is 904L a stainless steel or nickel alloy?
Apr 24, 2026
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what is special about 904L stainless steel?
904L stainless steel belongs to the super-austenitic stainless steel family, distinguished by its exceptional corrosion resistance in harsh environments particularly those containing chlorides and reducing acids such as sulfuric acid. Its chemical composition features high levels of nickel (23–28%), chromium (19–23%), and molybdenum (4–5%), along with a significant addition of copper (1–2%) a characteristic not found in standard 300-series stainless steels.
Is 904L Stainless Steel Good?
904L stainless steel is an exceptional, high-performance super-austenitic stainless steel. Thanks to its high molybdenum, chromium, and nickel content, its corrosion resistance particularly in sulfuric acid and chloride-rich environments is far superior to that of 316L. Furthermore, it achieves an extremely high luster and excellent aesthetic appeal after processing, making it a common choice for high-end timepieces (such as Rolex) and chemical processing equipment. Its drawbacks include its high hardness which makes it difficult to machine and its relatively high cost.
What is 904L stainless steel equivalent to?
904L stainless steel (UNS N08904 / 1.4539) is a super austenitic grade, often called "23/28" stainless due to its 23-28% nickel content. Its primary equivalents include DIN 1.4539, AISI 904L, and UNS N08904. It offers superior corrosion resistance compared to 316L, particularly against hot sulfuric acid, seawater, and chloride-rich environments.
Chemical Composition (ASTM A240 / A276)
| Element | Content (%) |
| Chromium (Cr) | 19.0 – 23.0 |
| Nickel (Ni) | 23.0 – 28.0 |
| Molybdenum (Mo) | 4.0 – 5.0 |
| Copper (Cu) | 1.0 – 2.0 |
| Manganese (Mn) | ≤ 2.0 |
| Silicon (Si) | ≤ 1.0 |
| Carbon (C) | ≤ 0.020 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.035 |
Mechanical Properties (At Room Temperature)
| Property | Value (Metric) | Value (Imperial) |
| Tensile Strength (min) | 490 MPa | 71 ksi |
| Yield Strength (0.2% Offset, min) | 220 MPa | 31 ksi |
| Elongation (in 50mm, min) | 35% | 35% |
| Hardness (Rockwell B) | 70 – 90 HRB | 70 – 90 HRB |
| Hardness (Brinell, max) | 215 HBW | 215 HBW |
| Density | 7.95 g/cm³ | 0.287 lb/in³ |
904L VS. 316L :Corrosion Resistance Comparison (PREN)
The Pitting Resistance Equivalent Number (PREN) is calculated as: PREN = %Cr + 3.3 x %Mo + 16 x %N
| Grade | PREN Value | Chloride Environment Performance |
| 316L | ~24-26 | Moderate: Suitable for urban environments and mild chemicals. |
| 904L | ~34-36 | High: Suitable for seawater and severe acidic environments. |
| 2205 (Duplex) | ~35 | High: Comparable to 904L but with higher strength and less ductility. |
904L vs. 2205 Duplex Stainless Steel: The Differences
904L is a high-alloy austenitic stainless steel renowned for superior corrosion resistance in acidic environments (sulfuric/phosphoric) and excellent formability. 2205 Duplex is a mixed ferritic-austenitic steel offering roughly double the yield strength of 904L, better chloride stress corrosion cracking resistance, and greater cost-effectiveness, but lower formability and narrower temperature usage.
What are the differences between 904L and Alloy 926?
Alloy 926 (1.4529) is an enhanced, advanced version of Alloy 904L (1.4539), specifically designed to withstand more demanding chloride-containing environments. Compared to 904L, it offers superior corrosion resistance particularly against pitting and crevice corrosion achieved by increasing the molybdenum content to approximately 6.5% and boosting the nitrogen addition. Although both are high-performance austenitic stainless steels, Alloy 926 is classified as a "6-moly" grade stainless steel, endowing it with greater resilience in seawater and acidic environments.
where to buy 904L sheet?
GNEE supplies a wide range of 904L products that comply with international standards such as ASTM, ASME, and EN:
Round Bars & Rods:
Condition: Black bars, peeled bars, cold-drawn bars, centerless ground bars.
Precision: Available with high-precision tolerances in grades h8, h9, and h11.
Applications: Pump shafts, valve stems, fasteners, high-end watch cases.
Plates & Sheets:
Cold Rolled (2B/BA): Thickness 0.3mm – 6.0mm.
Hot Rolled (No.1): Thickness 3.0mm – 100mm.
Processing: Laser cutting to specific lengths, waterjet cutting, and custom shape cutting services available.
Pipes & Tubes:
Seamless: Suitable for high-pressure chemical pipelines.
Welded: Suitable for heat exchangers and low-pressure fluid conveyance.
Specifications: Ranging from instrumentation tubing to large-diameter industrial pipes.
Our Products
If you want to know more details and prices of the products, please contact us in time! sales@gneestainless.com
All products are accompanied by original Material Test Certificates (MTC) compliant with the EN 10204 3.1 standard, and we welcome on-site inspections by third-party agencies (such as SGS or TUV).
We maintain a ready stock of 904L round bars and plates, thereby eliminating the typical 2–3 month waiting period required for customers to place direct orders with steel mills; in-stock items can typically be dispatched within 3–7 days.
Given the specific characteristics of 904L stainless steel, we utilize extra-thick, fumigated wooden crates to ensure that the material remains free from scratches and salt-spray corrosion during maritime transport.
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