Copper Fasteners
Manufacturer
India · Mumbai
Copper Fasteners — Three Distinct Engineering Reasons
Copper and copper-alloy fasteners are specified for three distinct engineering reasons — and each reason points to a different grade: electrical conductivity (pure copper C11000/C10200), dezincification resistance in wet service (silicon bronze C65500), and high-strength marine/seawater service (aluminium bronze C63000).
Reason 1 — Electrical conductivity: Pure copper (C11000 ETP, C10200 OFE) is specified for grounding bolts, earthing hardware, bus-bar connections, transformer terminal bolts, and lightning protection system fasteners where the fastener itself must carry fault current. C10200 OFE (oxygen-free electronic grade) is specified where hydrogen embrittlement risk in high-temperature reducing atmospheres must be eliminated — vacuum tube connections, high-power RF systems, and hydrogen-atmosphere annealing furnace hardware.
Reason 2 — Marine corrosion / dezincification resistance: Silicon bronze C65500 (Cu-3%Si-1%Mn) is the preferred marine fastener alloy for below-waterline structural connections — wood-to-frame, composite-to-frame, and bronze fitting bolting on sailboats, wooden vessels, and fibre-glass hulls. Unlike brass (Cu-Zn), silicon bronze contains no zinc and therefore cannot dezincify (the selective leaching of zinc from brass alloys in stagnant seawater that destroys the fastener internally while appearing sound externally).
Reason 3 — High-strength marine/seawater: Aluminium bronze C63000 (Cu-10%Al-5%Ni-3%Fe) provides the highest strength of any copper alloy fastener (≥760 MPa UTS) with excellent seawater corrosion resistance and biofouling resistance. Specified for high-load marine structural connections where silicon bronze’s lower strength is insufficient — propeller shaft bolts, mooring equipment, subsea structural connections, and marine engineering where both strength and corrosion resistance are required simultaneously.
Copper Alloy Grade Profiles — Pure Copper to Aluminium Bronze
Each copper alloy grade serves a distinct engineering need. Select grade by primary requirement — conductivity, machinability, dezincification resistance, or high-strength marine service. All five grades available as fasteners from certified bar/rod stock.
Pure Copper ETP
OFE Copper
Free-Cutting Brass
Silicon Bronze
Aluminium Bronze
DZR Brass
Copper Fastener Types & Standards
All copper alloy fasteners from ASTM-certified bar/rod stock, PMI-verified before machining. Silicon bronze C65500 and aluminium bronze C63000 are primary stocking grades. Pure copper C11000/C10200 and brass C36000 also stocked. M4–M36.
Marine Stud Bolts
Silicon bronze C65500 and aluminium bronze C63000 fully threaded and equal-end stud bolts for marine structural connections, keel bolting, engine mounting studs, and hull fitting flanges. M6–M36, lengths to 500mm. Below-waterline service. No dezincification risk. Non-magnetic. Chemical analysis certificate per lot.
Hex Bolts
Full thread and partial thread hex bolts in pure copper, brass, silicon bronze, aluminium bronze, and DZR brass. M4–M36. Marine structural hex bolts (silicon bronze / Al bronze), plumbing equipment hex bolts (DZR brass), electrical connection hex bolts (pure copper C11000), and instrument hex bolts (C36000 free-cutting brass) for precision panel connections.
Hex Nuts
Standard hex nuts in all five copper alloy grades. M4–M36. Matched from same certified rod as hex bolts for single-alloy assembly documentation. Silicon bronze nuts for marine hull connections; aluminium bronze nuts for high-load marine; brass nuts for plumbing and instrumentation; pure copper nuts for high-conductivity grounding bus assembly.
Washers
Plain flat washers in all copper alloys. M4–M36. Silicon bronze washers for marine hull connections where the washer-nut interface must also be dezincification-resistant; copper washers for electrical bus bar bearing area distribution; aluminium bronze washers for high-load marine structural assemblies requiring matched-alloy bearing surfaces.
Socket Cap Screws
Hex socket cap screws in silicon bronze C65500 and aluminium bronze C63000. M4–M24. Confined-access marine structural connections, engine room bilge pump mounting screws, composite hull internal fixture screws, and instrument housing screws in corrosive marine environments where a non-magnetic, dezincification-resistant alloy and flush head are all required.
Grounding Hardware
Pure copper C11000 ETP grounding bolts, earthing clamps, bus bar bolting hardware, and earthing lug fasteners. For electrical substation earthing grid connections, transformer grounding bolts, lightning protection down-conductor clamps, and power generation grounding hardware where the fastener is part of the fault current path and must maintain low contact resistance over decades of service.
Custom Copper
Non-standard dimensions, countersunk heads, coach screw (lag screw) form in silicon bronze for marine timber, square neck carriage bolts in brass, and all drawing-specific copper alloy configurations. Contact sales@akbarfasteners.in with alloy, form, size, and application description.
Copper Fasteners Application Areas
Electrical grounding and conductivity, marine structural below waterline, plumbing and potable water, MRI and non-magnetic instrument installations, heritage restoration — the five distinct application niches for copper alloy fasteners.
Electrical Grounding
transformer terminal hardware
Marine / Boatbuilding
keel bolting · wooden boat
Offshore / Subsea
subsea structural connections
Plumbing & HVAC
DZR brass potable water bolts
MRI / Medical Imaging
MRI room installation hardware
Heritage & Restoration
heritage building restoration
Power Generation
OFE copper bus connections
Electronics / RF
H₂-atmosphere furnace bolts
Copper Fastener Standards Coverage
Same ISO 9001:2015 quality system as our full fastener range. PMI confirms alloy content — critical for distinguishing silicon bronze (no zinc) from brass (zinc-containing) and for confirming pure copper purity ≥99.90%.
Complete Documentation Package
ASTM B98/B150/B187
Conformance
Cu% / Alloy Confirmed
Pure Copper ≥100% IACS
Tensile · Hardness
Related Non-Ferrous Fastener Grades
Copper for conductivity and marine. Monel for high-strength seawater. Nickel for caustic. Titanium for lightweight corrosion resistance.
Monel 400 Fasteners
When copper alloy strength or corrosion resistance is insufficient for the seawater application — Monel 400’s higher Ni content provides better seawater immunity than silicon bronze at moderate temperatures, and Monel K500 (≥1000 MPa) provides the highest strength seawater fastener available.
View Monel 400 →Nickel 200 / 201 Fasteners
When the service is caustic rather than marine — pure Nickel 200/201 handles concentrated NaOH where copper alloys are marginal (copper corrodes in concentrated hot caustic). For alkaline process applications where a non-ferrous, corrosion-resistant fastener is specified beyond the copper alloy range.
View Nickel Range →Hastelloy C276 Fasteners
When the chemical environment exceeds copper alloy corrosion limits — acidic seawater, high-temperature sulphides, strong oxidising acids. Hastelloy C276’s Ni-Cr-Mo chemistry provides broader corrosion resistance than any copper alloy in aggressive chemical service.
View C276 →SS 316L Fasteners
When corrosion resistance is required but magnetism is acceptable — SS 316L provides seawater and chemical resistance with higher strength than silicon bronze at lower cost than aluminium bronze. For marine applications where PRE≈24 is sufficient and copper’s non-magnetic property is not required.
View SS Range →Need Copper Alloy
Fasteners?
Alloy (ETP/OFE/brass/Si-bronze/Al-bronze) · product form · size · application. Akbar Fasteners Pvt. Ltd. responds within 24 hours.
Export: +91 8696 32 4646 · Support: +91 800 9315 333 · export@akbarfasteners.in