A-286 Heavy Hex Nuts
ASME B18.2.2
A-286 heavy hex nuts pair an iron-base precipitation-hardened austenitic alloy with a larger bearing face for high-load hot bolt systems. Paired with matching A-286 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
- Solution treated and aged
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
Solution treated and agedSolution treatment is followed by precipitation aging, with the Grade 660 class defining the required heat-treatment route and final properties.
What we can make in A-286
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 treated and aged
- 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
Solution treatment and the specified aging condition are recorded against the production lot; final dimensions are checked after thermal processing.
Finished geometry
Internal thread gauging, usable engagement and bearing-face alignment are checked after final processing.
Where A-286 fits — and what matters
Gas & steam turbine casing joints
A-286 Heavy Hex NutsHeavy hex A-286 nuts provide broad bearing and wrenching surfaces for hot casing studs. The precipitation-hardened alloy supports elevated-temperature loading, with proof load established by the nut specification. This is useful where a casing joint has space for a heavy pattern and requires substantial stud loads.
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Temperature range, cycling duty, and precipitation-hardened condition certification
High-pressure steam valve bonnets
A-286 Heavy Hex NutsAt a steam-valve bonnet, the nut is the accessible load-transfer component above the cover. An A-286 heavy hex nut combines hot-strength material with a generous bearing footprint. It should be ordered as part of the stud-and-nut specification so that heat treatment, thread fit and proof load are coordinated.
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Temperature range, cycling duty, and precipitation-hardened condition certification
Generator & rotor tie-bolt assemblies
A-286 Heavy Hex NutsA-286 heavy hex nuts can carry tie-bolt loads into generator end hardware where the design calls for elevated-temperature bolting. Their larger pattern provides useful bearing area and socket engagement. A rotor drawing may add balance or retention requirements that distinguish the supplied nut from ordinary stationary-equipment hardware.
Connection requirements
- Mating tie-bolt diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Load, cycling duty, and precipitation-hardened condition certification
Same heavy hex nut. Different material priorities.
A-286 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.
Nimonic 80A Heavy Hex Nuts
Nimonic 80A heavy hex nuts combine age-hardened hot strength with broad seating faces for substantial turbine, bonnet and exhaust stud assemblies. Their loaded internal threads carry the stud tension into the cover or support. Large wrenching flats suit connections with room for controlled assembly tooling.
Inconel 601 Heavy Hex Nuts
Furnace covers and robust fixture studs expose the nut directly to the hot atmosphere. Inconel 601 heavy hex nuts bring oxidation resistance to those threads and seating faces. Broad flats and a substantial bearing pattern suit support plates and cover spotfaces opened during furnace maintenance.
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 S66286 · heat number · ordered condition
- Final-part acceptance
- Lot-linked aging record and mechanical acceptance in the final condition.
- Dimensional record
- Thread plug gauges · Across flats · Nut height
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your A-286 heavy hex nut enquiry
Questions about A-286 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.