Exotic Alloys Alloy 254 Flanges Overview
Zeon Exports supplies Exotic Alloy 254 (254 SMO, UNS S31254) flanges, a super austenitic 6% molybdenum stainless steel with a PREN of 42-44, developed for seawater and other aggressive chloride-bearing process piping.
Exotic Alloy 254 (254 SMO) Flanges connect and seal seawater and other aggressive chloride-bearing process piping in offshore, desalination and pulp mill bleach systems. Its 20% chromium, 18% nickel and 6% molybdenum composition with added nitrogen gives a PREN of 42-44, providing performance approaching nickel-based alloys while retaining the fabricability of stainless steel.
- PREN 42–44, roughly double the pitting resistance of 316L
- Tensile ≥650 MPa, yield ≥300 MPa in the annealed condition
- EN 10204 3.1 certified, export-ready worldwide
Quick Specifications of Exotic Alloys Alloy 254 Flanges
Exotic Alloy 254 (254 SMO) Flanges are produced to internationally recognized specifications.
| Field | Detail |
|---|---|
| Material/Grade | Exotic Alloy 254 (254 SMO) |
| UNS | S31254 |
| DIN/Werkstoff Number | 1.4547 |
| Standards | ASTM A182 Gr. F44 |
| Form | Weld Neck, Slip-On, Blind, Socket Weld |
| Finish | As specified (confirm on order) |
| Heat Treatment | Solution Annealed |
| Certification | EN 10204 3.1 |
Equivalent Grades of Alloy 254
Alloy 254 (254 SMO) is recognized under several international designations below.
| UNS | DIN/Werkstoff Number | Common Trade Name | ASTM/ASME Standard |
|---|---|---|---|
| S31254 | 1.4547 | 254 SMO / 6Mo / F44 | ASTM A182 Gr. F44 |
Chemical Composition of Alloy 254
Composition per ASTM A182 for UNS S31254; exact limits can vary slightly by specification and heat.
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 19.5 – 20.5 |
| Nickel (Ni) | 17.5 – 18.5 |
| Molybdenum (Mo) | 6.0 – 6.5 |
| Nitrogen (N) | 0.18 – 0.22 |
| Copper (Cu) | 0.50 – 1.00 |
| Carbon (C), max | 0.020 |
| Manganese (Mn), max | 1.00 |
| Silicon (Si), max | 0.80 |
| Phosphorus (P), max | 0.030 |
| Sulphur (S), max | 0.010 |
| Iron (Fe) | Balance |
Physical Properties of Exotic Alloy 254 (254 SMO)
Typical physical properties for 254 SMO; confirm exact heat-specific figures against the mill test certificate.
| Property | Value |
|---|---|
| Density | ~8.0 g/cm3 (typical) |
| Melting Range | ~1320 – 1390°C (typical) |
| Magnetic Behaviour | Essentially non-magnetic |
Mechanical Properties of Exotic Alloys Alloy 254 Flanges
Minimum mechanical properties for annealed UNS S31254 per ASTM A182.
| Property | Minimum Value |
|---|---|
| Tensile Strength | 650 MPa (95 ksi) |
| Yield Strength (0.2% offset) | 300 MPa (44 ksi) |
| Elongation | 35% |
| Condition | Solution Annealed |
Corrosion Resistance of Exotic Alloy 254 (254 SMO)
- Exotic Alloy 254 Flanges were developed specifically for seawater and other aggressive chloride environments.
- Pitting resistance: excellent resistance to chloride-induced pitting, roughly double that of 316L.
- Crevice resistance: high resistance to crevice corrosion in seawater, confirmed by ASTM G48 testing.
- Chloride SCC resistance: excellent resistance to chloride stress corrosion cracking, unlike standard austenitic grades.
Heat Resistance of Exotic Alloy 254 (254 SMO)
Exotic Alloy 254 flanges retain excellent ductility and impact strength at both ambient and sub-zero temperatures; they are generally selected for moderate-temperature aqueous service rather than high-temperature structural applications. Confirm exact service limits against the governing standard and application before specifying.
Key Properties of Exotic Alloys Alloy 254 Flanges
Beyond corrosion and heat performance, 254 SMO flanges offer these additional properties.
- Strength roughly twice that of standard 300-series stainless steel
- Excellent weldability without preheating required
- Low carbon content minimizes carbide precipitation risk
- Good ductility and impact strength at sub-zero temperatures
Benefits of Exotic Alloys Alloy 254 Flanges
Choosing 254 SMO flanges from Zeon Exports delivers measurable advantages for your project.
- Nickel-alloy-level corrosion resistance at a lower cost
- Full MTC 3.1 documentation for project QA/QC requirements
- Multiple flange types and pressure classes to match 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 Exotic Alloys Alloy 254 Flanges
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Call: +91 98205 33105
Email: info@zeonexports.com
Website: www.zeonexports.com
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Frequently Asked Questions About Exotic Alloys Alloy 254 Flanges
Common questions about Exotic Alloy 254 (254 SMO) Flanges, answered below.
Q1: What is Exotic Alloy 254 (254 SMO)?
Ans. 254 SMO (UNS S31254) is a super austenitic 6% molybdenum stainless steel with a PREN of 42-44.
Q2: What flange types are available in 254 SMO?
Ans. We supply Weld Neck, Slip-On, Blind and other flange types manufactured to ASTM A182 F44.
Q3: What standards do 254 SMO flanges meet?
Ans. Flanges are manufactured to ASTM A182 F44, certified to EN 10204 3.1 mill test certificates.
Q4: Is 254 SMO magnetic?
Ans. 254 SMO is essentially non-magnetic, being a fully austenitic stainless steel.
Q5: How does 254 SMO compare to 904L?
Ans. 254 SMO has higher molybdenum and nitrogen, giving a PREN of 42-44 versus 904L's PREN of around 34, for superior chloride pitting resistance.
Q6: Is 254 SMO suitable for seawater service?
Ans. Yes, 254 SMO was specifically developed for seawater and other aggressive chloride-bearing environments.
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 flange sizes?
Ans. Yes, flanges are available in custom sizes and pressure classes on request for bulk industrial orders.
