Phosphor Bronze
C51000 — Phosphor Bronze A (5% Tin)
A general-purpose wrought phosphor bronze with about 5% tin, valued for its combination of strength, fatigue resistance, formability and corrosion resistance.
Grade overview
C51000 is the most widely specified of the wrought phosphor bronzes. Tin strengthens the copper matrix and a small residual phosphorus content (retained from deoxidation) improves strength and wear behaviour. It is commonly supplied as rod, bar, plate, sheet and strip, and can be cold worked to higher strength tempers.
Compared with higher-tin phosphor bronzes such as C52100, C51000 offers better cold formability and bendability, while giving up some hardness and wear resistance. Compared with the free-cutting grade C54400, it is not leaded, so it is normally selected where formability, spring behaviour or lead-free composition matter more than high-speed machining.
Alloy family and identification
Wrought copper-tin-phosphorus alloy. Designated UNS C51000; often referred to by trade terms such as “phosphor bronze A” or “5% phosphor bronze”. Always identify by UNS number and product specification rather than by trade name alone.
| Item | Detail |
|---|---|
| UNS designation | C51000 |
| Common name | Phosphor Bronze A (5% Tin) |
| Alloy family | Phosphor Bronze |
| Type | Wrought copper-tin-phosphorus alloy |
Typical composition
| Element | Nominal limit, wt % |
|---|---|
| Copper (Cu) | Remainder |
| Tin (Sn) | 4.2 – 5.8 |
| Phosphorus (P) | 0.03 – 0.35 |
| Zinc (Zn) | 0.30 max |
| Iron (Fe) | 0.10 max |
| Lead (Pb) | 0.05 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 resistance to atmospheric corrosion and to many fresh-water and mildly corrosive industrial environments. Like other copper alloys it is attacked by ammonia-bearing and strongly oxidising media. Wear performance is moderate; for heavy bearing duty, cast bearing bronzes or higher-tin grades are usually considered.
Machinability and fabrication
Machinable, but not a free-cutting alloy – expect lower machining rates than leaded grades such as C54400. Cold forming and bending are among its strengths. Joining by soldering and brazing is practised; welding is not typical and should be reviewed for the application.
Common industrial applications
- Springs and spring-type components
- Electrical contacts and connectors (as strip/sheet)
- Fasteners, clips and washers
- Diaphragms and flexible elements
- Bushings and wear parts for light to moderate duty
- Chemical and process hardware in compatible environments
Examples only. Suitability must be confirmed for the actual operating environment.
Available product forms
- Phosphor Bronze Rod — C51000
- Phosphor Bronze Plate — C51000
- C51000 Phosphor Bronze Flanges (special-order / application-specific)
Sizes, tolerances and stock are not published and must be confirmed with the company.
Standards and specifications
- ASTM B139/B139M – phosphor bronze rod, bar and shapes
- ASTM B103/B103M – phosphor bronze plate, sheet, strip and rolled bar
- Alloy and product-form coverage to be confirmed against the current edition before specifying
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 C51000 is confirmed with the company for each order; no certificate is implied by this page.
Related grades
Frequently asked questions
Is C51000 the same as C51900?
No. Both are tin-phosphorus bronzes, but C51900 has a higher nominal tin range, which generally increases strength and wear resistance and reduces formability.
Is C51000 free-cutting?
No. It is not a leaded alloy. If high-speed machining is the priority, C54400 is the usual phosphor bronze to consider.
Can I get a material test certificate?
Documentation options depend on the order and are confirmed by the company. State your requirement (for example EN 10204 type) on the inquiry.
Need C51000 in a specific form?
Share your grade, dimensions, quantity and technical requirements with our team.