Monel 400
Stud Bolts
UNS N04400
Monel 400 Stud Bolts — When to Specify
Monel 400 (UNS N04400) is the annealed nickel-copper alloy — 63–70% Ni with copper as balance — that delivers permanent seawater and chloride immunity without the age-hardening heat treatment required by Monel K500. For ASME B16.5 flanged pressure joints in seawater services, HF acid units, desalination plants, and marine heat exchangers where the design bolt load does not require age-hardened strength, Monel 400 stud bolts are the correct and cost-effective specification.
The decisive advantage over 316L stainless stud bolts in seawater flanged joints: Monel 400 shows near-zero corrosion in seawater at all velocities and temperatures, permanent immunity in tidal and splash zones, and no susceptibility to chloride stress corrosion cracking. A 316L stud bolt in the same seawater flange will pit, crevice-corrode at the thread-nut interface, and seize within months to years depending on exposure. Monel 400 studs in the same service routinely last decades without visible corrosion or thread damage.
For applications requiring ≥1000 MPa tensile strength — subsea wellhead bolting, FPSO riser clamps, and Class 1500/2500 high-pressure joints — step up to our Monel K500 stud bolts. For HCl and reducing acid service where Monel is not sufficient, see our Hastelloy B3 stud bolts.
| Element | Min % | Max % | Typical |
|---|---|---|---|
| Nickel + Cobalt | 63.0 | — | ~67% |
| Copper (Cu) | — | Balance | ~31% |
| Iron (Fe) | — | 2.5 | ~1.5% |
| Manganese (Mn) | — | 2.0 | ~1.0% |
| Carbon (C) | — | 0.30 | <0.15% |
| Silicon (Si) | — | 0.50 | <0.3% |
| Sulfur (S) | — | 0.024 | — |
Monel 400 Stud Bolt Configurations
All configurations machined from ASTM B164 certified UNS N04400 annealed bar. Custom end lengths, thread engagement, and ASME PCC-1 torque calculations available on request.
Fully Threaded Stud
Thread runs the complete length — standard for ASME B16.5 raised-face and ring-joint flanged pressure joints. Both ends receive a Monel 400 heavy hex nut. Class 150–2500. The most common Monel 400 stud bolt configuration for marine and offshore seawater flange service.
Equal-End Stud Bolt
Threaded ends of equal length with a plain centre shank. Plain shank confirms correct nut engagement length visually during tightening — essential for high-integrity flanged joints in HF acid units and seawater desalination plants where over- or under-engagement is a safety issue.
Unequal-End Stud
One end screws permanently into a tapped valve body or equipment nozzle; the nut is applied to the other. Thread engagement per ASME PCC-1 / ASME B1.1. Commonly used in seawater-exposed marine valve bonnets and pump casing covers where permanent thread engagement on one side is required.
Medium-Pressure Stud
Standard stud bolt sets for Class 300 and Class 600 flanged joints in seawater cooling systems, marine heat exchangers, and desalination plant brine circuits. Full ASME B16.5 dimensional compliance. M20–M64. Supply with matched Monel 400 heavy hex nuts from same B164 heat.
Long Shank / Thermal Stud
Extended plain shank for applications requiring thermal expansion accommodation or access clearance. Used in marine heat exchanger covers with large face separations and in seawater service where differential thermal expansion must be absorbed by the unthreaded shank length.
Custom / Non-Standard
Left-hand thread, inch UNC/UNF, non-standard diameters, lengths to 3,000mm, and drawing-specific configurations. Monel 400 stud bolts for HVAC seawater cooling, ship propeller shaft assemblies, and bespoke offshore structural connections. Send drawing to sales@akbarfasteners.in.
ASME B16.5 Monel 400 Stud Bolt Lengths — Class 150 to 2500
Standard lengths per ASME B16.5 / ASME B18.31.2 including two Monel 400 heavy hex nuts. All in mm. Compare with our Monel K500 stud bolt table for higher-strength applications. Custom lengths to 3,000mm.
| Dia. (M) | Thread Pitch | Class 150 (mm) | Class 300 (mm) | Class 600 (mm) | Class 900 (mm) | Class 1500 (mm) | Class 2500 (mm) |
|---|---|---|---|---|---|---|---|
| METRIC — UNS N04400 · ASTM B164 · ANNEALED | |||||||
| M12 | 1.75 mm | 90 | 100 | 115 | 125 | 140 | — |
| M16 | 2.0 mm | 100 | 110 | 125 | 140 | 160 | — |
| M20 | 2.5 mm | 110 | 125 | 140 | 160 | 185 | 215 |
| M24 | 3.0 mm | 125 | 140 | 160 | 180 | 210 | 245 |
| M30 | 3.5 mm | 145 | 165 | 190 | 215 | 255 | 300 |
| M36 | 4.0 mm | 170 | 195 | 225 | 260 | 305 | 360 |
| M42 | 4.5 mm | 195 | 225 | 265 | 305 | 355 | 420 |
| M48 | 5.0 mm | 220 | 260 | 300 | 345 | 400 | 475 |
| M56 | 5.5 mm | — | 290 | 340 | 390 | 455 | 545 |
| M64 | 6.0 mm | — | 325 | 380 | 440 | 515 | 615 |
| M72 | 6.0 mm | — | 360 | 425 | 490 | 575 | — |
| M80 – M100 | 6.0 mm | — | — | Custom | Custom | Custom | — |
* Lengths indicative per ASME B16.5 including two heavy hex nuts. Confirmed on order against flange dimensions. Inch UNC/UNF available. Custom to 3,000mm — sales@akbarfasteners.in
Standards We Manufacture & Test To
Same heat-traceability and quality process as our Hastelloy B3 stud bolts — full MTC, COC, PMI, and NABL-accredited test reports on every order.
Industry Applications
Permanent seawater immunity, HF acid resistance, and marine atmospheric corrosion resistance — in flanged pressure joints where 316L fails and K500 strength is not required.
Seawater Systems
seawater pump nozzles
Marine & Offshore
shipboard piping
Desalination Plants
RO pressure vessel nozzles
HF Alkylation Units
alkylation reactor nozzles
Oil & Gas
cooling water nozzles
Naval & Shipbuilding
bilge pump nozzles
Power Generation
condenser nozzle joints
Chemical Processing
brine handling joints
Complete Documentation Package
Heat & Lot Traceable
Conformance
100% Lots Verified
Tensile · Hardness
TÜV · BV · Lloyds
Related Monel 400 & Alloy Components
Matched material throughout the joint — nuts and washers from the same certified UNS N04400 heat. Or choose the right alloy for a different service environment.
Monel 400 Fasteners
Full Monel 400 range — hex bolts, hex nuts, washers, socket screws — all annealed, all from the same certified heat as these stud bolts.
View Page →Monel 400 Washers
Flat and spring washers in Monel 400 to DIN 125/127. M5–M100. Complete the flanged joint with matched material washers from same heat — no galvanic couple.
View Page →Monel K500 Stud Bolts
Age-hardened version — ≥1000 MPa UTS. For Class 1500/2500 high-pressure flanges and subsea bolting where Monel 400 strength is insufficient.
View Page →Hastelloy B3 Stud Bolts
For HCl and reducing acid service where Monel 400 is insufficient. Near-zero corrosion in HCl at all concentrations. Class 150–2500, M12–M100.
View Page →Need Monel 400
Stud Bolts Now?
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