Material Data Sheet and Technical Overview
The stainless steel grade 1.4539, commonly known as Alloy 904L, AISI 904L, UNS N08904, or simply 904L stainless steel, is a superaustenitic stainless steel with enhanced corrosion resistance. The high molybdenum and copper content of 904L material offers excellent resistance to various organic and inorganic acids, stress corrosion cracking, and pitting, making it suitable for demanding environments, including seawater applications.
Standards and Identifications of Stainless Steel 1.4539
EN: 1.4539 DIN: X1NiCrMoCu25-20-5 AISI: 904L UNS: N08904 Alternative designations include 904L stainless steel, SS 904L, stainless 904L, and Alloy 904L.
Material Profile: Superaustenitic Stainless Steel 904L
1.4539 / 904L steel is a superaustenitic stainless steel that exhibits outstanding resistance to a wide range of aggressive environments. Notable properties include:- Superior resistance to stress corrosion cracking and pitting corrosion
- Excellent resistance to chloride and halide environments, including seawater
- Exceptional durability in sulfuric and phosphoric acid conditions
- Resistance to intergranular corrosion both in supplied condition and after welding
Typical Applications of 1.4539 Stainless Steel
904L duplex and superaustenitic stainless steel 1.4539 are widely used in industries requiring exceptional corrosion resistance, such as:- Apparatus engineering
- Chemical and petrochemical industry
- Pharmaceutical industry
- Offshore and onshore engineering
- Fertilizer production
- Shipbuilding
- Environmental technology (e.g., flue gas desulfurization)
- Pulp and paper industry
Alloy 904L (1.4539 904L) is especially suitable for harsh environments where high resistance to corrosion and superior mechanical properties are essential. Its robust chemical composition ensures long-term durability and reliability in challenging industrial conditions.
Chemical Composition of 1.4539 Material
(weight proportion in %)
| Value | Proportion % |
|---|---|
| Carbon (C) | min. 0% - max. 0.02% |
| Manganese (Mn) | min. 0% - max. 2.00% |
| Silicon (Si) | min. 0% - max. 0.70% |
| Phosphorus (P) | min. 0% - max. 0.030% |
| Sulfur (S) | min. 0% - max. 0.010% |
| Chromium (Cr) | 19.0 – 21.0% |
| Nickel (Ni) | 24.0 – 26.0% |
| Molybdenum (Mo) | 4.0 – 5.0% |
| Nitrogen (N) | min. 0% - max. 0.15% |
| Copper (Cu) | 1.2 – 2.0% |
Mechanical Properties at 20 °C
| Hardness (HB) | ≤ 230 |
| Yield strength (Rp₀.₂) | ≥ 230 N/mm² |
| Tensile strength (Rm) | 530 – 730 N/mm² |
| Elongation (A5,65) | ≥ 30% |
| Elastic modulus | 195 kN/mm² |
Physical Properties of 904L Stainless Steel
- Density: 8.0 kg/dm³
- Electrical resistance: 1.0 Ω·mm²/m
- Thermal conductivity: 12 W/m·K
- Specific heat capacity: 450 J/kg·K
- Magnetizability: low (practically non-magnetic)
Temperature Behavior and Heat Resistance
Stainless steel 904L is suitable for use from temperatures as low as -60°C up to 400°C. It is highly resistant to intergranular corrosion even after welding and maintains strength in both high and low-temperature environments.- Solution annealing: 1050 – 1150°C (cooling in water or air)
- Hot forming: 1200 – 900°C (cooling in air)
- Service temperature range: -60°C to 400°C
- Weldability: Good, though it requires duplex materials (such as 1.4462) or nickel alloys for welding consumables to prevent hot cracking. Post-weld heat treatment is typically unnecessary.
- Machinability: Moderate
- Cold forming: Suitable
- Cold heading: Generally not common
- Polishability: Good
- Forging: Suitable for open-die and drop forging processes
Assignment to current and older standards
- Designation according to DIN: X 1 Ni Cr Mo Cu N
- ASTM Grade: 904 L
- EN: 1.4539
- ASME: 904 L
- AFNOR: X1NiCrMoCu 25-20-5
- SIS: 2562
- UNS: N 08904
- SEW 400(91´): 1.4539
- Vd TÜV 421: 1.4539
Tables and rates
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