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C510
Phosphor Bronze Round Bar
C51000
Overview
C51000 (Phosphor Bronze A) is the most widely used wrought phosphor bronze alloy. The addition of phosphorus (up to 0.35%) as a deoxidizer produces a tough, strong alloy with excellent fatigue resistance and spring properties. C510 is the standard material for springs, electrical contacts, switch parts, and fasteners. It offers a good balance of strength, formability, and corrosion resistance, making it versatile for both electrical and mechanical applications.
Chemical Composition
| Element | Min | Max |
|---|---|---|
| Copper (Cu) | Balance (~94.8%) | — |
| Tin (Sn) | 4.20% | 5.80% |
| Phosphorus (P) | 0.03% | 0.35% |
| Iron (Fe) | — | 0.10% |
| Lead (Pb) | — | 0.05% |
| Zinc (Zn) | — | 0.30% |
Alloy Designations
UNSC51000
ASTMB103, B139
Common NamePhosphor Bronze A / Spring Bronze
Mechanical Properties
Tensile Strength (H04 Hard)66 ksi (455 MPa)
Yield Strength (H04 Hard)58 ksi (400 MPa)
Elongation (H04)10%
Hardness (H04)82 HRB
Fatigue Strength28 ksi (193 MPa)
Machinability20
Physical Properties
Density8.86 g/cm³ (0.320 lb/in³)
Melting Point999–1,060°C (1,830–1,940°F)
Electrical Conductivity15% IACS
Thermal Conductivity69.0 W/m·K
Modulus of Elasticity110 GPa (16,000 ksi)
Typical Applications
- Springs and spring contacts
- Electrical connectors and switch parts
- Bellows and Bourdon tubes
- Fasteners, bolts, and washers
- Chemical hardware
- Perforated sheets and woven wire
Fabrication & Joining
- Excellent cold working and spring properties
- Good hot formability
- Soldering: Excellent
- Brazing: Good
- Welding: Fair (resistance welding preferred)
- Low machinability — use sharp tools