
Incoloy 800 12-point flange bolts
ASME B18.2.5MASTM B408
Incoloy 800 twelve-point flange bolts suit connections with restricted tool indexing and a compact head envelope. The material contributes heat and oxidation resistance for thermal equipment; the drive profile and flange transmit installation torque and clamp load.
- 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
Threads · Metric
Threads · Inch
Dimension Reference
Heat Treatment
AnnealedAnnealing reduces work hardening and restores ductility for the specified supplied condition.
What we can make in Alloy 800
Fully threaded / Partially threaded
The difference is the plain shank. Fully threaded bolts have threads along the shank up to the head transition; partially threaded bolts retain an unthreaded grip section beneath the flange.
External head / Internal recess
The difference is where the tool engages. An external 12-point head is gripped around its outside by a matching socket. An internal spline recess is driven by a bit inserted into the head. These are different drive structures and should not be specified interchangeably.
- Drive
- External 12-point
- Bearing
- Integral flange
- Length basis
- Under flange
- Threads
- Metric · UNC · UNF · UNJ
- Final condition
- Annealed
- 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
The ordered annealed or solution-treated state is retained in the lot record; forming and machining do not replace the specified thermal condition.
Finished geometry
Head geometry, bearing face, shank and thread fit are checked after the final machining and thermal operations.
Where 800 fits — and what matters

Furnaces & Heat Treatment
Heat-treatment fixturesIncoloy 800 12-point flange bolts fasten heat-treatment fixtures where a 12-point socket gives useful indexing around restricted equipment access. The flange supports the loaded head seat. Hot dwell, thermal expansion and repeated furnace cycles set the working load.

Power & Turbines
Boiler-duct supports and hot auxiliary bracketsIncoloy 800 12-point flange bolts fasten boiler-duct supports and hot auxiliary brackets where a 12-point socket gives useful indexing around restricted equipment access. The flange supports the loaded head seat. Hot dwell and start-stop expansion act on the supported or moving component.

Chemical Processing
Reformer tube-support and heater fixturesIncoloy 800 12-point flange bolts fasten reformer tube-support and heater fixtures where a 12-point socket gives useful indexing around restricted equipment access. The flange supports the loaded head seat. These parts work in the heated equipment zone, where sustained loading and thermal expansion govern their section and clearance.
Same 12-point flange bolt. Different material priorities.
Incoloy 800 material dataIncoloy 800
UNS N08800 · Current grade- 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- 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 N08800 · heat number · ordered condition
- Final-part acceptance
- Grade chemistry, supplied condition and ordered mechanical requirements.
- Dimensional record
- Thread gauges · Head and shank dimensions
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your 800 12-point flange bolt enquiry
Questions about 800 12-point flange bolts
Does a twelve-point head establish a higher bolt strength?
The drive profile provides tool access. Strength comes from the specified alloy, final condition and section; head engagement and flange bearing still have to transmit the installation and service loads.