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
Acid exchanger covers may leave concentrated residue around the outer bolt holes after a small leak dries. C-276 washers put a corrosion-resistant surface under the nuts in that exposed area. A flat, adequately thick washer supports the nut across the machined seat and can be replaced when the cover is serviced.
Hastelloy C-276 Flat WashersRelated material guides
Connection requirements
- Acid composition and operating temperature
- Nut footprint and cover spotface
- Thickness, flatness and edge finish
Chemical transfer pump casings
A chemical-pump casing needs a sound bearing face when its cover bolts are retightened after seal or impeller work. C-276 washers suit pumps handling aggressive acids where drips also reach the external hardware. Smooth, burr-free faces avoid cutting into the casing seat as the fastener is tightened.
Hastelloy C-276 Flat WashersRelated material guides
Connection requirements
- Pumped fluid and external leakage exposure
- Casing seat width
- Bore, face finish and assembly load
Scrubber towers & halide piping joints
Scrubber access panels and duct flanges encounter wet condensate rather than the steady bulk chemistry shown on a process sheet. C-276 washers are useful beneath fasteners where acidic halide deposits collect. On slotted panel supports, their outside diameter must span the slot and their thickness must carry the local bending load.
Hastelloy C-276 Flat WashersRelated material guides
Connection requirements
- Condensate and cleaning chemistry
- Slot width and unsupported span
- Panel thickness and washer thickness
Pickling tank & acid-bath hardware
C-22 studs can secure pickling-equipment covers and pipe connections exposed to acid splash and contaminated fumes. They are worth considering when the chemistry includes oxidizing species or varies during use. Fixed studs also simplify positioning of removable covers around tanks and acid-handling auxiliaries.
Hastelloy C-22 Stud BoltsRelated material guides
Connection requirements
- Hardware thickness, load, and required preload
- Stud diameter, overall length, and nut engagement at each end
- Exposure chemistry, cycling duty, 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…
