254 SMO stainless steel is the super austenitic stainless steel.
Due to the high molybdenum content, it has extremely high resistance to pitting corrosion and crevice corrosion.
This grade of stainless steel is also known as UNS S31254.
This grade of stainless steel was developed and designed for containing halide application such as seawater.
254 SMO® is a registered trademark of Outokumpu OYJ.
History of 254 SMO Stainless Steel
The 254 SMO (UNS S31254) is a stainless steel that contains higher quantities of chromium, nickel, molybdenum and nitrogen than common stainless steels, such as 316, 316L and 304L.
Grade 254 SMO was developed twenty years ago but there are not many studies on its performance in different media.
What Grade is 254 SMO Stainless Steel Equivalent to?
| GRADE | UNS NO | ASTM/AISI | DIN | JIS |
| 254 SMO | S31254 | 253 SMO | 1.4547 | SUS254SMO |
Products Types of 254 SMO Stainless Steels
- 254 SMO Stainless Steel Pipe
- 254 SMO Stainless Steel Strip & Foil
- 254 SMO Stainless Steel Sheet & Plate
- 254 SMO Stainless Steel Bar
- 254 SMO Stainless Steel Custom Part
Chemical Compositions of 254 SMO Stainless Steels
| Grade | Standard | C | Si | Mn | P | S | Cr | Ni | Mo |
| 254 SMO/UNS S31254 | ASTM | ≤0.02 | ≤0.8 | ≤1.00 | ≤0.040 | ≤0.030 | 19.50-20.50 | 17.50-18.50 | 6.0-6.5 |
Mechanical Properties of 254 SMO Stainless Steels
| Grade | Tensile Strength (MPa) min. | Yield Strength 0.2% Proof (MPa) min. | Elongation | Hardness (HB) max. |
| 254 SMO/UNS S31254 | 680 | 300 | 50% | 250 |
254 SMO Stainless Steel Applications
- Marine structures in marine environment, seawater desalination, mariculture, seawater heat exchange industry
- Thermal power generation flue gas desulfurization device
- Nuclear power generation, comprehensive utilization of coal, power generation
- Oil refining, chemical equipment
- Salt making industry, soy sauce brewing industry
- Tall oil distillation columns
- Flue gas desulfurization scrubbers
- Components used in petroleum production
- Food processing equipment
- Process equipment in chemical industry
- Bleaching equipment in the pulp and paper industry
- Desalination
- Heat exchangers
Which one between Grade 254 SMO Stainless Steel and Grade 253 MA Stainless Steel is better?
The grade 254 SMO has excellent resistance to crevice and pitting corrosion, cracking corrosion and stress chloride corrosion.
All these properties are shown by grade 254 SMO due to adding more nickel and molybdenum contents in its composition.
Therefore grade 254 SMO maintains its quality under such conditions better than grade 253 MA stainless steel.
Conclusion
In conclusion, 254 SMO has a very high resistance to crevice and surface corrosion.
Alloy 254 SMO was specially developed for the pulp and paper industry and for offshore use on oil and gas platforms.
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