Hastelloy B-3 Hex Nuts
ISO 4032ASTM B335
Hastelloy B-3 hex nuts pair a nickel-molybdenum alloy with improved thermal stability relative to B-2 with standard-height mating nuts for autoclave, reactor, and pickling joints in hot reducing-acid service. Compared with B-2, B-3 forms embrittling phases more slowly during intermediate-temperature exposure, giving more processing flexibility while retaining resistance to reducing acids.
- 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 dissolves detrimental precipitates, followed by rapid cooling to preserve corrosion resistance.
What we can make in Hastelloy B-3
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 B-3 fits — and what matters
Reactor vessel & manway flanges
Hastelloy B-3 Hex NutsRegular hex B-3 nuts fit crowded reactor accessory studs and smaller reducing-acid cover connections. They protect the loaded internal threads and seating face from compatible acid exposure. The compact pattern helps where a heavy hex nut would interfere with neighbouring hardware or restrict tool access.
Connection requirements
- Hastelloy B-3 Hex Nuts · finished condition and load requirement
- Hex dimensions, seating area and nut proof load
- Acid composition, temperature and oxidizing impurities
Acid heat exchangers & condensers
Hastelloy B-3 Hex NutsHastelloy B-3 hex nuts fasten closely spaced exchanger-cover studs exposed to reducing-acid leakage. Their corrosion resistance is useful inside the loaded threads, where acid can remain after the outer cover dries. The regular pattern preserves room for a socket between neighbouring studs during cover removal.
Connection requirements
- Hastelloy B-3 Hex Nuts · finished condition and load requirement
- Hex dimensions, seating area and nut proof load
- Acid composition, temperature and oxidizing impurities
Pickling tank & acid-bath hardware
Hastelloy B-3 Hex NutsAround compatible reducing-acid pickling equipment, B-3 nuts secure compact cover and auxiliary attachments. Their internal threads see the same splash and condensate as the mating fastener. Selecting the pair together prevents the nut from becoming the chemically weaker component at an otherwise resistant connection.
Connection requirements
- Hastelloy B-3 Hex Nuts · finished condition and load requirement
- Hex dimensions, seating area and nut proof load
- Acid composition, temperature and oxidizing impurities
Same hex nut. Different material priorities.
Hastelloy B-3 material dataHastelloy B-2 Hex Nuts
Hastelloy B-2 hex nuts fit crowded reactor and pump connections in compatible reducing-acid service. Nickel-molybdenum chemistry resists acid retained at the internal threads and seating face. The compact pattern leaves tooling clearance, with oxidizing impurities remaining a critical material-selection limit.
Hastelloy C-276 Hex Nuts
Hastelloy C-276 hex nuts provide a compact corrosion-resistant component for crowded reactor, exchanger and scrubber connections. Aggressive liquid can reach both the internal threads and seating face. The regular pattern preserves tool clearance where heavy hex nuts would occupy too much space.
Hastelloy 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.
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 N10675 · 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 B-3 hex nut enquiry
Questions about B-3 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.