Made-to-order SAB bolts, nuts, studs, washers and specials for marine and industrial applications. CW301G material. Good machinability and seawater corrosion resistance; controlled low magnetic permeability. M4 to M64, metric and imperial. Material certification and batch traceability with every order.
All SAB fasteners 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
Aluminium silicon bronze for naval fasteners appears under several designations. They describe closely related alloys but are not specification-equivalent; composition limits, testing, permeability requirements 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 |
|---|---|---|
| CuAl6Si2Fe | ISO / EN symbol | Nominal composition of the naval grade — note the deliberate iron content |
| CW301G | BS EN | EN material designation for CuAl6Si2Fe; used under the applicable BS EN copper-alloy product standard |
| CA107 | BS 2874 (withdrawn) | Legacy BS designation; commonly cross-referenced to CW301G. Still common on UK and naval drawings |
| NES 834 | Royal Navy | Legacy naval material standard for wrought SAB |
| DEF STAN 02-834 Part 2 | UK MOD | Defence Standard for SAB forgings, forging stock, rods and sections; superseded NES 834 Part 2 and DGS 1044 |
| DEF STAN 02-879 Part 2 Annex D | UK MOD | Copper alloy material standard into which the 02-834 Part 2 requirements were subsequently incorporated; carries the controlled low-permeability requirement |
| C64200 | ASTM B150/B150M / UNS | US wrought aluminium silicon bronze. Frequently listed commercially alongside CA107 / SAB, but its composition (Al 6.3–7.6, Si 1.5–2.2, Fe ≤ 0.3) corresponds more closely to EN CW302G / CuAl7Si2. Not specification-equivalent to CW301G or the naval material standards |
| CW302G | BS EN 12163 | CuAl7Si2 — the general-purpose EN aluminium silicon bronze. Related, but not the naval grade |
| DGS 1044 | Director General Ships (legacy) | Pre-NES naval designation, superseded by NES 834. DGS 8453 / 8453A also appears in legacy supplier cross-reference data; the exact DGS number, suffix and issue on the drawing must be verified |
| Element | Range |
|---|---|
| Copper (Cu) | Remainder |
| Aluminium (Al) | 6.0 – 6.4 |
| Silicon (Si) | 2.0 – 2.4 |
| Iron (Fe) | 0.5 – 0.7 |
| Others | Controlled per specification |
Published composition ranges for naval-grade DEF STAN 02-834 / 02-879-type material, reproduced from UK specialist stockholder datasheets. The controlled Defence Standard governs the complete composition and impurity limits.
| Section size | Rm | Rp0.2 | A | Izod impact (BS 131-1) |
|---|---|---|---|---|
| up to 50 mm | 525 MPa min | 275 MPa min | 20% min | 33 J (above 15 mm) |
| > 50 – 100 mm | 525 MPa min | 235 MPa min | 20% min | 33 J |
| > 100 mm | 525 MPa min | 220 MPa min | 20% min | 33 J |
Density approximately 7.8 g/cm³. Ductile, predominantly alpha-phase alloy when correctly processed. Good low-temperature impact performance — specialist stockholder data describe impact properties as retained to cryogenic temperatures. Commonly classed as a spark-resistant ("non-sparking") copper alloy.
Values reproduced from specialist UK stockholder datasheets that identify them as DEF STAN 02-834 Part 2 requirements. Provided for technical guidance only; the controlled specification, issue, product form and section size stated on the order govern acceptance. Where the drawing calls for NES 834, DEF STAN 02-834, DEF STAN 02-879 or another specification, material is sourced and certified to that specification and the mill certificate shows the actual values.
The defining property. Naval-grade SAB is formulated and processed for controlled low magnetic permeability: relative magnetic permeability not exceeding 1.05 (DEF STAN 02-879 Part 2 Annex D, D.2.8; batch-tested to D.4.5). This is why it is the material for mine countermeasures vessels and other low-signature applications where NAB (μr typically 1.4–1.5) is not acceptable. Tighter permeability limits are a drawing or contract requirement and are handled at enquiry stage.
Low magnetic permeability is a test and acceptance requirement; it should not be assumed from the alloy designation alone, or from a routine material certificate that does not report the test. Where a maximum μr is contractual, state it on the enquiry so the required permeability test and certification can be specified.
Where called up by the drawing or contract, two Defence Standards may apply to a naval SAB fastener, and they cover different requirements.
Cover SAB forgings, forging stock, rods and sections: chemistry, mechanical and impact testing, and the controlled low-permeability requirement. NES 834 appears on legacy drawings and was succeeded by 02-834; those requirements were subsequently incorporated into 02-879 Annex D. Drawings may cite any of the three.
Covers procurement of Non-First Level naval fasteners (Part 3 covers First Level). Clause 8.2.5 defines the permitted manufacture of SAB fasteners: bolts, screws, studs, studbolts and nuts machined from bar with machined threads and the required post-machining stress relief; controlled hot heading of bolt and screw heads as an alternative; and washers from sheet, strip or bar with no further heat treatment. Issue 3 of 02-862 itself references DEF STAN 02-834 for SAB feedstock; where a drawing or later procurement requirement instead calls up DEF STAN 02-879 Annex D, the contractual call-up governs. Customer RFQs may refer to 02-862 informally as the "manufacture" or "post-machining" standard; the formal call-up is DEF STAN 02-862 Part 2.
What we do:
Treatment parameters and permeability test methods belong to the specifications and are not reproduced here.
SAB suits seawater fastenings for these reasons.
SAB machines more readily than NAB and suits fine-tolerance threaded parts, finer pitch threads, and complex fastener geometries that would be more difficult to achieve in NAB.
Good performance in seawater, salt spray and marine atmosphere when the alloy and manufacturing condition are correctly controlled. Suited to coastal industrial applications where long-term corrosion resistance is required.
Published DEF STAN 02-834-type bar data: Rm ≥ 525 MPa, Rp0.2 ≥ 275 MPa up to 50 mm. Good resistance to fatigue and stress corrosion cracking for high-cycle, dynamically loaded bolted joints in marine structures.
Aluminium silicon bronze has controlled low magnetic permeability — relative magnetic permeability not exceeding 1.05 (DEF STAN 02-879 Part 2 Annex D, D.2.8; batch-tested to D.4.5) — and it is specified where a low magnetic signature is required alongside corrosion resistance. Tighter permeability limits are a drawing or contract requirement and are handled at enquiry stage.
SAB is specified where machinability and corrosion resistance need to be balanced — particularly in high-precision or high-load marine applications.
SAB's machinability means it is suited to precision-threaded fasteners in hydraulic valve bodies and actuator assemblies.
Used in chemical, water treatment, and process industries where a non-ferrous, corrosion-resistant fastener is required.
SAB is used in defence applications where the drawing specifies aluminium silicon bronze rather than NAB, often for machined components and precision assemblies.
Both are bronze alloys for marine and defence fastener applications. Your drawing will specify which is required.
| SAB — Aluminium Silicon Bronze | NAB — Nickel Aluminium Bronze | |
|---|---|---|
| Alloy | CW301G | CW307G / CA104 |
| Machinability | Good — suited to fine tolerances | Good |
| Seawater corrosion resistance | Good | Excellent |
| Strength | DEF STAN 02-834-type bar — Rm ≥ 525 MPa (published) | EN 12163 R680 / R740 — Rm ≥ 680 / ≥ 740 MPa |
| Primary defence spec | NES 834 / DEF STAN 02-834 Pt 2 (superseded by 02-879 Pt 2 Annex D, Sept 2011) | DEF STAN 02-833, NES 833 |
| Magnetic permeability | Controlled low — μr not exceeding 1.05 (DEF STAN 02-879 Pt 2 Annex D, D.2.8); tighter limits by drawing or contract | ~1.4–1.5 |
| Typical applications | Low-signature, valve and high-tolerance applications | Structural and immersed naval fastenings |
Send us your drawing or SAB specification and we'll come back with a price and lead time. No minimum order quantity.
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