254SMO Stainless Steel
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| Sheets/Plates | Thickness: 0.5–50mm; Width: 600–2500mm | ASTM A240, EN 1.4547 |
| Coils | Thickness: 0.5–6mm; Width: 10–1500mm | EN 10088-3, DIN 17443 |
| Bars/Rods | Diameter: 5–500mm; Length: 1–12m | ASTM A276, ASTM A479 |
| Tubes/Pipes | OD: 10–1200mm; Wall Thickness: 1–50mm | ASTM B677, ASTM A312 |
| Fittings/Flanges | ANSI B16.5, DIN, JIS standards | ASME B16.9, EN 10253 |
Custom sizes (±5% tolerance), finishes (e.g., 2B, No.4, electropolished), and certifications available.
What is 254SMO Stainless Steel?
254SMO (UNS S31254, EN 1.4547) is a super austenitic stainless steel renowned for its exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC). With high levels of molybdenum (6%), chromium (20%), and nitrogen (0.18–0.25%), it outperforms standard austenitic grades like 316L and 904L in chloride-rich and acidic environments. Huaxiao-Alloy, as a premier
Applications of 254SMO Stainless Steel
Critical Industrial Uses
Marine & Offshore: Seawater desalination plants, heat exchangers, and offshore platform components. Chemical Processing: Reactors, piping, and tanks for sulfuric, hydrochloric, and phosphoric acid handling. Oil & Gas: Sour gas pipelines, scrubbers, and flue gas desulfurization (FGD) systems. Pharmaceuticals: CIP (clean-in-place) systems, bioreactors, and chemical storage tanks. Power Generation: Condensers and cooling systems in coastal power plants.
Certifications: ISO 9001:2015, NACE MR0175, and PED 2014/68/EU compliance. Custom Fabrication: Precision machining, welding, and surface finishing (e.g., electropolishing). Global Logistics: Efficient delivery to Europe, Asia, and the Americas.
Chemical Composition of 254SMO Stainless Steel
The exceptional corrosion resistance of 254SMO stems from its high alloy content:
| Chromium (Cr) | 19.5–20.5 | Enhances oxidation resistance. |
| Nickel (Ni) | 17.5–18.5 | Stabilizes austenitic structure. |
| Molybdenum (Mo) | 6.0–6.5 | Resists pitting and crevice corrosion. |
| Nitrogen (N) | 0.18–0.25 | Enhances strength and corrosion resistance. |
| Copper (Cu) | 0.5–1.0 | Improves resistance to sulfuric acid. |
| Manganese (Mn) | ≤1.0 | Enhances hot workability. |
| Carbon (C) | ≤0.02 | Minimizes carbide precipitation. |
| Silicon (Si) | ≤0.8 | Deoxidizer during smelting. |
| Iron (Fe) | Balance | Base metal. |
Complies with UNS S31254, EN 1.4547, and ASTM A240 specifications.
Mechanical Properties of 254SMO Stainless Steel
254SMO stainless steel offers robust performance under extreme conditions:
| Tensile Strength | 650–850 MPa |
| Yield Strength (0.2% offset) | 300 MPa (min) |
| Elongation (50mm gauge) | 35% (min) |
| Hardness (Brinell) | 200–240 HB |
| Modulus of Elasticity | 200 GPa |
Note: Solution annealing at 1150–1200°C followed by rapid cooling optimizes properties.
Physical Properties of 254SMO Stainless Steel
| Density | 8,000 kg/m³ |
| Melting Point | 1320–1400°C |
| Thermal Conductivity | 12 W/m·K (at 100°C) |
| Electrical Resistivity | 0.85 μΩ·m |
| Magnetic Permeability | <1.02 (Non-magnetic) |
254SMO vs 316L vs 904L Stainless Steel: Key Differences
| Molybdenum Content | 6–6.5% | 2–3% | 4–5% |
| PREN* Value | ≥43 | ~26 | ~36 |
| Corrosion Resistance | Superior in chlorides, acids, and sour gas | Moderate in mild chlorides | High in sulfuric acid |
| Cost | Highest | Lower | Moderate |
| Applications | Extreme marine, FGD systems | General-purpose | Chemical processing |
Its high molybdenum (6%) and nitrogen content provide exceptional resistance to pitting and crevice corrosion in chloride-rich environments.
Yes, using matching filler materials (e.g., ERNiCrMo-3) and proper shielding gas (Ar + 2–3% N₂). Post-weld heat treatment is not required.
Yes, it resits sulfuric acid up to 95% concentration at moderate temperatures.
We provide Mill Test Reports (MTRs), ISO 9001, and NACE MR0175 compliance for sour service.
254SMO offers better chloride resistance but lower mechanical strength than duplex grades.
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