Phosphor Bronze
C54400 — Free-Cutting Phosphor Bronze
A leaded, free-machining phosphor bronze developed for high-speed screw-machine production of bushings, bearings and fittings.
Grade overview
C54400 adds lead (and some zinc) to a tin-phosphorus bronze base. The lead acts as a chip breaker, giving a major improvement in machinability compared with C51000 or C52100, which is why it is a staple for automatic-lathe production.
The trade-off is that the lead lowers cold formability and means the alloy is not suitable where a lead-free composition is required. Where lead-free machinable bronze is needed, alternative alloys should be discussed with the company.
Alloy family and identification
Wrought leaded phosphor bronze, UNS C54400, sometimes called “free-cutting phosphor bronze” or “B2 bronze”. Contains deliberate lead additions.
| Item | Detail |
|---|---|
| UNS designation | C54400 |
| Common name | Free-Cutting Phosphor Bronze |
| Alloy family | Phosphor Bronze |
| Type | Wrought leaded copper-tin-zinc-phosphorus alloy |
Typical composition
| Element | Nominal limit, wt % |
|---|---|
| Copper (Cu) | Remainder |
| Tin (Sn) | 3.5 – 4.5 |
| Lead (Pb) | 3.5 – 4.5 |
| Zinc (Zn) | 1.5 – 4.5 |
| Phosphorus (P) | 0.01 – 0.50 |
| Iron (Fe) | 0.10 max |
Reference data only – typical or nominal values from published specifications, not a guarantee of supplied material. Confirm against the current edition of the applicable specification, the product form and condition, and the material test certificate. Technical review by the company is required before publication or reliance.
Typical mechanical properties
Mechanical property values are intentionally not published here. They vary with specification, product form, size and temper or condition and will be added only once the governing specification and condition are confirmed. Request the applicable specification or test certificate with your inquiry.
Physical properties
Physical properties (density, thermal and electrical data) are not listed until verified against an authoritative datasheet. Contact us for current reference data.
Corrosion and wear considerations
Good atmospheric and fresh-water resistance; wear behaviour is helped by lead acting as a solid lubricant at the surface. Contains lead, so it is not appropriate for potable-water contact or other lead-restricted applications.
Machinability and fabrication
The principal reason to select this grade: it is machined at far higher speeds than unleaded phosphor bronzes. Not intended for severe cold forming. Soldering and brazing are practised.
Common industrial applications
- Automatic-lathe bushings and sleeves
- Bearings and thrust washers for light to moderate duty
- Gears, pinions and small turned components
- Valve and instrument hardware
- High-volume precision turned parts
Examples only. Suitability must be confirmed for the actual operating environment.
Available product forms
Sizes, tolerances and stock are not published and must be confirmed with the company.
Relevant products
Standards and specifications
- ASTM B139/B139M – rod, bar and shapes (coverage to be confirmed against the current edition)
Verify against the current edition and the exact product form before specifying.
Certification and inspection options
Material test certificates, chemical analysis, dimensional reports and third-party inspection can be requested with your inquiry. What can be supplied for C54400 is confirmed with the company for each order; no certificate is implied by this page.
Related grades
Frequently asked questions
Is C54400 lead-free?
No – it contains deliberate lead additions. It is not suitable where lead content is restricted.
What is C54400 used for?
Mainly machined bushings, bearings, gears and small turned parts where high-speed machining is desirable.
Need C54400 in a specific form?
Share your grade, dimensions, quantity and technical requirements with our team.