Introduction

254 SMO super austenitic stainless steel (high molybdenum, high alloy) is a 254 SMO corrosion resistant stainless steel with an exceptionally high PREN value (42–45). It delivers excellent pitting resistance, crevice corrosion resistance, and outstanding chloride corrosion resistance for seawater service. Whether you need a 254 SMO stainless steel plate supplier or finished components, this grade outperforms 316L and duplex in marine and chemical environments.

Chemical components (%)

Mechanical properties

Physical properties

254 SMO Stainless Steel  Available Products and Standard

1. ASTM A240 / ASME SA240 

(Chromium and Chromium‑Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and General Applications)

Grade: UNS S31254 / 254 SMO (W.Nr. 1.4547) – 254 SMO super austenitic stainless steel, 254 SMO high molybdenum stainless steel
Type: 

• 254 SMO stainless steel Plate

• 254 SMO stainless steel Sheet

• 254 SMO stainless steel Strip

Size Range:

• Thickness: 0.02 – 100 mm (cold‑rolled or hot‑rolled)

• Width: 900 – 2400 mm (customised)

• Length: 2000 – 12000 mm (customised)

Surface: Annealed, Pickled, Bright, No.1 (hot‑rolled), 2B (cold‑rolled), BA, No.4, Mirror, SATIN

Testing: Chemical analysis, tensile test (Rm ≥650 MPa, Rp0.2 ≥300 MPa), elongation (≥35%), hardness (≤270 HBN), pitting corrosion test, crevice corrosion test, intergranular corrosion test, flattening test, hydrostatic test, dimensional inspection

2. EN 10088‑2 

(Stainless Steels – Technical Delivery Conditions for Sheet/Plate and Strip of Corrosion Resisting Steels for General Purposes)

Grade: X1CrNiMoCuN20‑18‑7 / 1.4547 – 254 SMO high alloy stainless steel (PREN ≥42.5, exceptional pitting & crevice resistance)
Type: 

• 254 SMO stainless steel Hot‑rolled plate

• 254 SMO stainless steel Cold‑rolled sheet

• 254 SMO stainless steel Strip

Size Range:

• Thickness: 0.5 – 80 mm

• Width: up to 3500 mm

• Length: up to 12000 mm

Surface: Annealed, Pickled, Bright, 1D, 2B, 2D, BA

Testing: Chemical analysis, tensile test (Rm ≥650 MPa, Rp0.2 ≥300 MPa), elongation test, flattening test (for strip), pitting corrosion test, crevice corrosion test, eddy current test (optional), dimensional inspection

3. JIS G4304 / G4305 

(Hot‑Rolled / Cold‑Rolled Stainless Steel Plate, Sheet and Strip)

Grade: SUS312L / SUS329J4L (Japanese equivalent to UNS S31254) – 254 SMO stainless steel plate supplier choice for marine & chemical services
Type: 

• 254 SMO stainless steel Hot‑rolled plate (G4304)

• 254 SMO stainless steel Cold‑rolled sheet and strip (G4305)

Size Range:

• Thickness: 0.3 – 150 mm

• Width: 1000 / 1219 / 1500 / 1800 / 2000 mm

• Common Sizes: 1219×2438 mm (4′×8′), 1500×6000 mm

Surface: No.1 (hot‑rolled), 2B, BA, No.4, HL, Mirror

Testing: Chemical composition verification (Cr 19.5–20.5%, Mo 6.0–6.5%, N 0.18–0.22%, Cu 0.5–1.0%, C ≤0.020%), tensile test (Rm ≥650 MPa, Rp0.2 ≥300 MPa), elongation (≥35%), flattening test, intergranular corrosion test, pitting corrosion test, crevice corrosion test, dimensional inspection

4. ASTM A789 / A790 

(Seamless and Welded Ferritic/Austenitic Stainless Steel Tube / Pipe for General Corrosive Service)

Grade: UNS S31254 / 254 SMO – 254 SMO stainless steel for seawater, 254 SMO chloride corrosion resistance
Type: 

• 254 SMO stainless steel Seamless

• 254 SMO stainless steel Welded Tube and Pipe (round)

Size Range:

• Seamless OD: 6.0 – 250 mm (up to 12″ NB)

• Welded OD: up to 1219 mm

• Wall thickness: 0.5 – 50 mm

Surface: Annealed, Pickled, Bright, Polished

Testing: Chemical analysis, tensile test, flattening test (for welded pipe), flaring test (for seamless pipe), hydrostatic or NDE test, pitting corrosion test, crevice corrosion test, SSC test (per NACE MR0175), dimensional inspection

Applications

(1) Desalination – With a PREN value exceeding 42, 254 SMO high molybdenum stainless steel provides excellent pitting and crevice resistance in hot seawater brine, making it the standard choice for evaporators, high‑pressure piping, and brine heaters in desalination plants.

(2) Seawater system – 254 SMO stainless steel for seawater systems (intake screens, pumps, valves, heat exchangers) offers superior chloride corrosion resistance and outstanding crevice corrosion resistance, eliminating the rapid pitting failure seen with 316L.

(3) Offshore platform – As a high alloy stainless steel with exceptional chloride resistance, 254 SMO withstands splash zone corrosion, seawater immersion, and firewater service on offshore platforms, reducing maintenance and life‑cycle costs.

(4) Chemical processing – 254 SMO super austenitic stainless steel handles mineral acids (sulfuric, hydrochloric), organic acids, and aggressive chlorinated media where standard austenitic grades fail, thanks to its high molybdenum and nitrogen content.

(5) Flue gas desulfurization (FGD) – 254 SMO stainless steel for FGD scrubbers, outlet ducts, and dampers provides excellent resistance to localized corrosion from chlorides, sulfurous acids, and high temperatures, ensuring long service life in the most severe corrosion zones.

(6) Marine environment – From boat hulls and propeller shafts to marine exhaust systems, 254 SMO corrosion resistant stainless steel delivers decades of reliable performance in saltwater exposure, with its high PREN value and proven resistance to both pitting and crevice corrosion.

MONO Group is one of 254 SMO Stainless Steel Manufacturer&Supplier&Wholesaler from China,We can supply ASTM /DIN/ISO/GB stndard high quality alloy plate,sheet,round bar,tube.pipes,fittings,flange,pls contact us freely for your RFQ to info@monokj.com