High-temperature fasteners for Turbines & Power Plants.
High-strength casing studs, compact flange bolts and hot-service replacements for turbine and power-plant maintenance.
Which fasteners fit your turbine and power-plant applications?
BYBOLT supplies Inconel 718 stud bolts for high-strength turbine-casing joints and A-286 12-point flange bolts where wrench access is tight. Inconel 718 double-end studs secure steam-valve bonnets, while Incoloy 800H stud bolts resist creep in sustained hot service. Order to your equipment drawing, with the required heat treatment and mating nuts.
Fasteners for turbines & power-plant equipment.
Gas & steam turbine casing joints
A high-strength turbine casing stud needs a nut whose proof load suits the stud, as well as enough bearing area on the casing. Inconel 718 heavy hex nuts provide a substantial nut pattern in a precipitation-hardened alloy. Their wider flats also support robust socket engagement during controlled assembly.
Inconel 718 Heavy Hex NutsRelated material guides
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Temperature range, cycling duty, and age-hardened condition certification
High-pressure steam valve bonnets
Steam-valve bonnet nuts carry the stud load above the pressure cover. Inconel 718 heavy hex nuts suit assemblies specifying high-strength hot-service bolting, with the nut heat treatment and proof load matched to the stud. The larger pattern is helpful where the bonnet spotface provides adequate bearing space.
Inconel 718 Heavy Hex NutsRelated material guides
Connection requirements
- Mating stud diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Temperature range, cycling duty, and age-hardened condition certification
Exhaust manifolds & expansion bellows
At an exhaust flange or bellows support, Inconel 718 hex bolts carry pipework loads through a limited bolt pattern. Precipitation-hardened strength is useful where the fasteners remain hot and there is little room to increase their diameter. Accessible heads allow the complete bolts to be withdrawn when the flange or support is dismantled.
Inconel 718 Hex BoltsRelated material guides
Connection requirements
- Manifold flange thickness, gasket type, and required preload
- Bolt diameter, grip length, and nut/washer stack-up at installed position
- Temperature range, vibration duty, and age-hardened condition certification
Boiler tube hangers & superheaters
On boiler hanger and superheater support rods, X-750 nuts can form part of a sustained hot-load attachment. The regular hex pattern fits compact brackets and allows position adjustment on threaded ends. The relevant advantage is the alloy's hot mechanical behaviour in the specified treatment condition.
Inconel X-750 Hex NutsRelated material guides
Connection requirements
- Mating bolt diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Temperature range, cycling duty, and heat-number certification
Flue-gas desulfurization (FGD) ducts
At FGD duct covers and inspection doors, fasteners may see acidic condensate concentrated beneath deposits. Inconel 625 hex bolts provide chloride-corrosion resistance at the head, shank and thread. The removable bolt form suits panels opened for cleaning, where corrosion of the fastening points would complicate maintenance.
Inconel 625 Hex BoltsRelated material guides
Connection requirements
- Duct joint thickness, 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
Generator & rotor tie-bolt assemblies
Rotor tie-bolt nuts transfer a large axial load into the end of the assembly. A heavy hex 718 nut offers a strong threaded section and a generous bearing footprint where the rotor design allows it. The drawing's balance, seating and locking details remain essential parts of this particular component.
Inconel 718 Heavy Hex NutsRelated material guides
Connection requirements
- Mating tie-bolt diameter, thread form, and thread class
- Nut height, width across flats, and bearing-face condition required
- Load, cycling duty, and age-hardened condition certification
Temperature, expansion, and condensate corrosion.
B16, A-286, 718 and Waspaloy serve different hot-bolting duties. For a casing joint, compare temperature-specific relaxation and creep data in the final heat-treated condition; room-temperature strength does not establish retained clamp load.
What to specify
- Design service temperature band
- Required clamp-load retention criterion
- Creep strength grade designation
Casing and fastener expansion can either increase or reduce clamp load during startup. Choose A-286 or 718 using the casing alloy, grip length and temperature distribution, then set preload for the complete joint.
What to specify
- Flange-to-fastener expansion differential
- Operating thermal cycle range
- Gasket seating stress requirement
C-276 and 625 offer corrosion-resistant options for fasteners exposed to acidic FGD condensate. 2507 remains an option where condensate chemistry and temperature support it; distinguish external duct attachments from continuously wetted or deposit-covered threads.
What to specify
- Condensate chloride exposure classification
- Wet-versus-dry service zone designation
- Alloy corrosion resistance grade
Compare power-plant fastener alloys.
| Material grade | Mechanical Duty / Focus | Environment | Relative cost | Popular fastener forms |
|---|---|---|---|---|
| Inconel 718UNS N07718Age hardened |
| Hot casing joints with startup and shutdown cycles | $$$ |  Stud bolts |
| A-286UNS S66286Hot strength |
| Hot casing and steam-system connections | $$ |  12-point bolts |
| Incoloy 800HUNS N08810Creep resistance |
| Hot exhaust and heat-recovery equipment with long dwell times | $$$ |  Stud bolts |
| Inconel 625UNS N06625Corrosion resistance |
| Seawater-cooled auxiliaries and corrosive condensate exposure | $$$ |  Stud bolts |
Budget guide: $ lower · $$ moderate · $$$ higher · $$$$ premium. Relative raw-material bands; dimensions, quantity, processing and inspection determine the finished-fastener quote.
Material & cost references
- Special Metals — INCONEL alloy 718
- Special Metals — High-performance alloy reference guide
- Special Metals — INCOLOY alloys 800H and 800HT
- Special Metals — INCONEL alloy 625
- 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.
Turbine casing bolts & steam-valve studs.
Inconel 718 stud bolts
Provide high-strength clamping at hot turbine casings, with grip and thread lengths matched to the joint.
A-286 12-point flange bolts
Fit crowded casing joints while retaining elevated-temperature strength and an integral bearing flange.
Inconel 718 double-end studs
Secure hot steam-valve bonnets with separate thread lengths for body engagement and mating nuts.
Incoloy 800H stud bolts
Resist creep in heat-recovery and exhaust connections that stay hot and loaded for long periods.
Turbine & steam-valve maintenance kits.
Group the hardware for each casing or valve before the outage, including the short bolts and mating nuts that are easy to miss.
Power-plant 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
OEM part number, drawing revision and installation location.
OEM acceptance
Include hot tensile, creep, relaxation or witness requirements from the controlled equipment specification.
Before you order power-plant 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 an OEM replacement from a part number?
Send the part number with the controlled drawing or dimensional specification, alloy condition and quantity. Include any inspection requirements attached to the OEM purchase specification.
Can room-temperature test results cover a hot joint?
Room-temperature tests document those measured properties. If the design requires hot tensile, creep or relaxation evidence, include the test temperature, duration and acceptance criteria in the enquiry.
Can nuts and studs be supplied as matched sets?
Yes. Specify both components, including their material conditions and nut pattern. Sets can be identified by casing or valve tag and linked to their material and finished-batch records.
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.
OEM drawing/part number, casing or valve tag, alloy condition, metal temperature, grip/thread dimensions and outage quantity…
