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| UNS Number | S32550 |
|---|---|
| ASTM Standard | ASTM A182 / A479 |
| Tensile Strength | 760 MPa min |
| Yield Strength | 550 MPa min |
| Density | 7.81 g/cm³ |
| Max Service Temp | 300°C |
| Element | Composition (%) |
|---|---|
| Cr | 24.0–27.0 |
| Ni | 4.5–6.5 |
| Mo | 2.9–3.9 |
| Cu | 1.5–2.5 |
| N | 0.10–0.25 |
| Mn | ≤1.5 |
| C | ≤0.04 |
| Fe | bal |
Ferralium 255 fasteners derive their exceptional performance from a carefully balanced composition of chromium, nickel, molybdenum, copper and nitrogen. Chromium provides the foundation for passive film formation, while molybdenum and nitrogen work synergistically to enhance pitting and crevice corrosion resistance in aggressive chloride environments. Copper additions further improve resistance to acidic media, and nickel stabilises the duplex austenitic-ferritic microstructure, ensuring optimal mechanical strength and toughness balance across a wide temperature range.
This engineered composition delivers superior corrosion resistance, high mechanical strength and excellent resistance to stress corrosion cracking, making Ferralium 255 fasteners ideal for offshore, marine, chemical processing and desalination applications. Their high yield strength allows for reduced fastener sizing without compromising joint integrity, while their resistance to hydrogen embrittlement and pitting ensures long-term reliability in demanding, corrosive service conditions where standard stainless steel fasteners would fail prematurely.
Specifications
Ferralium 255 Fasteners combine high-strength mechanical properties with precise dimensional specifications for demanding corrosion-resistant applications. Their technical data typically covers diameter, length, threading, and tolerances, while performance is defined by strength, hardness, and toughness characteristics suited to reliable service in aggressive environments.
| Property | Value |
|---|---|
| Tensile Strength | 760 MPa min |
| Yield Strength (0.2%) | 550 MPa min |
| Elongation | 15% min |
| Hardness | 28-32 HRC |
| Modulus of Elasticity | 200 GPa |
| Thermal Expansion (20-100°C) | 13.5 x10⁻⁶/°C |
| Thermal Conductivity | 14 W/m·K |
| Density | 7.81 g/cm³ |
| Melting Range | 1350-1400°C |
| Max Service Temperature | 300°C |
| Standard | Details |
|---|---|
| Bolt Standard | ASME B18.2.1 / DIN 931 |
| Stud Bolt Standard | ASME B16.5 / API 6A |
| Nut Standard | ASME B18.2.2 / DIN 934 |
| Washer Standard | ASME B18.22.1 |
| Thread Form | UNC, UNF, Metric Coarse/Fine |
| Diameter Range | M6 to M100 / 1/4" to 4" |
| Length Range | 10mm to 500mm |
| Product Forms | Bolts, Studs, Nuts, Screws, Washers |
| Custom Sizes | Available on request |
| Inspection Standards | EN 10204 3.1 / NACE MR0175 |
Applications
