254 SMO Heavy Hex Nuts
ASME B18.2.2ASTM A276
254 SMO heavy hex nuts suit chloride-exposed pump, exchanger and bleach-plant stud joints. The six-moly austenitic alloy brings resistance to localized corrosion at the internal threads and bearing face, with a substantial hex for overhaul tooling.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Solution annealed
EN 10204 3.1 MTC + heat-number traceability
Which standard is on your order?
Raw Material Specifications
Threads · Metric
Threads · Inch
Dimension Reference
Heat Treatment
Solution annealedSolution annealing and rapid cooling retain alloying elements in solution and restore the specified corrosion-resistant condition.
What we can make in 254 SMO
Regular hex
Use on equipment covers and mounting brackets with standard socket access. The compact wrenching envelope is useful where adjacent fasteners or housing walls restrict tool clearance.
Heavy hex
Use on flange-bolting sets and pressure-equipment joints calling for a heavy-hex pattern. The wider bearing footprint and larger wrench size require more seat area and socket clearance than a regular hex nut.
Thin hex
Use in restricted axial spaces or as part of a specified two-nut locking arrangement. Reduced thread engagement means a thin nut is not a direct load-capacity replacement for a full-height nut.
- Metric thread
- M4–M100
- Inch thread
- 1/4″–4″
- Patterns
- Heavy hex
- Thread systems
- Metric · UNC · UNF · 8UN · UNJ
- Final condition
- Solution annealed
- Inspection
- Thread plug gauges · Across flats · Nut height
Manufacturing route
Small lots use machined blanks. Volume nut blanks use a forming route compatible with the alloy before machining the bore and tapping.
Heat treatment & final condition
The final annealed or specified strengthened condition is linked to the lot; an aging treatment is not assumed for a solid-solution alloy.
Finished geometry
Internal thread gauging, usable engagement and bearing-face alignment are checked after final processing.
Where 254 SMO fits — and what matters
Bleach-plant washers & mixers (ClO2)
254 SMO Heavy Hex NutsBleach-plant cover nuts are exposed to process deposits as well as repeated wrench contact. 254 SMO heavy hex nuts combine a corrosion-resistant internal thread with a larger external hex for overhaul work. The nut must fit the available bolt-circle spacing and carry the stud tension through a fully supported bearing face.
Connection requirements
- Liquor and cleaning exposure
- Stud tension and nut proof load
- Socket and bearing-seat clearance
Plate & shell heat-exchanger covers
254 SMO Heavy Hex NutsExchanger end-cover nuts transfer the closure load onto the flange seat. 254 SMO heavy hex nuts are useful where seawater leakage or chloride deposits reach this area. Nut height and stud projection must leave full engagement and enough tool access to dismantle the cover without disturbing nearby piping.
Connection requirements
- Closure load and thread fit
- Nut height and stud projection
- Maintenance-tool access
Split-case & multistage pump casings
254 SMO Heavy Hex NutsSplit-case pump covers may need a substantial nut body within a fixed stud pattern. 254 SMO heavy hex nuts provide a six-moly austenitic option for chloride-bearing pump service. A machined spotface or washer supports the nut, and its dimensions must accommodate the full bearing face without overhanging the casing lug.
Connection requirements
- Pump fluid and external leakage
- Casing spotface dimensions
- Nut proof load and thread engagement
Same heavy hex nut. Different material priorities.
254 SMO material dataDuplex 2205 Heavy Hex Nuts
2205 heavy hex nuts suit chloride-process closures where a stronger duplex nut is useful alongside the corrosion-resistant stud. The large hex assists tightening and removal on pump and valve covers. Selecting the nut proof load and bearing seat completes the mechanical pairing; it does not follow automatically from choosing the same alloy.
Super Duplex 2507 Heavy Hex Nuts
2507 heavy hex nuts suit loaded seawater and brine stud connections that call for super duplex corrosion resistance. Their larger wrenching body assists controlled tightening and maintenance. The nut must carry the selected stud tension through its threads and bearing face, so proof-load acceptance and seat dimensions are part of the set specification.
Inconel 625 Heavy Hex Nuts
Inconel 625 heavy hex nuts suit substantial seawater and wet-chloride stud connections. Localized-corrosion resistance matters beneath the seating face and inside the loaded threads. The broad pattern fits robust pump spotfaces and subsea connections with sufficient clearance for the installation tooling.
From drawing to documented delivery
- 01Drawing & BOMForm, dimensions and quantity
- 02Material & formingGrade, heat and manufacturing route
- 03Final inspectionGeometry, threads and ordered tests
- 04Documents & dispatchLot records and identified packing
Order documents
- Material identity
- UNS S31254 · heat number · ordered condition
- Final-part acceptance
- Grade chemistry, supplied condition and ordered mechanical requirements.
- Dimensional record
- Thread plug gauges · Across flats · Nut height
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your 254 SMO heavy hex nut enquiry
Questions about 254 SMO hex nuts
Does a matching UNS make the stud and nut a matched set?
Matching chemistry addresses only one part of the order. Nut strength, effective engagement, internal thread fit and surface friction must also suit the stud and assembly tightening method.