Inconel 625 Heavy Hex Nuts
ASME B18.2.2ASTM B446
Inconel 625 heavy hex nuts pair a solid-solution nickel-chromium-molybdenum alloy with a larger bearing face for high-load seawater and wet-process bolt systems. Paired with matching 625 bolts and studs, they distribute bearing load and support full thread engagement.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Annealed / solution 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 or solution annealedFor B446 stock, Grade 1 is annealed and Grade 2 is solution annealed; the higher-temperature solution treatment supports creep resistance rather than age hardening.
What we can make in Alloy 625
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 · 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 625 fits — and what matters
Seawater pumps
Inconel 625 Heavy Hex NutsSeawater trapped beneath pump-cover nuts can attack the bearing face as well as the visible threads. Inconel 625 heavy hex nuts bring localized-corrosion resistance to both surfaces. Their broader pattern suits substantial pump studs and machined spotfaces, with enough wrenching area for controlled assembly and subsequent overhaul.
Connection requirements
- Mating bolt diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Seawater exposure, and heat-number certification
Subsea & ROV connections
Inconel 625 Heavy Hex NutsSubsea connection nuts can spend long periods in seawater before being handled again. Inconel 625 offers resistance to chloride attack at the loaded thread and bearing interfaces. The heavy hex pattern gives a robust tooling surface where the ROV tooling envelope and connection drawing allow that nut size.
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Seawater exposure, access constraints, and heat-number certification
Flue-gas desulfurization (FGD) ducts
Inconel 625 Heavy Hex NutsInconel 625 heavy hex nuts carry access-cover stud loads in FGD equipment where chloride-bearing condensate collects at the fastening points. Resistance to pitting and crevice corrosion is useful inside the threads and beneath the seating face, even after exposed surfaces have dried. The broad nut pattern fits substantial cover spotfaces and gives maintenance tools a larger surface to engage.
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Chloride and acid exposure, and heat-number certification
Same heavy hex nut. Different material priorities.
Inconel 625 material dataInconel 718 Heavy Hex Nuts
High-load turbine casing and hot-valve studs transfer their tension through the nut into the cover. Inconel 718 heavy hex nuts combine precipitation-hardened strength with the bearing area of a heavy pattern. Broad flats provide substantial socket engagement on these loaded, serviceable connections.
Hastelloy C-276 Heavy Hex Nuts
Hastelloy C-276 heavy hex nuts carry stud loads at corrosive reactor and exchanger covers. Their broad seating faces suit substantial spotfaces, and the alloy resists attack inside the loaded threads and beneath the nut. The heavy pattern is useful where maintenance tooling has adequate clearance.
Monel 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.
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 N06625 · 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 625 heavy hex nut enquiry
Questions about 625 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.