Super Duplex Steel Alloy 255 Fasteners Overview
Zeon Exports supplies Super Duplex Steel Alloy 255 (UNS S32550, Ferralium 255) fasteners – bolts, nuts and studs – a copper-bearing super duplex grade with a PREN above 40 and outstanding resistance to sulphuric, nitric and phosphoric acids for oil & gas and marine bolted joints.
Super Duplex Steel Alloy 255 Fasteners (Ferralium 255) secure bolted connections in the most demanding acidic and chloride process piping and equipment. Its 25% chromium, 5% nickel, 3.5% molybdenum composition with roughly 2% copper gives outstanding resistance to sulphuric, nitric and phosphoric acids, and copper additions provide a self-healing effect at pitting sites.
- PREN >40 with copper addition for self-healing pitting resistance
- Yield ≥550 MPa, tensile ≥760 MPa – very high strength
- EN 10204 3.1 certified, export-ready worldwide
Quick Specifications of Super Duplex Steel Alloy 255 Fasteners
Super Duplex Steel Alloy 255 Fasteners are produced to internationally recognized bolting specifications.
| Field | Detail |
|---|---|
| Material/Grade | Super Duplex Steel Alloy 255 (Ferralium 255) |
| UNS | S32550 |
| Werkstoff Number | 1.4507 |
| Standards | ASTM A276, ASTM A479 |
| Form | Bolts, Nuts, Studs |
| Finish | Passivated |
| Heat Treatment | Solution Annealed, water quenched |
| Certification | EN 10204 3.1 |
Equivalent Grades of Alloy 255
Alloy 255 (Ferralium 255) is recognized under several international designations below.
| UNS | Werkstoff Number | EN Steel Name | Common Trade Name | ASTM/ASME Standard |
|---|---|---|---|---|
| S32550 | 1.4507 | X2CrNiMoCuN25-6-3 | Ferralium 255 | ASTM A276/A479 |
Chemical Composition of Alloy 255
Composition per ASTM A276/A479 for UNS S32550; exact limits can vary slightly by specification and heat.
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 24.0 – 27.0 |
| Nickel (Ni) | 4.5 – 6.5 |
| Molybdenum (Mo) | 2.9 – 3.9 |
| Nitrogen (N) | 0.10 – 0.25 |
| Copper (Cu) | 1.5 – 2.5 |
| Carbon (C), max | 0.040 |
| Manganese (Mn), max | 1.50 |
| Silicon (Si), max | 1.00 |
| Phosphorus (P), max | 0.040 |
| Sulphur (S), max | 0.030 |
| Iron (Fe) | Balance |
Physical Properties of Super Duplex Steel Alloy 255
Physical properties for Ferralium 255, confirmed against manufacturer data.
| Property | Value |
|---|---|
| Density | 7.85 g/cm3 |
| Melting Range | Confirm against applicable datasheet |
| Magnetic Behaviour | Magnetic (ferrite phase present) |
Mechanical Properties of Super Duplex Steel Alloy 255 Fasteners
Minimum mechanical properties per ASTM A276/A479 for UNS S32550.
| Property | Minimum Value |
|---|---|
| Tensile Strength | 760 MPa |
| Yield Strength (0.2% offset) | 550 MPa |
| Elongation | 15% |
| Hardness | 302 HB max |
| Condition | Solution Annealed |
Corrosion Resistance of Super Duplex Steel Alloy 255
- With a PREN above 40, Super Duplex Steel Alloy 255 Fasteners significantly outperform standard duplex 2205 in aggressive acidic and chloride media.
- Pitting resistance: excellent resistance to chloride-induced pitting, with copper providing a self-healing effect at pit sites.
- Crevice resistance: strong performance under bolt heads, nuts and flange faces.
- Chloride SCC resistance: high resistance to chloride stress corrosion cracking even in hot chloride environments.
Heat Resistance of Super Duplex Steel Alloy 255
Alloy 255 fasteners are generally suited to moderate continuous service temperatures typical of super duplex grades; industry guidance commonly limits continuous use to roughly 300°C to avoid embrittlement risk. Always confirm exact service limits against the governing standard and application before specifying.
Key Properties of Super Duplex Steel Alloy 255 Fasteners
Beyond corrosion and heat performance, Ferralium 255 fasteners offer these additional properties.
- Very high strength with good ductility (15% minimum elongation)
- Good weldability with matching filler metal
- Outstanding resistance to sulphuric, nitric and phosphoric acids
- Good impact toughness maintained into cold service temperatures
Benefits of Super Duplex Steel Alloy 255 Fasteners
Choosing Ferralium 255 fasteners from Zeon Exports delivers measurable advantages for your project.
- Best-in-class resistance to acidic and chloride attack combined
- Full MTC 3.1 documentation for project QA/QC requirements
- Multiple sizes, threads and finishes to match exact project specs
- Reliable bulk supply with consistent ready stock
- Competitive export pricing for large industrial orders
- Fast dispatch to global project sites and ports
Related Products
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Request a Quote for Super Duplex Steel Alloy 255 Fasteners
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Call: +91 98205 33105
Email: info@zeonexports.com
Website: www.zeonexports.com
Address: A-7/9, Saboo Building, Ardeshir Dady Cross Lane, Cawasji Patel Tank Road, Mumbai – 400004
Frequently Asked Questions About Super Duplex Steel Alloy 255 Fasteners
Common questions about Super Duplex Steel Alloy 255 Fasteners, answered below.
Q1: What is Super Duplex Steel Alloy 255 (Ferralium 255)?
Ans. Ferralium 255 (UNS S32550) is a copper-bearing super duplex stainless steel with a PREN above 40.
Q2: Which fastener types are available in Alloy 255?
Ans. We supply bolts, nuts and studs to ASTM A276/A479 across standard thread sizes and lengths.
Q3: What standards do Alloy 255 fasteners meet?
Ans. Fasteners are manufactured to ASTM A276/A479, certified to EN 10204 3.1 mill test certificates.
Q4: How does Alloy 255 differ from Alloy 2507?
Ans. Alloy 255 adds roughly 2% copper for a self-healing pitting effect and strong acid resistance, versus 2507's copper-free composition.
Q5: What is the maximum service temperature?
Ans. Continuous service is generally limited to roughly 300°C; confirm exact limits against your design code.
Q6: Is Alloy 255 magnetic?
Ans. Yes, like other duplex grades, Alloy 255 is magnetic due to its ferrite phase content.
Q7: What certification is provided with orders?
Ans. Every order ships with EN 10204 3.1 mill test certificates confirming grade, heat and dimensions.
Q8: Does Zeon Exports supply custom sizes?
Ans. Yes, fasteners are available in custom thread sizes and lengths on request for bulk industrial orders.
