Stainless Steel 310H 12-point flange bolts
ASME B18.2.5M
Stainless Steel 310H twelve-point flange bolts suit connections with restricted tool indexing and a compact head envelope. The material contributes controlled-carbon stainless performance for sustained hot loading; the drive profile and flange transmit installation torque and clamp load.
- MOQ
- 100PCS
- Samples · typical
- ~20 days
- Production · typical
- 25–35 days
- Heat treatment
- Solution annealed
EN 10204 3.1 MTC + heat-number traceability
Which standard is on your order?
Threads · Metric
Threads · Inch
Dimension Reference
Heat Treatment
Solution annealedSolution annealing and rapid cooling retain alloying elements in solution and restore the specified corrosion-resistant condition.
What we can make in Stainless Steel 310H
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
- Solution 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 310H fits — and what matters
Furnaces & Heat Treatment
Heat-treatment fixturesStainless Steel 310H 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 bracketsStainless Steel 310H 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 fixturesStainless Steel 310H 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.
Stainless Steel 310H material dataIncoloy 800HT
Tightly controlled carbon and Al + Ti for creep duty.
- Connection priority
- Clamp load through a compact head envelope
- 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 compact twelve-point drive and flange-bearing surface, 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
- Clamp load through a compact head envelope
- 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 compact twelve-point drive and flange-bearing surface, the relevant metal temperature can differ from the process or furnace set point.
A-286
Aged iron–nickel alloy strength for hot bolting.
- Connection priority
- Clamp load through a compact head envelope
- Grade 660 class
- An ASTM A453 Grade 660 order includes its class and corresponding processing requirements. The alloy name A-286 alone does not identify that acceptance condition. At the compact twelve-point drive and flange-bearing surface, 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 S31009 · 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 310H 12-point flange bolt enquiry
Questions about 310H 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.