Incoloy 800HT Socket head cap screws
ISO 4762ASTM B408
Where tool access is axial, Incoloy 800HT socket head cap screws bring tightly controlled carbon and Al + Ti for creep duty into a compact head envelope. Counterbore seating and housing-thread engagement determine how the available strength is used.
- 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
Partial thread
Use where a plain grip must span the clamped components. Match the under-head length and thread length so the screw tightens the stack before its thread runout reaches the tapped hole.
Full thread
Use for shorter component stacks and varied tapped-hole depths. The longer usable thread offers adjustment, while the screw end must clear the bottom of a blind hole.
- Drive
- Internal hex socket
- Length basis
- Under head
- Thread systems
- Metric · UNC · UNF · UNJ
- Assembly
- Tapped holes · Nuts
- Final condition
- Solution annealed (≥1149°C / 2100°F)
- Inspection
- Thread gauges · Head and shank dimensions
Manufacturing route
CNC machining suits samples and small lots. Cold heading or hot forging is selected for volume production according to alloy formability, head section and size.
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
Head geometry, bearing face, shank and thread fit are checked after the final machining and thermal operations.
Where 800HT fits — and what matters
Furnaces & Heat Treatment
Retort and furnace-access coversIncoloy 800HT socket head cap screws fasten retort and furnace-access covers with axial tool access inside a head counterbore. The socket and under-head seat remain accessible for service removal. Hot dwell, thermal expansion and repeated furnace cycles set the working load.
Power & Turbines
Hot-gas access covers and inspection closuresIncoloy 800HT socket head cap screws fasten hot-gas access covers and inspection closures with axial tool access inside a head counterbore. The socket and under-head seat remain accessible for service removal. Hot dwell and start-stop expansion act on the supported or moving component.
Chemical Processing
Reformer access covers and hot-gas inspection closuresIncoloy 800HT socket head cap screws fasten reformer access covers and hot-gas inspection closures with axial tool access inside a head counterbore. The socket and under-head seat remain accessible for service removal. These parts work in the heated equipment zone, where sustained loading and thermal expansion govern their section and clearance.
Same socket head cap screw. 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 gauges · Head and shank dimensions
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your 800HT socket head cap screw enquiry
Questions about 800HT socket head cap screws
What changes when the screw is stronger than the housing?
The housing thread can strip before the screw reaches its tensile capacity. The engagement depth and housing material therefore belong in the joint assessment alongside the screw’s final strength condition.