Stainless steel 904L – properties, applications and technical data
AISI 904L (UNS N08904 / EN 1.4539) is a highly alloyed austenitic stainless steel with a very low carbon content and very good corrosion resistance in aggressive environments.
The material is specially developed to withstand strong acids, chloride-containing environments and process environments where conventional stainless steels do not provide sufficient corrosion resistance.
The alloy is often used in the chemical process industry, petrochemical plants, desalination systems and other applications where high corrosion resistance and long service life are crucial.
Properties of 904L
904L is a fully austenitic stainless steel with a high content of nickel, chromium, molybdenum and copper, which provides very good resistance to both general corrosion and localized corrosion.
The material also has improved resistance to crevice corrosion and pitting in chloride-containing environments compared to many conventional stainless steels.
- Type: high-alloy austenitic stainless steel
- Alloy: Fe-Cr-Ni-Mo-Cu
- Structure: fully austenitic stainless steel
- Designations: 904L, Alloy 904L, UNS N08904, EN 1.4539, DIN 1.4539, AISI 904L
- Typical composition: Cr ~20%, Ni ~25%, Mo ~4.5%, Cu ~1.5 %
Advantages
- Very high corrosion resistance in aggressive chemical environments
- Very good resistance to pitting and crevice corrosion
- Good resistance to sulfuric acid and other acids
- Low carbon content reduces the risk of intercrystalline corrosion
- Good weldability and formability
Limitations
- Higher material cost than standard austenitic stainless steels
- Lower mechanical strength than some duplex steels
- Can be replaced by duplex alloys in certain designs
Common product forms for 904L
- Round bar
- Sheet and plate
- Tubes and tubes
- Forgings
- Special dimensions according to drawing
Typical components manufactured in 904L
- Process equipment in the chemical industry
- Heat exchangers
- Desalting systems
- Flue gas purification equipment
- Tanks and process vessels
Corrosion resistance
904L offers very good resistance to general corrosion as well as to localized corrosion such as pitting and crevice corrosion.
The alloy is often used in environments where acids, chlorides or seawater is present and where standard austenitic steels are not sufficient.
Environments where 904L performs well
- Chemical and petrochemical process industries
- Pulp and paper industries
- Flue gas cleaning systems
- Desalination and seawater environments
- Food and pharmaceutical production
Environments to avoid
- Applications where higher mechanical strength is required
- Environments where duplex steels may be more cost-effective
Technical data (annealed state)
| Yield strength (0.2%) |
~220 MPa |
| Tensile strength |
~490–690 MPa |
| Elongation |
~35 % |
| Density |
~8.0 g/cm³ |
| Modulus of elasticity |
~195 GPa |
| PREN value |
~35 |
| Weldability |
Good – can be welded using standard austenitic stainless steel methods |
With a global network of suppliers, we can offer 904L in technical dimensions for corrosion-demanding applications.
Contact us for technical advice or a quote.
Supplier of 904L with certified quality
HARALD PIHL is one of Europe's largest suppliers of special alloys and advanced stainless steels such as 904L.
With over 100 years of experience in the metal industry, we deliver materials with full traceability and certification according to EN 10204 3.1 / 3.2 as well as relevant ASTM and ISO standards.
Cutting, testing and quality assurance are carried out in-house to ensure the right tolerances and fast global delivery for technically demanding projects.
- Europe's largest stock of nickel and titanium alloys
- Special alloys from stock
- ASTM / ISO standards
- Top quality for safety-critical applications
- Fast global delivery
- Full material certification (EN 10204 3.1 / 3.2)
- Over 100 years in the metal industry
- Nickel and titanium experts
