Special alloy fasteners for Chemical Processing.
Bolts and stud sets that resist process corrosion at reactor covers, valves and pump joints. Supplied as individual parts or equipment kits.
Which fasteners fit your chemical-processing applications?
BYBOLT supplies Hastelloy C-276 stud & nut sets for corrosive reactor-cover joints, Hastelloy C-22 double-end studs for oxidizing chemical service, and Alloy 20 hex bolts for sulfuric-acid equipment. Inconel 625 hex flange bolts combine corrosion resistance with a wider bearing face for process-equipment attachments. Send one drawing or your full shutdown list.
Fasteners for chemical-processing equipment.
Agitator & mixer shafts (in-vessel)
Rotating shafts inside acid vessels face continuous splash, vibration and crevice exposure at seals and couplings. Hastelloy C-276 studs hold impellers and couplings securely while resisting localised attack where deposits collect.
Hastelloy C-276 shaft studsConnection requirements
- Shaft coupling bolt circle and thread engagement length
- Seal-face bearing surface finish and flatness
- Stud material grade and thread form specification
Reactor vessel & manway flanges
At reactor manways, C-276 studs are candidates where process leakage or condensate repeatedly wets the flange threads. Their corrosion resistance matters both during operation and when the nuts are removed at shutdown. On tapped-stud designs, the cover can be serviced without withdrawing the studs from the flange.
Hastelloy C-276 Stud BoltsRelated material guides
Connection requirements
- Vessel flange thickness, gasket type, and required preload
- Stud diameter, overall length, and nut engagement at each end
- Acid and chloride exposure, and heat-number certification
Acid heat exchangers & condensers
On reducing-acid exchanger accessories, B-2 socket screws can secure small covers and recessed mounting blocks. The alloy protects loaded screw surfaces from compatible acid exposure, and the socket head gives access in crowded locations. These are compact equipment fastenings, distinct from the exchanger's main flange studs.
Hastelloy B-2 Socket Head Cap ScrewsRelated material guides
Connection requirements
- Tapped-hole size, thread form, and effective engagement depth
- Head diameter, head height, and counterbore clearance required
- Reducing-acid chemistry, oxidising-contaminant exclusion, and heat-number certification
Chemical transfer pump casings
Small seal-housing and cover screws on reducing-acid pumps may be difficult to reach around adjacent fittings. B-2 socket screws provide axial tool access and corrosion resistance to compatible reducing acids. That combination is useful at compact fastening points close to process leaks and maintenance washdown.
Hastelloy B-2 Socket Head Cap ScrewsRelated material guides
Connection requirements
- Tapped-hole size, thread form, and effective engagement depth
- Head diameter, head height, and counterbore clearance required
- Reducing-acid chemistry, oxidising-contaminant exclusion, and heat-number certification
Scrubber towers & halide piping joints
Scrubber cover and duct-joint bolts can see acidic condensate on their heads and threads even when they sit outside the main process stream. C-276 hex bolts bring resistance to aggressive chloride-bearing media to those exposed fastening points. External flats give maintenance crews a readily accessible drive on removable panels and flanges.
Hastelloy C-276 Hex BoltsRelated material guides
Connection requirements
- Piping flange rating, gasket type, and required preload
- Bolt diameter, grip length, and nut/washer stack-up at installed position
- Chloride and acid exposure, and heat-number certification
Pickling tank & acid-bath hardware
B-2 socket screws can secure compact cover blocks near a compatible reducing-acid bath, with access between adjacent pipework. Assess the used liquor and cleaning liquids at the exposed screws: oxidizing contamination can invalidate a selection based on fresh acid alone.
Hastelloy B-2 Socket Head Cap ScrewsRelated material guides
Connection requirements
- Tapped-hole size, thread form, and effective engagement depth
- Head diameter, head height, and socket depth for drive engagement
- Reducing-acid chemistry, oxidising-contaminant exclusion, and heat-number certification
Acid type, concentration and chloride heat.
C-22 offers strong resistance to oxidizing process liquids, while C-276 is a useful option for reducing-acid and mixed-chemical joints. Alloy 20 targets sulfuric-acid service. Compare the actual acid, contaminants and temperature rather than treating these grades as a universal upgrade sequence.
What to specify
- Oxidising potential and halide content
- Acid concentration and temperature range
Alloy 20 and 904L offer acid-service options for transfer flanges and equipment covers; C-276 broadens the shortlist for aggressive mixed liquids. Corrosion does not rise uniformly with acid concentration, so use data for the operating concentration, temperature and impurities.
What to specify
- Sulfuric acid concentration range
- Phosphoric acid concentration range
- Operating temperature range
2205 and 2507 stud sets combine strength with chloride resistance; 625 and C-276 offer alternatives for more aggressive process liquids. Where cover gaskets relax under heat, the bolt temperature, gasket properties and initial preload determine how much clamping load remains.
What to specify
- Chloride concentration level
- Operating temperature range
- Gasket creep rate
Compare chemical-service fastener alloys.
| Material grade | Mechanical Duty / Focus | Environment | Relative cost | Popular fastener forms |
|---|---|---|---|---|
| Hastelloy C-276UNS N10276Mixed-acid resistance |
| Mixed acids and chloride-bearing process liquids | $$$$ |  Stud & nut sets |
| Hastelloy C-22UNS N06022Oxidizing media |
| Oxidizing acid mixtures and chloride-bearing process liquids | $$$$ |  Double-end studs |
| Alloy 20UNS N08020Sulfuric-acid service |
| Sulfuric-acid transfer and dosing streams | $$ |  Hex bolts |
| Inconel 625UNS N06625Corrosion resistance |
| Chloride-bearing process liquids and chemical splash | $$$ |  Flange-head bolts |
Budget guide: $ lower · $$ moderate · $$$ higher · $$$$ premium. Relative raw-material bands; dimensions, quantity, processing and inspection determine the finished-fastener quote.
Material & cost references
- Haynes International — Chemical processing alloys
- Special Metals — INCONEL alloy 625
- Carpenter Technology — 20Cb-3 (Alloy 20)
- Nickel and specialty-alloy round-bar price comparison
- Stainless-steel supplier price ranges
- 800H round-bar supplier price range
- Alloy 20 round-bar supplier price range
Cost bands group overlapping published supplier ranges for initial budgeting; they are not live BYBOLT prices. Specify the exact UNS and final condition on the order.
Bolts & studs for chemical-process connections.
Hastelloy C-276 stud & nut sets
Resist mixed-acid and chloride corrosion at removable reactor covers, with studs and mating nuts supplied together.
Hastelloy C-22 double-end studs
Resist oxidizing chemical attack at valve bonnets and pump covers; separate end threads fit the body and nut.
Alloy 20 hex bolts
Provide sulfuric-acid resistance at transfer flanges and dosing equipment without specifying a broader-duty alloy for every joint.
Inconel 625 hex flange bolts
Spread clamping load across process-equipment brackets while resisting chloride-bearing splash.
Reactor & exchanger cover kits.
Order the cover hardware together so shutdown crews can find the correct stud length, nut pattern and quantity for each vessel.
Chemical-service fastener traceability & inspection.
EN 10204 3.1 MTC, heat traceability and mechanical test results with each shipment. Add the tests your equipment specification requires.
Material identity
Match the ordered grade and material heat to the certificate, part identification and packing list.
Final condition
Link the specified processing condition and mechanical results to the finished batch; keep separate heat-treatment batches identifiable.
Drawing dimensions
Equipment tag, drawing revision and quantities for each mating part.
Chemical exposure
Include any specified corrosion test, with solution, temperature, method and acceptance criteria.
Before you order chemical-service fasteners.
Send the drawing and the service details for your connection. We can quote the specified parts, finish and inspection package together.
Get a QuoteCan you quote C-22 and C-276 alternatives against one enquiry?
Yes. Send one drawing, quantity and acceptance specification with the process and cleaning data. We can quote the options separately so the comparison includes the same nut, testing and document scope.
What should accompany a replacement pump or valve bolt?
Send the part or drawing, casing material, thread details and service chemistry. Mark any corrosion, broken section or seized threads so a dimensional replacement also addresses the reason for replacement.
Can components be packed by equipment or line number?
Yes. Include the tag and quantity for each assembly in the BOM. We can identify and pack the corresponding studs, nuts and washers together.
Send your drawing
or parts list.
Upload the drawing or BOM with its revision. We quote the material, dimensions, quantities and inspection requirements for your equipment.
Equipment tag, process and cleaning chemistry, temperature, drawing revision, grade, size and quantity…
