Stockist & supplier ASTM A240 · ASME SA-240 · ASTM A480
254 SMO Plates — ASTM A240 UNS S31254
254 SMO plate is a 6% molybdenum super-austenitic stainless steel plate (UNS S31254) for seawater and high-chloride service. Teshi Group stocks and supplies ASTM A240 / ASME SA-240 UNS S31254 plate and sheet. Quotes are sent in 24–48 hours.
Also called: 254 SMO plate, UNS S31254 plate, 6Mo plate, 1.4547 plate, super austenitic 6Mo plate
What is a 254 SMO Plate?
UNS S31254, widely known by the trade name 254 SMO, is a super-austenitic stainless steel with about 20% chromium, 18% nickel, 6–6.5% molybdenum, nitrogen and copper. It has high resistance to pitting and crevice corrosion in seawater and chloride-bearing process streams, and good resistance to stress-corrosion cracking. Being austenitic, it remains tough at low temperature and is easier to form than duplex grades. It is used for seawater heat exchangers, desalination, bleach plants in pulp and paper, flue gas cleaning and offshore systems.
Key features
- Stockist and supplier — sourced from stainless mills; Teshi does not manufacture plate
- ASTM A240 / ASME SA-240 UNS S31254 (6Mo)
- 6.0–6.5% molybdenum for seawater pitting resistance
- Austenitic structure — tough and formable
- Plate and sheet; other sizes supplied against order
- Matching flanges and fittings manufactured by Teshi against order
Specification
| Supply | Stockist & supplier — Teshi Group, India, India |
|---|---|
| Standard | ASTM A240 / ASME SA-240; general requirements ASTM A480 |
| Grades | S31254 (6Mo, known as 254 SMO) |
| Product forms | Plate (3/16 in / 4.76 mm and thicker per ASTM A480), sheet and coil; other sizes supplied against order |
| Condition | Solution annealed and descaled (pickled) |
| Finish | No.1 (hot rolled, annealed, pickled) for plate; 2B, BA or No. 4 for sheet |
| Testing | Chemical and tensile tests per A240; intergranular corrosion test (ASTM A262) when specified |
| Documents | Mill test certificate to EN 10204 3.1; EN 10204 3.2 / third-party inspection when the order specifies |
Applications
- Seawater heat exchangers and piping
- Desalination plant
- Pulp and paper bleach plant
- Flue gas cleaning
- Offshore and marine systems
Chemical composition — UNS S31254 (ASTM A240)
| UNS | C | Mn | P | S | Si | Cr | Ni | Mo | N | Cu |
|---|---|---|---|---|---|---|---|---|---|---|
| S31254 | 0.020 | 1.00 | 0.030 | 0.010 | 0.80 | 19.5–20.5 | 17.5–18.5 | 6.0–6.5 | 0.18–0.22 | 0.50–1.00 |
Maximum unless a range is shown; % by weight. Per ASTM A240 Table 1.
Mechanical properties
| Product form | Tensile, min (MPa) | Yield 0.2%, min (MPa) | Elongation in 50 mm, min (%) | Hardness, max |
|---|---|---|---|---|
| S31254 plate | 655 | 310 | 35 | 223 HBW / 96 HRB |
| S31254 sheet and strip | 690 | 310 | 35 | 223 HBW / 96 HRB |
Per ASTM A240 Table 2.
Technical data sheets
Dimensions & weights
FAQ
254 SMO Plate: common questions
Is 254 SMO a brand name?
Yes. 254 SMO is a trade name; the grade is designated UNS S31254 and is supplied by several mills under ASTM A240. Order by UNS number.
How does S31254 compare with 316L?
S31254 has about three times the molybdenum of 316L plus nitrogen, giving far higher resistance to pitting and crevice corrosion in seawater. It is often used as an alternative to duplex in seawater.
Why are plate and sheet strengths different?
ASTM A240 sets 655 MPa minimum tensile for S31254 plate and 690 MPa for sheet and strip; yield (310 MPa) and elongation are the same.
Does Teshi manufacture 254 SMO plate?
No. Teshi Group is a stockist and supplier of 254 SMO Plate, sourced from established mills and supplied with the original mill test certificate. Teshi is an OEM manufacturer of flanges, fittings, fasteners, valves and custom fabrications, which can be ordered with it.
Need a size or grade not listed here?
We source against your specification from approved mills, with mill test certificates and inspection before dispatch.
Send us your specificationTraceability
From mill heat to your site
- 01
Approved mill material
Received against the mill certificate; heat number registered.
- 02
Forging & machining
Heat number carried through every stage in our Indian works.
- 03
PMI, dimensional & NDT
Every lot inspected to the governing standard; TPI witness on request.
- 04
Stamped & certified dispatch
Hard-stamped pieces with EN 10204 3.1 / 3.2 certificates.
Quick RFQ
Quote for 254 SMO Plate in 24–48 hours
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