Hastelloy C-276 Hex Nuts
ISO 4032ASTM B574
Hastelloy C-276 hex nuts pair a solid-solution nickel-molybdenum-chromium alloy with a standard-height mating nut for acid and chloride bolt systems. Paired with matching C-276 bolts and studs, they support full thread engagement within standard height.
- 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
Finished-Nut Specifications
Threads · Metric
Threads · Inch
Dimension Reference
Heat Treatment
Solution annealedSolution annealing dissolves detrimental precipitates, followed by rapid cooling to preserve corrosion resistance.
What we can make in Hastelloy C-276
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 final annealed or specified strengthened condition is linked to the lot; an aging treatment is not assumed for a solid-solution alloy.
Finished geometry
Internal thread gauging, usable engagement and bearing-face alignment are checked after final processing.
Where C-276 fits — and what matters
Reactor vessel & manway flanges
Hastelloy C-276 Hex NutsRegular hex C-276 nuts suit reactor accessory and cover connections with limited room around the studs. They provide chemical resistance at the internal threads and seating face, where deposits can remain after a leak. Their compact pattern is useful around crowded manway hardware, provided the specified nut load suits the assembly.
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Acid and chloride exposure, and heat-number certification
Acid heat exchangers & condensers
Hastelloy C-276 Hex NutsOn acid-exchanger tie rods and auxiliary cover studs, regular hex C-276 nuts leave more clearance than a heavy pattern. The alloy protects nut surfaces exposed to process drips and condensate. This is useful where corrosion resistance is required but the cover drilling and tool spaces were designed for compact nuts.
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Acid and chloride exposure, and heat-number certification
Scrubber towers & halide piping joints
Hastelloy C-276 Hex NutsScrubber access covers and small halide-piping joints often have closely spaced fasteners. C-276 hex nuts provide a compact corrosion-resistant component for those joints. Choosing the nut material alongside the stud avoids leaving a less resistant internally threaded part at the same wet, contaminated connection.
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Chloride and acid exposure, and heat-number certification
Same hex nut. Different material priorities.
Hastelloy C-276 material dataHastelloy C-22 Hex Nuts
Hastelloy C-22 hex nuts secure compact reactor, exchanger and abatement connections exposed to mixed chemical condensate. The alloy resists attack on the loaded threads and sheltered bearing face. Regular dimensions preserve tooling clearance around closely spaced cover studs and ductwork.
Hastelloy B-3 Hex Nuts
Hastelloy B-3 hex nuts suit compact cover and auxiliary connections exposed to strongly reducing acids. Their regular pattern preserves tooling space around close studs. The alloy offers improved thermal stability over B-2, with oxidizing impurities and cleaning chemistry remaining essential selection details.
Inconel 625 Hex Nuts
Inconel 625 hex nuts suit compact offshore, marine-bonnet and FGD connections exposed to wet chlorides. The alloy resists localized corrosion at internal threads and sheltered seating faces. A regular pattern leaves more tooling clearance than a heavy nut on the same nominal thread.
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 N10276 · 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 C-276 hex nut enquiry
Questions about C-276 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.