exchangers
- Pipelines with moderate chloride concentration
- Pulp & Paper industry
- Structural components requiring high strength
Feature: Balanced corrosion resistance + high strength.
A182 F60 (S32205) — Enhanced Duplex Grade
Used in more demanding conditions:
- High chloride seawater systems
- Power plant condensers
- High-pressure offshore piping
- Marine engineering
- Heat exchangers exposed to brine
- Chemical injection lines
- Oil & gas high-pressure manifolds
Feature: Higher PREN = Better pitting resistance and improved mechanical strength.
Conclusion
A182 Gr. F51 (S31803) and F60 (S32205) represent two of the most reliable duplex stainless steel forging grades used today. Their superior strength, excellent resistance to chloride-induced corrosion, and stable performance in high-pressure and offshore environments make them ideal for manufacturing flanges, fittings, valves, and critical piping components.
Whether the application involves seawater, chemical processing, or oil & gas operations, F51 and F60 provide the durability and efficiency needed for long-term service.
