310S Hex nuts
ISO 4032
310S nuts place low-carbon heat resistance in oxidation-exposed equipment 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
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 annealedSolution annealing and rapid cooling retain alloying elements in solution and restore the specified corrosion-resistant condition.
What we can make in 310S
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
- 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
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
Internal thread gauging, usable engagement and bearing-face alignment are checked after final processing.
Where 310S fits — and what matters
Furnaces & Heat Treatment
Retort and furnace-access covers310S 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 closures310S 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 closures310S 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.
310S material dataIncoloy 800HT
Tightly controlled carbon and Al + Ti for creep duty.
- Connection priority
- Thread-stripping resistance and bearing pressure
- 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 internal threads and the nut-bearing face, 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
- Thread-stripping resistance and bearing pressure
- 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 internal threads and the nut-bearing face, 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
- Thread-stripping resistance and bearing pressure
- 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 internal threads and the nut-bearing face, 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 S31008 · heat number · ordered condition
- Final-part acceptance
- Grade chemistry, supplied condition and ordered mechanical requirements.
- 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 310S hex nut enquiry
Questions about 310S 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.