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UNS S32760 Super Duplex Stainless Steel
Super Duplex UNS S32760 / F55 / 1.4501 is among the most common super duplex grade in the market. UNS S32760 is duplex stainless steel specially designed for service in aggressive chloride-containing environments and has additions of W and Cu compared to UNS S32750. It has very good resistance to localized corrosion and stress corrosion cracking in combination with high mechanical strength.
Stainless steel grade F55 has excellent corrosion resistance to a wide range of areas, especially resistance to pitting and crevice corrosion in seawater and other chloride-containing environments, with critical pitting temperature that is more than 50°C (122°F). This material is known to also have high strength and an extended lifecycle. It is 10% lighter than grade 316 steel, ideal for sub-zero service, and more cost-effective than nickel alloys. Stainless steel grade F55 can be easily machined and welded.
Related Specifications
1.4501 BS EN 10088-3 ASTM A182 F55 X2CrNiMoCuWN25-7-4
Applications
Analysis
Corrosion Resistance
Welding
Typical Physical Properties
Heat Treatment
Minimum Mechanical Properties*
Applications
Grade F55 steel is widely used in the following applications:
Pumps
Valves
Chokes
Bolting
Pipework/flanges
Connectors and manifolds
Oil and gas industry
Equipment in defence, chemical and marine industries
Analysis
| Carbon | 0.03% max | Chromium | 24.00-26.00% |
| Manganese | 1.00% max | Nickel | 6.00-8.00% |
| Silicon | 1.00% max | Molybdenum | 3.00-4.00% |
| Phosphorous | 0.035% max | Copper | 0.50-1.00% |
| Sulphur | 0.015% max | Nitrogen | 0.20-0.30% |
| Tungsten | 0.50-1.00% |
Corrosion Resistance
The high chromium and molybdenum content of Super Duplex makes it extremely resistant to uniform corrosion by organic acids like formic and acetic acid. Super Duplex also provides excellent resistance to inorganic acids, especially those containing chlorides.
The pitting resistance equivalent of Super Duplex, calculated by PREN = Cr + 3.3Mo + 16N, will exceed 40 in most material forms.
Welding
Welding procedures are similar to those applied for conventional duplex stainless steel grades. Electric arc welding processes is suitable for UNS S32760 super duplex stainless steel, though oxyacetylene welding is not recommended due to the possibility of carbon pick up in the weld area. We recommend you contact your welding consumables supplier who should provide you full assistance and information of welding UNS S32760 super duplex.
Typical Physical Properties
| Temp ºC | Density Kg/m³ | Mean Coefficient of Thermal Expansion at 20-100°C | Thermal Conductivity W.m-¹.°C | Modulus of Elasticity GPa | Specific Thermal Capacity J.Kg-¹.K-¹ |
|---|---|---|---|---|---|
| 20 | 7.80 | 13.0×10-6 | 15 | 200 | 500 |
Heat Treatment
UNS S2760 1.4501 F55 cannot be hardened by conventional heat treatments, though this is a work hardening steel. Super duplex can be solution annealed at 1110-1140ºC, water quench.
Minimum Mechanical Properties*
| Tensile UTS N/mm² | 0.2% Proof Stress N/mm² min | Elongation % min | Hardness HB max | Impact J |
|---|---|---|---|---|
| 730-930 | 530 | 25 | 290 | 100 |
*Minimum Mechanical Properties at room temperature (160mm dia max – solution treated)
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