A-286 Square-head positioning bolts
ASME B18.2.1
A-286 positioning bolts separate anti-rotation at the square head from location at the shoulder. The material’s aged iron–nickel alloy strength for hot bolting applies to these loaded contact surfaces as well as the thread.
- 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
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
Square head
Capture the square head in a matching slot or pocket to stop rotation while tightening from the nut side. Head width and pocket clearance determine how much turning play remains.
Locating shank
Use a machined step or shank to locate fixture plates and adjustable tooling. Specify its fit to the mating bore when repeatable position matters; thread clearance cannot provide that locating accuracy.
- Drive
- External square
- Interface
- Head flats · Shank steps
- Length basis
- Under head
- Threads
- Metric · Inch
- Final condition
- Solution treated and aged
- Inspection
- Head flats · Locating diameter · Step lengths · Threads
Manufacturing route
CNC machining suits samples and small batches. Volume heads are formed in a workable condition with the final aging route included in process planning.
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
Head geometry, bearing face, shank and thread fit are checked after the final machining and thermal operations.
Where A-286 fits — and what matters
Furnaces & Heat Treatment
Heat-treatment fixturesA-286 square-head positioning bolts set stops and clamp positions on heat-treatment fixtures. The square head provides tool purchase while the end face or point bears on the positioned component. Hot dwell, thermal expansion and repeated furnace cycles set the working load.
Power & Turbines
Boiler-duct supports and hot auxiliary bracketsA-286 square-head positioning bolts set stops and clamp positions on boiler-duct supports and hot auxiliary brackets. The square head provides tool purchase while the end face or point bears on the positioned component. Hot dwell and start-stop expansion act on the supported or moving component.
Chemical Processing
Reformer tube-support and heater fixturesA-286 square-head positioning bolts set stops and clamp positions on reformer tube-support and heater fixtures. The square head provides tool purchase while the end face or point bears on the positioned component. These parts work in the heated equipment zone, where sustained loading and thermal expansion govern their section and clearance.
Same square-head positioning bolt. Different material priorities.
A-286 material dataIncoloy 800HT
Tightly controlled carbon and Al + Ti for creep duty.
- Connection priority
- Bearing at the locating step and reaction against the square head
- N08811 material control
- 800HT tightens the 800-family chemistry around creep performance. Its solution-treated, coarse-grain condition and N08811 identity should remain linked through forming and final acceptance. At the square-head pocket and locating shoulder, the relevant metal temperature can differ from the process or furnace set point.
Inconel 718
Precipitation-hardened strength for compact, highly loaded connections.
- Connection priority
- Bearing at the locating step and reaction against the square head
- Strength after aging
- Machine-stock properties and final aged properties describe different states. The final heat-treatment lot and mechanical results establish the strength available in the installed part. At the square-head pocket and locating shoulder, the relevant metal temperature can differ from the process or furnace set point.
310S
Low-carbon heat resistance in oxidation-exposed equipment.
- Connection priority
- Bearing at the locating step and reaction against the square head
- 310S is not 310H
- S31008 is the low-carbon grade. For a component under sustained hot load, distinguish that specification from the controlled-carbon creep purpose of S31009. At the square-head pocket and locating shoulder, the relevant metal temperature can differ from the process or furnace set point.
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
- Head flats · Locating diameter · Step lengths · Threads
- Traceability
- EN 10204 3.1 material certificate · production lot · identified packing
Build your A-286 square-head positioning bolt enquiry
Questions about A-286 square-head positioning bolts
Which tolerance should locate the component?
Use the specified shoulder or locating diameter, with a matching hole fit. Head clearance serves tool engagement or anti-rotation; it should not silently replace the drawing’s locating datum.