Monel 400 Heavy Hex Nuts
ASME B18.2.2ASTM B164
Monel 400 heavy hex nuts complete nickel-copper stud joints on marine pumps, valves and cooling lines. The larger hex provides a substantial wrenching surface, while the selected nut condition and proof load establish compatibility with the mating stud.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Annealed
EN 10204 3.1 MTC + heat-number traceability
Which standard is on your order?
Raw Material Specifications
Finished-Nut Specifications
Threads · Metric
Threads · Inch
Dimension Reference
Heat Treatment
Annealed; cold worked for higher strengthAnnealing restores ductility after working, while the specified amount of cold work sets higher-strength conditions without aging.
What we can make in Monel 400
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
- Annealed · Cold worked
- 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 400 fits — and what matters
Seawater pumps
Monel 400 Heavy Hex NutsThe nuts on a seawater-pump cover are removed whenever the pump is opened. Monel 400 heavy hex nuts provide a corrosion-resistant thread and a larger tool-engagement surface for this work. Their bearing face must fit the cover spotface or washer, and their proof load must support the installed stud tension.
Connection requirements
- Stud tension and nut proof load
- Socket envelope and bearing diameter
- Seawater access to engaged threads
Marine valve bonnets
Monel 400 Heavy Hex NutsA marine valve bonnet often has limited space between the stem assembly and the stud circle. Heavy hex Monel 400 nuts are useful where the larger wrenching body fits that envelope. Matching nut height to stud projection ensures full engagement without leaving excess thread in the maintenance access space.
Connection requirements
- Stem-to-stud tool clearance
- Nut height and stud projection
- Valve service water and nut condition
Shipboard cooling lines
Monel 400 Heavy Hex NutsOn shipboard cooling flanges, Monel 400 heavy hex nuts give maintenance crews a robust wrenching surface in damp, salt-laden surroundings. The nut and stud form a threaded pair, so thread fit and lubrication affect dismantling as well as tightening. Retained seawater in the nut-side crevice deserves attention during shutdown inspections.
Connection requirements
- Thread designation and fit
- Assembly lubricant
- Cooling-water stagnation and inspection access
Same heavy hex nut. Different material priorities.
Monel 400 material dataMonel K-500 Heavy Hex Nuts
A high-strength nickel-copper stud assembly needs a nut capable of carrying its load. Monel K-500 heavy hex nuts combine age-hardened strength with broad seating faces for substantial seawater-pump and bonnet spotfaces. The large flats provide engagement for assembly and overhaul tooling.
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.
Duplex 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.
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 N04400 · 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 400 heavy hex nut enquiry
Questions about 400 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.