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ASTM A240 254 SMO Stainless Steel Plate UNS S31254 with 6% Molybdenum and Superior Chloride Resistance
| MOQ: | 5Ton |
| Delivery Period: | 7-15 |
| Payment Method: | L/C,D/A,D/P,T/T,Western Union |
Shaanxi Shangyou Stainless Steel Co., Ltd. supplies ASTM A240 254 SMO stainless steel plate for global distributors, fabricators, equipment manufacturers, and EPC contractors requiring maximum corrosion resistance in chloride-laden environments. Produced to ASTM A240/A240M as UNS S31254 (also equivalent to EN 1.4547, X1CrNiMoCuN20-18-7, and F44), this super austenitic stainless steel is the premier grade for seawater and aggressive chloride service.
254 SMO is distinguished by its exceptionally high molybdenum content (6.0-6.5%), combined with elevated chromium (19.5-20.5%), nickel (17.5-18.5%), and nitrogen (0.18-0.22%), plus copper (0.5-1.0%). This composition delivers a Pitting Resistance Equivalent Number (PREN) exceeding 42—substantially higher than 316L (~25) and 904L (~32)—providing outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking in seawater, brackish water, and other high-chloride environments. The alloy is also characterized by strength nearly twice that of 300 series stainless steels, high ductility, and good weldability.
| Dimension | Specification |
|---|---|
| Product Name | ASTM A240 254 SMO Stainless Steel Plate |
| Product Alias | UNS S31254 Plate / EN 1.4547 Plate / 254SMO Sheet / F44 / 6Mo Stainless Plate / 00Cr20Ni18Mo6CuN |
| Material Type | Super Austenitic Stainless Steel (6% Mo) |
| Key Feature | PREN >42 provides outstanding resistance to pitting and crevice corrosion in seawater and chloride environments; strength twice that of 300 series |
| Chemical Composition | Cr 19.5-20.5% / Ni 17.5-18.5% / Mo 6.0-6.5% / N 0.18-0.22% / Cu 0.5-1.0% / C ≤0.02% / Mn ≤1.00% / Si ≤0.80% / Fe Balance |
| Mechanical Properties | Tensile ≥655 MPa / Yield ≥310 MPa / Elongation ≥35% / Hardness 182-223 HB |
| Physical Properties | Density 8.24 g/cm3 / Melting Point 1320-1390°C / Elastic Modulus ~195 GPa / Non-magnetic |
| Manufacturing Process | Hot Rolling / Cold Rolling / Solution Annealing 1150-1200°C / Water Quenching |
| Surface Finish | 2B / BA / No.1 / No.4 / HL / 8K |
| Primary Applications | Seawater Handling / Desalination / FGD Scrubbers / Pulp Bleaching / Chemical Processing / Offshore Oil & Gas |
| Parameter | Available Options |
|---|---|
| Product Standard | ASTM A240/A240M, ASTM A480, ASME SA-240 |
| Grade Equivalents | UNS S31254 / EN 1.4547 / F44 / X1CrNiMoCuN20-18-7 |
| Thickness | Cold Rolled: 0.5-6.0mm; Hot Rolled: 3.0-80.0mm (heavier on request) |
| Width | 1000mm, 1219mm (4ft), 1500mm, 2000mm, or customized |
| Length | 2000mm-6000mm (standard 4×8ft: 1219×2438mm) or customized |
| Surface Finish | 2B / BA / No.1 / No.4 / HL / 8K |
| Edge Condition | Mill Edge / Slit Edge / Sheared Edge |
| Inspection | PMI / Tensile Test / Hardness Test / Pitting Test (ASTM G48) / Ultrasonic Test |
| Documents | MTC 3.1 / Inspection Reports / Packing List / Heat Number Traceability |
ASTM A240 254 SMO stainless steel plate is specified for the most demanding chloride-rich and acidic environments where standard grades like 316L and 904L may fail.
Typical applications include:
- Seawater handling: heat exchangers, cooling water systems, ballast water systems, firefighting systems
- Desalination equipment and saltwater handling systems
- Flue gas desulfurization (FGD) scrubbers
- Pulp mill bleach plants and chemical pulp bleaching equipment
- Chemical processing equipment handling halide-containing acids
- Offshore oil and gas production equipment
- Food processing equipment
Key selection considerations: 254 SMO offers significant advantages over 316L and 904L in chloride environments, with PREN >42 compared to ~25 for 316L and ~32 for 904L. In pure sulfuric acid, 254 SMO offers much greater corrosion resistance than 316L, though it is slightly less resistant than 904L at high concentrations. In hydrochloric acid at ambient temperatures, 254 SMO can be used in dilute concentrations where 316L cannot be used. The suggested operating range is -320°F to 1000°F (-196°C to 538°C). The alloy is approved by ASME for pressure vessel applications per Section VIII, Div. 1 and is NACE MR0175 compliant for sour service.
Shangyou Stainless Steel provides value-added processing including cut-to-length, slitting, polishing, laser cutting, bending and forming, and protective film application.
All plates are packed with export-standard protection including protective paper between sheets, edge protection, steel strapping, waterproof wrapping, and wooden pallets or steel frames.
Quality documents include MTC 3.1, inspection reports, packing list, and heat number traceability. Third-party inspection (SGS, TUV, BV) can be arranged upon request.
254 SMO (UNS S31254, EN 1.4547) is a super austenitic stainless steel alloyed with 6% molybdenum and nitrogen. It is designed for use in seawater and aggressive chloride-bearing media, offering PREN >42 and strength twice that of 300 series stainless steels.
PREN (Pitting Resistance Equivalent Number) = Cr + 3.3Mo + 16N. 254 SMO has PREN ≥42.5, significantly higher than 316L (~25) and 904L (~32).
254 SMO has 6% molybdenum (vs 2-3% in 316L), higher chromium and nickel, and nitrogen addition. This delivers PREN >42 vs ~25, with far superior resistance to pitting and crevice corrosion in chloride environments. 254 SMO is also approximately twice as strong as 316L.
Yes. 254 SMO was specifically developed for seawater and other aggressive chloride-bearing environments. It is used in seawater cooling systems, heat exchangers, ballast water systems, and offshore equipment.
Cold rolled sheet from 0.5mm to 6.0mm; hot rolled plate from 3.0mm to 80.0mm. Heavier thicknesses available on request.
254 SMO is fully austenitic and non-magnetic in the annealed condition.
Suggested operating range is -320°F to 1000°F (-196°C to 538°C).
Yes. 254 SMO offers good weldability. Care is needed to maintain properties and avoid formation of intermetallic phases. No post-weld heat treatment is generally required.
Yes. UNS S31254 in seamless pipe form has ASME approval for use according to ASME Boiler and Pressure Vessel Code Section VIII, Div. 1. It is also NACE MR0175 compliant for sour service.
Seawater handling equipment, desalination plants, FGD scrubbers, pulp mill bleach plants, chemical processing equipment, offshore oil and gas production, and food processing equipment.
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