What is the difference between 1.4539 and 904L?
Aug 28, 2025
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When buyers search for stainless steel materials for highly corrosive environments, two designations often appear: 1.4539 and 904L. At first glance, they look like two different grades, but are they really? Let's break down the difference from a technical and purchasing perspective.
What Is 1.4539 Stainless Steel?
1.4539 stainless steel, also known as 904L, is a high-alloy austenitic stainless steel. Due to its high nickel, molybdenum, and copper contents, it offers excellent resistance to various corrosive environments, particularly sulfuric and phosphoric acids. It can be processed into a variety of practical product forms.
What Is 904L Stainless Steel?
904L is the ASTM/UNS (UNS N08904) designation for the same alloy. It has the same chemical composition and properties as EN 1.4539, designed for similar high-corrosion environments. It was originally developed by Outokumpu for acid-resistant applications and has since become a global standard.
What is the UNS number for 904L stainless steel?
UNS N08904, commonly known as 904L, is a low carbon high alloy austenitic stainless steel which is widely used in applications where the corrosion properties of AISI 316L and AISI 317L are not adequate.
1.4539 EN numeric designation according to EN 10088-1 (European standard)
904L Common trade name and UNS N08904 (ASTM/UNS system)
Chemical Composition (Typical Range)
| Element | 1.4539 (EN) / 904L (UNS N08904) |
|---|---|
| C (Carbon) | ≤ 0.02% |
| Cr (Chromium) | 19 – 23% |
| Ni (Nickel) | 23 – 28% |
| Mo (Molybdenum) | 4 – 5% |
| Cu (Copper) | 1 – 2% |
| N (Nitrogen) | ≤ 0.10% |
Mechanical Properties
| Property | 1.4539 / 904L |
|---|---|
| Tensile Strength | 490 – 710 MPa |
| Yield Strength (0.2%) | ≥ 220 MPa |
| Elongation | ≥ 35% |
| Hardness | ≤ 90 HRB |
What is the difference between 1.4529 and 904L?
Material 1.4529, also known as Alloy 926, is an austenitic special steel with a higher corrosion resistance than conventional chrome-nickel steel. Alloy 926 represents an enhancement to Alloy 904L (1.4539) stainless steel, with a raised molybdenum content and additional nitrogen.
Is 904L a duplex steel?
Duplex steel (DP steel) is a steel composed of a two-phase structure: martensite, austenite, or bainite, within a ferrite matrix. However, 904L is not a duplex steel, but rather a high-alloy austenitic stainless steel. While not a duplex steel, 904L stainless steel's excellent corrosion resistance, high strength, and good mechanical properties make it an excellent alternative in many applications.
who choose us?
GNEE Stainless is an independent stockist and processor of 1.4539 904L stainless steel. With our extensive inventory and exceptional processing capabilities, we are able to meet most project requirements, whether for stock or custom production. We offer: stock-sized plate and sheet, stock-length round bar, cut-to-length plate and sheet, cut-to-length round bar, cold forming of plate, sheet, and round bar, and any other necessary processing services. For any questions, please Email: sales@gneestainless.com
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