Materials · Duplex and super austenitic
254SMO fasteners
HAGUE FASTENERS makes 254SMO fasteners to order: bolts, studs, nuts and machined parts in 254SMO (UNS S31254), the 6% molybdenum austenitic stainless steel for seawater and high chloride service, made to your drawing in Willenhall.
S31254
Also F44, 1.4547 and 6Mo
6 to 6.5% Mo
Molybdenum for pitting resistance
B8MLCuN
ASTM A193 bolting grade
1 to 500
Prototypes to batches of several hundred
About the alloy
Maximum pitting resistance in a stainless steel
HAGUE FASTENERS makes 254SMO fasteners in the UK for seawater, brackish water and high chloride process streams. 254SMO is an austenitic stainless steel designed for maximum resistance to pitting and crevice corrosion, with high levels of chromium, molybdenum and nitrogen.
It is commonly supplied to the ASTM petrochemical bolting standards A193 B8MLCuN for bolts and studs and A194 8MLCuN for nuts. It sits alongside duplex and super duplex as an option for chloride service, and is chosen where an austenitic, non-magnetic steel is preferred.
At a glance
- 6% molybdenum super austenitic stainless steel
- Resists pitting and crevice corrosion in chlorides
- ASTM A193 B8MLCuN and A194 8MLCuN
- NORSOK MDS R17
Composition
254SMO chemical composition
Percentage by weight.
| Element | Min % | Max % |
|---|---|---|
| Nickel (Ni) | 17.50 | 18.50 |
| Molybdenum (Mo) | 6.0 | 6.50 |
| Silicon (Si) | – | 0.80 |
| Chromium (Cr) | 19.50 | 20.50 |
| Carbon (C) | – | 0.02 |
| Manganese (Mn) | – | 1.00 |
| Nitrogen (N) | 0.18 | 0.22 |
| Sulphur (S) | – | 0.01 |
| Phosphorus (P) | – | .03 |
| Copper (Cu) | 0.50 | 1.00 |
| Iron (Fe) | Bal. | – |
Properties
Mechanical properties
Typical strength with minimum elongation and reduction of area.
| Property | Value |
|---|---|
| Tensile strength | 650 MPa |
| Yield strength (0.2% offset) | 300 MPa |
| Elongation in 2 in (50 mm) or 4D, min. | 35% |
| Reduction of area, min. | 50% |
| Hardness | 270 BHN max. |
This data is for general information only and may change without notice. HAGUE FASTENERS LIMITED believes it to be accurate but gives no warranty as to its accuracy or completeness and accepts no liability for its use. Actual properties may vary, and nothing here guarantees suitability for a particular use.
Equivalents and applications
254SMO equivalents and typical uses
Alternative designations
X1 CrNiMoCuN 20-18-7, F44, S31254, Z1 CNDU 20-18-06 Az, SS2378, 254SMO, 6Mo / SMO, MDS R17, 1.4547, ASTM A193 B8MLCuN and ASTM A194 8MLCuN.
Typical applications
- Seawater and brackish water systems
- Pulp mill bleach plants
- High chloride process streams
- Petrochemical bolting
What we make
Fasteners we make in 254SMO
Certification and testing
Certified, traceable and tested
Bar comes from approved UK, EU or US mills, with heat numbers carried through to release. Testing is by independent UKAS-accredited laboratories, with EN 10204 3.1 or 3.2 certificates as required. See quality and testing.
- Mill certificates and heat traceability
- PMI and chemical analysis
- Solution annealing by approved partners, with furnace charts
- Laser-marked heat codes or part numbers
Questions
Frequently asked questions
What is the equivalent of 254SMO?
254SMO is UNS S31254, F44 and 1.4547, often called 6Mo. For bolting it is supplied as ASTM A193 B8MLCuN and A194 8MLCuN.
Can you make 254SMO fasteners to ASTM A193 B8MLCuN?
Yes. We make 254SMO fasteners as studs and bolts to A193 B8MLCuN and nuts to A194 8MLCuN, with certificates and test reports.
Is 254SMO magnetic?
No. 254SMO is a fully austenitic stainless steel and is non-magnetic in the annealed condition.
Is 254SMO a duplex steel?
No. 254SMO is a super austenitic stainless steel. It is listed with our duplex grades because it is used for similar seawater and chloride duty.
254SMO enquiry?
Send us your drawing or specification
Tell us the sizes, quantity and documentation you need, and we will reply quickly.