254 SMO – Properties, Applications and Technical Data
254 SMO is a high-alloy austenitic stainless steel developed for extreme corrosion resistance in chloride-rich and aggressive environments. The material is specifically designed to resist pitting, crevice corrosion and stress corrosion cracking in seawater and chemical process environments.
Due to its high chromium, molybdenum and nitrogen content, 254 SMO offers significantly better corrosion resistance than standard grades such as 316L and duplex 2205.
Properties of 254 SMO
254 SMO (UNS S31254 / Werkstoffnr 1.4547) is a super-austenitic alloy with a very high PREN value, which provides excellent resistance to localized corrosion in chloride-containing environments.
The material combines high strength with very good toughness and is suitable for use in marine applications, offshore, desalination plants and the chemical process industry.
Type: Super-austenitic stainless steel
Alloy: Fe-Cr-Ni-Mo-N (254 SMO)
Structure: Austenitic
Designations: 254 SMO, UNS S31254, Werkstoffnr 1.4547
Standards: ASTM A240, ASTM A276, ASTM A312, EN 10088
Advantages
- Exceptional resistance to pitting and crevice corrosion
- Very good resistance in seawater and chloride environments
- High strength compared to 316L
- Good weldability
- Suitable for high pressures and aggressive chemical processes
Limitations
- Higher material cost than standard austenitic steels
- May require controlled welding procedure for optimal performance
- Not intended for very high temperatures above design limit
Typical applications
Offshore & Marine
Piping systems, heat exchangers and components in seawater environments.
Desalination
High-pressure pipes and systems in desalination plants.
Chemical process industry
Reactors, tanks and heat exchangers in chloride-rich environments.
Environmental technology
Flue gas cleaning and process equipment with high corrosion requirements.
Corrosion resistance
254 SMO offers superior resistance to chlorides and localized corrosion compared to conventional stainless steels. The high molybdenum and nitrogen content provides very good protection against pitting and crevice corrosion even in warm marine environments.
Environments where 254 SMO works well
- Seawater and marine environments
- Chloride-rich process environments
- Desalting systems
- High-pressure applications with corrosion risk
Environments to avoid
- Very high temperatures above the alloy's design limit
- Applications where simpler materials provide sufficient performance
Technical data (annealed condition)
| Yield strength (0.2%) |
~300 MPa |
| Tensile strength |
~650–750 MPa |
| Elongation at break |
~35–50% |
| Density |
~8.0 g/cm³ |
| Modulus of elasticity |
~195 GPa |
| PREN value |
>42 |
| Weldability |
Good - correct filler metal recommended |
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Contact us if you need technical advice or a quote - we will help you find the right material for your application.
Buy 254 SMO from HARALD PIHL - your specialist in high-alloy stainless materials with global delivery.
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- ISO 9001 and AS9120 certified quality management
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