Corrosion-resistant fasteners for Water Treatment & Desalination.
High-strength duplex studs and corrosion-resistant flange sets for seawater pumps, concentrate lines and treatment equipment.
Which fasteners fit your water-treatment and desalination applications?
BYBOLT supplies Super Duplex 2507 stud bolts and stud & nut sets for high-pressure seawater pumps and flanges. Inconel 625 stud & nut sets add corrosion resistance for demanding brine connections; Duplex 2205 hex bolts offer strength for less aggressive treatment-water equipment. Order by stream and equipment tag to keep the correct alloy with each connection.
Fasteners for desalination & water-treatment equipment.
SWRO high-pressure membrane vessels
On SWRO assemblies with bolted end hardware or external supports, 2507 studs carry the connection load in saline service. Super duplex strength is useful within the available bolt pattern, while chloride resistance addresses brine around the exposed threads. The end-plate and support layouts determine the stud lengths and nut stack.
Super Duplex 2507 Stud BoltsRelated material guides
Connection requirements
- Vessel end-retention drawing
- Design load and end-plate thickness
- Stud length and nut arrangement
Brine booster & high-pressure pumps
Brine booster cover nuts remain exposed to concentrated salt deposits after small leaks or washdown. 2507 heavy hex nuts are useful where the pump specification selects super duplex bolting. Nut height must provide full thread engagement while retaining enough stud projection for the selected tightening and inspection method.
Super Duplex 2507 Heavy Hex NutsRelated material guides
Connection requirements
- Brine and cleaning exposure
- Nut height and stud projection
- Thread fit and proof-load requirement
Energy recovery devices (ERDs)
2507 studs can serve bolted covers and flanges on energy-recovery equipment specified for super duplex fastening. Their strength and chloride resistance are useful where compact pressure housings leave a limited fastening envelope. A tapped-stud arrangement can retain the studs during servicing; through-flange connections use their own nut and engagement layout.
Super Duplex 2507 Stud BoltsRelated material guides
Connection requirements
- Housing pressure and cover load
- Seawater or brine temperature
- Nut access and stud engagement
Seawater intake screens & gates
Intake-screen and gate brackets often use slotted holes for alignment. 2507 washers can bridge these slots in seawater exposure while carrying the nut pressure onto the support. The unsupported span sets the required thickness, and the washer outline must leave enough edge distance on the bracket.
Super Duplex 2507 Flat WashersConnection requirements
- Slot width and mounting load
- Washer outline and thickness
- Support metal and immersed exposure
Chemical dosing & chlorination skids
Chemical dosing skids combine small pumps and valve blocks in crowded layouts. 825 socket screws can retain removable housings exposed to compatible sulfuric-acid dosing solutions. The head needs a clean, fully supported seat; placing the recess away from a drip path reduces chemical accumulation in the drive.
Incoloy 825 Socket Head Cap ScrewsRelated material guides
Connection requirements
- Dosing chemical and concentration
- Head-seat dimensions
- Blind-hole engagement and screw length
Thermal desalination (MED/MSF) evaporators
Thermal-desalination equipment has saline covers and auxiliary connections that must be opened for cleaning. S32760 studs can serve those joints where temperature and brine chemistry fall within the selected super duplex duty. Their removable nuts simplify cover work, while the complete flange stack determines the stud length.
Super Duplex S32760 Stud BoltsConnection requirements
- Brine temperature and chemistry
- Cover, gasket and nut stack
- Required mechanical properties at service temperature
Salinity, oxidants and cyclic pressure.
2205 offers strength for less aggressive treatment-water joints; 2507 and SMO 254 add pitting resistance for demanding chloride exposure. Select seawater and concentrate-line fasteners using temperature, deposits and crevice conditions, including shutdown periods.
What to specify
- Chloride concentration
- Brine concentration ratio
- Service temperature range
Titanium Grade 2 is an option for wet hypochlorite service where chemistry and temperature support its protective film. C-276 is another candidate for some mixed treatment liquids. Separate directly wetted dosing joints from external skid bolts exposed only to occasional splash.
What to specify
- Free chlorine concentration
- Oxidant exposure duration
- Cleaning chemical pH range
2507 and Zeron 100 combine high strength with chloride resistance for high-pressure RO connections. Fatigue life and retained preload also depend on thread geometry, assembly preload and the pressure cycle; an alloy change alone does not solve joint loosening.
What to specify
- Pressure cycle count
- Peak operating pressure
- Preload retention requirement
Compare water-service fastener alloys.
| Material grade | Mechanical Duty / Focus | Environment | Relative cost | Popular fastener forms |
|---|---|---|---|---|
| Super Duplex 2507UNS S32750High strength |
| Seawater feed and concentrate circuits | $$ |  Stud bolts |
| Duplex 2205UNS S32205 / S31803Duplex stainless |
| Brackish water and chloride-bearing pretreatment circuits | $$ |  Hex bolts |
| Inconel 625UNS N06625Corrosion resistance |
| Warm chloride-rich brines and evaporator auxiliaries | $$$ |  Stud & nut sets |
| 316L stainless steelUNS S31603Low-carbon stainless |
| Low-chloride permeate and treated-water circuits | $ |  Stud bolts |
Budget guide: $ lower · $$ moderate · $$$ higher · $$$$ premium. Relative raw-material bands; dimensions, quantity, processing and inspection determine the finished-fastener quote.
Material & cost references
- Nickel Institute — Alloys in water and desalination
- Alleima — SAF 2507 material data
- Special Metals — INCONEL alloy 625
- Alleima — SAF 2205 material data
- 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.
2205 may be ordered as S32205 or S31803; identify the required UNS on the order.
Pump-cover studs & water-system flange bolts.
Super Duplex 2507 stud bolts
Carry high pump-cover loads while resisting chloride corrosion in seawater feed service.
Super Duplex 2507 stud & nut sets
Keep high-strength studs and matching nuts together for seawater-feed and concentrate flanges.
Inconel 625 stud & nut sets
Resist pitting and crevice attack at brine connections where warm salt water collects beneath nuts.
Duplex 2205 hex bolts
Provide a strong, cost-conscious option for brackish-water pretreatment equipment where 2507 is unnecessary.
Desalination pump & flange kits.
Keep each stream’s bolting separate, with complete mating sets packed to the pump or flange schedule.
Water-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
Line class, flange schedule and quantities per joint.
Duplex inspection
State any required metallography or corrosion testing, the sampling plan and the production lot it covers.
Before you order desalination 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 one bolting list cover the whole desalination skid?
Yes. Keep line or equipment tags, stream names and material specifications on separate BOM lines. We can quote and pack the corresponding bolting sets by connection.
What should I send to compare 2205 and 2507?
Include chloride or salinity, maximum joint temperature, oxidizing treatment, shutdown conditions and required strength. Add the existing material specification and any corrosion-test acceptance.
What inspection should be specified for duplex fasteners?
State the grade and condition, mechanical acceptance and any required metallography or corrosion testing. Identify sampling and the lot to which each result must apply.
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.
Stream/line tag, chloride or salinity, temperature, treatment and cleaning, flange/pump drawing, grade and quantity…
