Incoloy 800HT Hex nuts
ISO 4032ASTM B408
Incoloy 800HT nuts place tightly controlled carbon and Al + Ti for creep duty in the internal thread and bearing face of the connection. Regular or heavy hex geometry, usable engagement and final condition must match the stud or bolt.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Solution annealed (≥1149°C / 2100°F)
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 annealedThe specified solution treatment develops the controlled grain structure needed for sustained high-temperature creep duty.
What we can make in Alloy 800HT
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
- Regular hex · Heavy hex
- Thread systems
- Metric · UNC · UNF · 8UN · UNJ
- Final condition
- Solution annealed (≥1149°C / 2100°F)
- 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 annealing at a minimum of 1149°C (2100°F) establishes the coarse-grain condition used for creep resistance. The heat-treatment record and grain-size result identify this delivery state.
Finished geometry
Internal thread gauging, usable engagement and bearing-face alignment are checked after final processing.
Where 800HT fits — and what matters
Furnaces & Heat Treatment
Retort and furnace-access coversIncoloy 800HT hex nuts complete the stud connections on retort and furnace-access covers. The nut pattern provides the bearing area and thread engagement for the selected stud and tightening method. Hot dwell, thermal expansion and repeated furnace cycles set the working load.
Power & Turbines
Hot-gas access covers and inspection closuresIncoloy 800HT hex nuts complete the stud connections on hot-gas access covers and inspection closures. The nut pattern provides the bearing area and thread engagement for the selected stud and tightening method. Hot dwell and start-stop expansion act on the supported or moving component.
Chemical Processing
Reformer access covers and hot-gas inspection closuresIncoloy 800HT hex nuts complete the stud connections on reformer access covers and hot-gas inspection closures. The nut pattern provides the bearing area and thread engagement for the selected stud and tightening method. These parts work in the heated equipment zone, where sustained loading and thermal expansion govern their section and clearance.
Same hex nut. Different material priorities.
Incoloy 800HT material dataIncoloy 800
UNS N08800- Carbon
- ≤0.10%
- What changes
- General heat and oxidation resistance; no grain-size requirement in the family comparison.
Incoloy 800H
UNS N08810- Carbon
- 0.05–0.10%
- What changes
- Controlled carbon and coarse-grain condition for creep and stress-rupture duty.
Incoloy 800HT
UNS N08811 · Current grade- Carbon
- 0.06–0.10%
- What changes
- Tighter carbon and Al + Ti control (0.85–1.20%), with solution treatment and coarse grain for creep duty.
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 N08811 · heat number · ordered condition
- Final-part acceptance
- UNS grade, carbon and alloy chemistry, solution-treatment record and ordered grain-size evidence.
- Dimensional record
- Thread plug gauges · Across flats · Nut height
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Matching Kit
Flange Stud Bolt Kits
Build your 800HT hex nut enquiry
Questions about 800HT 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.