Exotic Alloys SS 904L Flanges Overview
Zeon Exports supplies Exotic Alloys SS 904L (UNS N08904) flanges, a low-carbon super austenitic stainless steel with copper addition for outstanding resistance to sulfuric acid and chloride environments in chemical and oil & gas process piping.
Exotic Alloys SS 904L Flanges connect and seal sulfuric acid, seawater and other aggressive chloride-bearing process piping in chemical and oil & gas systems. Its high nickel and molybdenum content, roughly double that of 316L, combined with copper addition gives outstanding resistance to sulfuric acid, pitting and stress corrosion cracking.
- Copper addition gives strong sulfuric acid resistance across concentrations
- Tensile ≥490 MPa, yield ≥220 MPa in the annealed condition
- EN 10204 3.1 certified, export-ready worldwide
Quick Specifications of Exotic Alloys SS 904L Flanges
Exotic Alloys SS 904L Flanges are produced to internationally recognized specifications.
| Field | Detail |
|---|---|
| Material/Grade | Exotic Alloys SS 904L |
| UNS | N08904 |
| DIN/Werkstoff Number | 1.4539 |
| Standards | ASTM A182 Gr. F904L |
| 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 SS 904L
SS 904L is recognized under several international designations below.
| UNS | DIN/Werkstoff Number | Common Trade Name | ASTM/ASME Standard |
|---|---|---|---|
| N08904 | 1.4539 | 904L | ASTM A182 Gr. F904L |
Chemical Composition of SS 904L
Composition per ASTM A182 for UNS N08904; exact limits can vary slightly by specification and heat.
| Element | Composition (%) |
|---|---|
| Chromium (Cr) | 19.0 – 23.0 |
| Nickel (Ni) | 23.0 – 28.0 |
| Molybdenum (Mo) | 4.0 – 5.0 |
| Copper (Cu) | 1.0 – 2.0 |
| Nitrogen (N), max | 0.10 |
| Carbon (C), max | 0.020 |
| Manganese (Mn), max | 2.00 |
| Silicon (Si), max | 1.00 |
| Phosphorus (P), max | 0.045 |
| Sulphur (S), max | 0.035 |
| Iron (Fe) | Balance |
Physical Properties of Exotic Alloys SS 904L
Typical physical properties for 904L; 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 (annealed) |
Mechanical Properties of Exotic Alloys SS 904L Flanges
Minimum mechanical properties for annealed UNS N08904 per ASTM A182.
| Property | Minimum Value |
|---|---|
| Tensile Strength | 490 MPa (71 ksi) |
| Yield Strength (0.2% offset) | 220 MPa (31 ksi) |
| Elongation | 35% |
| Hardness | 90 HB max |
| Condition | Solution Annealed |
Corrosion Resistance of Exotic Alloys SS 904L
- Exotic Alloys SS 904L Flanges were developed for medium-concentration sulfuric acid and chloride-bearing environments.
- Acid resistance: copper addition makes it useful across all concentrations of sulfuric acid.
- Pitting and crevice resistance: high molybdenum and nickel give strong resistance to chloride pitting and crevice attack.
- Chloride SCC resistance: high nickel content resists chloride stress corrosion cracking that limits standard austenitic grades.
Heat Resistance of Exotic Alloys SS 904L
Exotic Alloys SS 904L flanges are non-magnetic in the annealed condition and offer good toughness at cryogenic temperatures, but are generally selected for moderate-temperature aqueous and chemical service. Confirm exact service limits against the governing standard and application before specifying.
Key Properties of Exotic Alloys SS 904L Flanges
Beyond corrosion and heat performance, 904L flanges offer these additional properties.
- Good toughness at cryogenic temperatures
- Excellent formability and weldability
- Greater resistance to ferrite and sigma phase precipitation than 316L
- Widely used in chemical, oil & gas and pharmaceutical industries
Benefits of Exotic Alloys SS 904L Flanges
Choosing 904L flanges from Zeon Exports delivers measurable advantages for your project.
- Strong sulfuric acid and chloride resistance at moderate 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 SS 904L Flanges
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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 Exotic Alloys SS 904L Flanges
Common questions about Exotic Alloys SS 904L Flanges, answered below.
Q1: What is SS 904L?
Ans. SS 904L (UNS N08904) is a low-carbon super austenitic stainless steel with copper addition for sulfuric acid resistance.
Q2: What flange types are available in 904L?
Ans. We supply Weld Neck, Slip-On, Blind and other flange types manufactured to ASTM A182 F904L.
Q3: What standards do 904L flanges meet?
Ans. Flanges are manufactured to ASTM A182 F904L, certified to EN 10204 3.1 mill test certificates.
Q4: Is 904L magnetic?
Ans. 904L is essentially non-magnetic in the annealed condition, being a fully austenitic stainless steel.
Q5: How does 904L compare to 316L?
Ans. 904L has roughly double the nickel and molybdenum of 316L, plus copper, giving much stronger sulfuric acid and chloride resistance.
Q6: Is 904L suitable for seawater service?
Ans. Yes, 904L has high resistance to pitting and crevice corrosion in chloride solutions including seawater.
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.




