Made-to-order SAB hex bolts, nuts and stud bolts for marine, offshore, and industrial applications. CW118C material. High machinability with excellent corrosion resistance. M4 to M64, metric and imperial. Full material certification as standard.
Silicon aluminium bronze (SAB) is a copper-based alloy containing aluminium and silicon as the primary alloying elements. It combines good corrosion resistance in seawater and marine environments with significantly better machinability than nickel aluminium bronze — making it the preferred choice where tight tolerances, fine thread forms, or complex fastener geometries are required.
SAB offers excellent fatigue strength and resistance to stress corrosion cracking, which makes it well-suited to high-load bolted connections in seawater systems. It performs reliably in offshore, marine, and industrial applications where a corrosion-resistant material is required but the extreme seawater immersion conditions that mandate NAB are not present.
Unlike NAB, SAB is not typically specified under DEF STAN 02-833 or NES 833 — those standards are specific to nickel aluminium bronze. SAB fasteners are usually specified by alloy designation (CW118C) or by drawing requirement. If your drawing calls out silicon aluminium bronze, silicon bronze, CW118C, or NES 834, we can supply to it. Where heat treatment is required for SAB, this is to DEF STAN 02-862 Part 2 Para 8.2.5, supplied with full time-temperature records.
SAB is chosen when machinability and tight tolerances matter as much as corrosion resistance.
SAB machines significantly more cleanly than NAB, enabling tighter thread tolerances, finer pitch threads, and complex fastener geometries that would be more difficult to achieve in NAB.
Excellent performance in seawater, salt spray, and marine atmosphere. Well-suited to offshore and coastal industrial applications where long-term corrosion resistance is required.
Good resistance to fatigue and stress corrosion cracking makes SAB a reliable choice for high-cycle, dynamically loaded bolted joints in marine and offshore structures.
Like NAB, silicon aluminium bronze is non-magnetic — suitable for applications where magnetic neutrality is required alongside corrosion resistance.
All SAB fasteners sourced to order against your drawing or specification. No minimum order quantity.
Full and part thread to ISO 4014, DIN 933, and customer drawings. Material cert to CW118C / BS 2874 included.
M4 to M64 — larger on request
Standard and thick hex nuts to ISO 4032 / DIN 934. Matched to bolt order or supplied separately against drawing.
M4 to M64 — all thread pitches
Double-ended studs for flanges, hydraulic assemblies, and valve bolting. Supplied to your specified thread form and length.
M8 to M52 — any length
Countersunk, pan head, and cheese head machine screws to DIN 963, DIN 85, DIN 84, and customer drawings. Material cert to CW118C / BS 2874 included.
M4 to M12 — larger on request
Socket heads, countersunk, fine thread, UNC/UNF imperial, left-hand thread. SAB's machinability makes complex forms more achievable.
Metric & imperial — send your drawing
SAB is specified where machinability and corrosion resistance need to be balanced — particularly in high-precision or high-load marine applications.
SAB's machinability makes it the preferred choice for precision-threaded fasteners in hydraulic valve bodies and actuator assemblies.
Good seawater corrosion resistance makes SAB suitable for offshore platform and marine vessel applications where NAB is not specified.
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 silicon aluminium 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 — Silicon Aluminium Bronze | NAB — Nickel Aluminium Bronze | |
|---|---|---|
| Alloy | CW118C | CW307G / C95800 |
| Machinability | Excellent — tight tolerances | Good |
| Seawater corrosion resistance | Good | Outstanding |
| Primary defence spec | Customer drawing / BS 2874 | DEF STAN 02-833, NES 833 |
| Non-magnetic | Yes | Yes (heat treated) |
| Best for | High-tolerance, hydraulic, valve, precision | Naval seawater, defence, minesweepers |
Send us your drawing or SAB specification and we'll come back with a price and lead time. No minimum order quantity.