Made-to-order NAB bolts, nuts, studs, washers and specials for seawater, naval, and defence applications. Available to DEF STAN 02-833, NES 833 and customer drawings where specified. M4 to M64 metric and imperial. Material certification and batch traceability with every order.
Every fastener sourced to order against your drawing or specification. No minimum order quantity.
ISO 4014 / ISO 4017, BS 3692; legacy DIN 931 / 933.
M4–M64
ISO 4032 regular, ISO 4035 thin; legacy DIN 934. All-metal locking forms to ISO 7042 / 7719 / 10513 within each standard's own size range; other sizes to drawing and qualification review.
M4–M64
BS 4439 studs, BS 4882 studbolt forms, engineering studs, DIN 976 threaded bar.
M8–M52 subject to review
ISO 7089 / 7090 normal series; legacy BS 4320 A / B / C where specified; large series to ISO 7093-1 or legacy DIN 9021; spring and specials to drawing.
M4–M64
ISO 4762 cap, DIN 7984 low head, ISO 10642 CSK, ISO 4026–4029 grub.
M3–M36 overall, each form within its standard's range
Slotted countersunk, pan and cheese to ISO 2009 / 1580 / 1207 or BS 4183.
M2–M10
UNC, UNF, BSW, BSF and BA for legacy and US-origin equipment.
1/4"–2"
Specials, obsolete drawings and one-offs — subject to specification and manufacturing review.
Send your drawing
Nickel aluminium bronze appears on drawings under several national and defence designations. They describe closely related alloys, but they are not specification-equivalent: composition limits, mechanical requirements, inspection and heat treatment differ between them. Material is supplied to the exact specification, part and issue stated on the drawing or purchase order.
| Designation | System | Notes |
|---|---|---|
| CuAl10Ni5Fe4 | ISO / EN symbol | Nominal composition |
| CW307G | BS EN 12163 / 12165 / 12167 / 12420 (2024 editions) | European material designation used for rod, bar, profile, forging stock and forgings under the applicable EN product standard |
| CA104 | BS 2874 (withdrawn) | Legacy BS wrought NAB designation; commonly cross-referenced to CW307G. Still common on UK and naval drawings |
| NES 833 | Royal Navy | Legacy naval material standard for wrought NAB |
| DEF STAN 02-833 Part 2 | UK MOD | Defence Standard for NAB forgings, forging stock, rods and sections; superseded NES 833 Part 2 and DGS 1043. Adds requirements beyond the EN alloy (chemistry, testing, size-dependent heat treatment) |
| C63000 / C63200 | ASTM B150/B150M / UNS | US wrought NAB grades. Broadly comparable to CW307G / CA104 but with different composition limits; not specification-equivalent |
| C95800 | ASTM B148 / UNS | US cast NAB — see note below |
| AB2 | BS 1400 (withdrawn, replaced by BS EN 1982) | Legacy UK cast NAB grade; cross-referenced in the EN system as CC333G (CuAl10Fe5Ni5-C) and commonly compared with ASTM C95500. C95800 is another marine cast NAB grade but is not specification-equivalent to AB2 |
| 2.0966 | Werkstoff-Nr. | Legacy German material number for CuAl10Ni5Fe4 (former DIN 17665 / 17672) |
| Element | Min | Max |
|---|---|---|
| Copper (Cu) | Remainder | — |
| Aluminium (Al) | 8.5 | 11.0 |
| Nickel (Ni) | 4.0 | 6.0 |
| Iron (Fe) | 3.0 | 5.0 |
| Manganese (Mn) | — | 1.0 |
| Zinc (Zn) | — | 0.4 |
| Silicon (Si) | — | 0.2 |
| Tin (Sn) | — | 0.1 |
| Lead (Pb) | — | 0.05 |
| Others total | — | 0.2 |
EN 12163 specifies tensile properties (R conditions) and hardness (H conditions) as alternatives. A bar is ordered to one or the other.
| Condition | Nominal diameter or width across-flats (d/w) | Rm | Rp0.2 | A | Hardness |
|---|---|---|---|---|---|
| R680 | 10 < d/w ≤ 120 mm | ≥ 680 MPa | ≥ 320 MPa | ≥ 10% | — |
| R740 | 10 < d/w ≤ 80 mm | ≥ 740 MPa | ≥ 400 MPa | ≥ 8% | — |
| H170 | 10 < d/w ≤ 120 mm | — | — | — | 170–210 HBW |
| H200 | 10 < d/w ≤ 80 mm | — | — | — | ≥ 200 HBW |
Density approximately 7.6 g/cm³.
These are the published room-temperature limits for the alloy under BS EN 12163:2024. DEF STAN 02-833 imposes its own chemistry, testing and heat treatment requirements, which are not reproduced here. Where the drawing calls for NES 833, DEF STAN 02-833 or another specification, material is sourced and certified to that specification and the mill certificate shows the actual values.
Where called up by the drawing or contract, two Defence Standards may apply to a naval NAB fastener, and they cover different requirements.
Covers NAB forgings, forging stock, rods and sections. Governs chemistry, mechanical testing and, where applicable, heat treatment of the feedstock to control microstructure — the phases associated with selective phase corrosion in seawater. Superseded NES 833 Part 2, which still appears on legacy drawings.
Covers procurement of Non-First Level naval fasteners (Part 3 covers First Level). Clause 8.2.4 defines the manufacturing and subsequent treatment requirements for NAB fasteners: stress relief for machined studs, studbolts, nuts, bolts and screws; a separate heat treatment route for hot-headed bolts and screws; and no further heat treatment for washers. The standard also calls up dimensional standards for common fastener forms.
What we do:
Treatment parameters belong to the specifications and are not reproduced here.
NAB suits seawater fastenings for these reasons.
NAB provides very good resistance to seawater corrosion when the alloy, microstructure and manufacturing condition are correctly controlled. As with other marine alloys, localised, crevice, galvanic and selective-phase corrosion can occur under adverse conditions, which is why the naval specifications control microstructure and heat treatment.
Relative magnetic permeability typically around 1.4–1.5 — lower than steel, but not a low-signature material. Where a permeability limit applies, specify SAB.
EN 12163 R680 and R740 conditions (Rm ≥ 680 / ≥ 740 MPa). NAB combines corrosion resistance with the mechanical strength needed for high-load fastener applications in naval structures.
NAB fasteners are specified wherever seawater corrosion, biofouling, or magnetic signature are a concern.
The naval fastener material under DEF STAN 02-833 Part 2 and, before it, NES 833. Supplied into Portsmouth-based naval refit programmes.
Both are copper-aluminium alloys used in marine fastener applications. Your drawing will specify which is required.
| NAB — Nickel Aluminium Bronze | SAB — Aluminium Silicon Bronze | |
|---|---|---|
| Alloy | CW307G / CA104 | CW301G |
| Seawater corrosion resistance | Excellent | Good |
| Strength | EN 12163 R680 / R740 — Rm ≥ 680 / ≥ 740 MPa | DEF STAN 02-834-type bar — Rm ≥ 525 MPa (published) |
| Machinability | Good | Better — tighter tolerances |
| Magnetic permeability | ~1.4–1.5 | Controlled low — μr not exceeding 1.05 (DEF STAN 02-879 Pt 2 Annex D, D.2.8); tighter limits by drawing or contract |
| Primary spec | DEF STAN 02-833, NES 833 Route: DEF STAN 02-862 Pt 2 Para 8.2.4 | NES 834 / DEF STAN 02-834 Pt 2 (superseded by 02-879 Pt 2 Annex D, Sept 2011) |
| Typical applications | Structural and immersed naval fastenings | Low-signature, valve and high-tolerance applications |
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