UNS N08904 vs 1.4539: What’s the Difference?
May 22, 2025
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When sourcing or specifying 904L stainless steel, you may encounter two commonly used designations: UNS N08904 and EN 1.4539. While they both refer to the same material grade, understanding their differences in context, region, and usage is critical-especially for international procurement and compliance.
904L Stainless Steel Supplier - GNEE
UNS N08904 and EN 1.4539 are technically equivalent. They both refer to 904L stainless steel, a high-alloy austenitic grade known for its excellent resistance to strong acids and chloride-rich environments. The difference lies in the standardization system and regional usage.
UNS N08904 Standards
|
Designation |
Standard System | Region | Typical Usage |
|---|---|---|---|
| UNS N08904 | Unified Numbering System (UNS) | USA / Global | Used in ASTM/ASME specifications, e.g. ASTM B625 |
| EN 1.4539 | EN 10088-1 (EN Standard) | Europe | Used in DIN, EN, and ISO certifications |
In short:
N08904 is used in American and global mill certificates (e.g. ASTM, ASME).
1.4539 is used in European standard documents, data sheets, and CE-certified products.
UNS N08904 stainless steel Chemical Composition
| Element | UNS N08904 / EN 1.4539 |
|---|---|
| Chromium (Cr) | 19.0 – 23.0% |
| Nickel (Ni) | 23.0 – 28.0% |
| Molybdenum (Mo) | 4.0 – 5.0% |
| Copper (Cu) | 1.0 – 2.0% |
| Carbon (C) | ≤ 0.02% |
UNS N08904 vs. 1.4539: Mechanical Properties Comparison
| Property | UNS N08904 (ASTM) | EN 1.4539 (EN 10088) | Notes |
|---|---|---|---|
| Tensile Strength | ≥ 490 MPa | ≥ 500 MPa | ASTM B625 requirement is slightly lower than EN |
| 0.2% Yield Strength | ≥ 220 MPa | ≥ 220 MPa | Both standards are identical in this aspect |
| Elongation (L=5d or A50) | ≥ 35% | ≥ 35% | Typical for hot-rolled plate or sheet |
| Brinell Hardness (HBW) | ≤ 220 | ≤ 220 | Usually delivered in solution-annealed condition |
| Charpy Impact (V-notch) | - | Required for some EN projects (> 60 J) | Not mandatory in ASTM; optional in EN based on project need |
| Heat Treatment Condition | Solution Annealed | Solution Annealed | Annealing range: 1090–1175°C followed by rapid cooling |
Conclusion
UNS N08904 is the ASTM/ASME Unified Numbering System designation, commonly applied in standards like ASTM B625 (plate) and ASTM B673 (pipe).
EN 1.4539, also known as X1NiCrMoCu25-20-5, is the European material number specified in EN 10088.
Mechanical properties may vary slightly depending on product form (sheet, pipe, bar), delivery condition, and test method.
Ensure full compliance-ask for 1.4539 / N08904 material certificates now!
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