Phosphor Bronze

C51000 Bronze

Specs: ASTM-B-139, AMS 4625, QQ-B-750
UNS# C51000

The term “bronze” broadly refers to Copper alloys in which the major alloying element is neither Zinc (which forms brass) nor Nickel (which forms Copper- Nickel).


C51000 Bronze (CuSn5) is a Tin Bronze that contains Copper, Tin, and Phosphorous. The Tin increases corrosion resistance and strength, while the Phosphorous increases wear resistance and stiffness.


Phosphor Bronze alloys are best known for their elastic properties and are often used for spring-loaded electrical contacts, various electrical connectors, sleeve bushings, clutch discs, and fasteners. C51000 Bronze brazes and solders extremely well and has excellent cold working capacity.


Phosphor Bronze C51000 (CuSn5) is a tin bronze with the addition of 5% tin and 0.2% phosphorus for deoxidation. The tin increases the strength of the alloy and gives good corrosion resistance in marine environments.


C51000 is one of the most widely used phosphor bronzes, owing to its unique combination of properties.


The alloy offers an optimized combination of engineering properties, such as high strength and ductility, excellent fatigue and spring characteristics coupled with good corrosion resistance. It has excellent bearing properties with a low coefficient of friction and high wear resistance.


In addition, it has good cold-forming properties and spring properties with excellent resistance to stress relaxation.


The alloy has an adequate electrical and thermal property, which helps it find applications in current-carrying and heat transfer applications.


C51000 has superb cold working characteristics, which enables the alloy to be supplied in the half-hard, fully hard, spring, and extra spring conditions.


It can be joined by soldering, brazing, and considered good to be joined by carbon arc welding or gas shielded arc welding; it has a machinability rating of 20% compared with free machining brass at 100%.

Available shapes – round 


Related Products



  • Bridge Bearing Plates


  • Terminals
  • Contacts
  • Switch Parts
  • Electromechanical Spring Components
  • Resistance Wire
  • Electrical Flexing Contact Blades
  • Electrical Connectors
  • Electronic Connectors
  • Wire Brushes
  • Electronic and Precision Instrument Parts
  • Fuse Clips
  • Terminal Brackets


  • Lock Washers
  • Fasteners
  • Cotter Pins


  • Bellows
  • Textile Machinery
  • Perforated Sheets
  • Chemical Hardware
  • Truss Wire
  • Mechanical Springs
  • Sleeve Bushings
  • Diaphragms
  • Clutch Disks
  • Bourdon Tubes
  • Beater Bar
  • Welding Rods
  • Pressure Responsive Elements
  • Sprinkler Parts
  • Textile Machinery Parts

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Specifications of Phosphor Bronze 51000

Tube & Pipe
Welded & Seamless
Sheet & Plate Strip Rod, Bar
& Profile
  ASTM B 100
ASTM B 103
ASTM B 103 ASTM B 139 ASTM B 159
AMS   AMS 4625 AMS 4510   AMS4625  
SAE CA510       SAE J461
SAE J463
Federal   MIL T 3595       MIL W 6712
CW 451K   EN 1652 EN 1652
EN 1654
EN 13145
EN 14436
EN 12163 EN 12166
British Standard
PB 102   BS 2870
BS 2875
BS 2870 BS 2874
Def Stan 02 838
BS 2873
CuSn4P   NF A 51-108      
C2105   JIS H 3110 JIS H 3110 JIS 3270 JIS 3270
518   AS 1566 AS 1566 AS/NZS 1567 AS/NZS 1573
Czech Republic
      CSN ISO 1634-1
CSN ISO 1634-3
CSN ISO 1637 CSN ISO 1638
CuSn5     ISO 1634-1
ISO 1634-3
ISO 1637 ISO 1638
Mechanical Properties

Mechanical Properties of Phosphor Bronze 51000

Product Form Condition Size
Imperial metric
Ksi    N/mm²
0.5% Yield
Ksi    N/mm²
Rod & Bar H04 Hard <=0.25” (<=6mm) 80-128   550-880 NA    NA NA
    0.25-0.5” (6-12mm) 70-80   485-550   13-20
    >0.5-1.0” (>12-25mm) 60-70   415-485   15-22
    >1” (>25mm) 55-65   380-448   18-25
Physical Properties

Physical Properties of Phosphor Bronze 51000

Physical Properties Imperial Units Physical Metric Units
Density 0.320 lb/in³ 8.86g/cm³
Melting Range 1750-1920ºF 950- 1050ºc
Mean Liner Expansion
  0.0178 ºc x10-³
Mean Liner Expansion
68-572 ºF
0.00099 ºF x10-³  
Specific Heat 0.0908Btu/lb/ ºF @68ºF 377J/kg ºK @20 ºc
Thermal Conductivity 40Btuft² /hr-ft ºF @68ºF 69W/m. ºK
Electrical Conductivity 20% IACS @68ºF 0.088MS/cm@20 ºc
Magnetic Permeability <1.01  
Electrical Resistivity 4.53µ_in 11.5 μΩcm
Modulus of Elasticity 10³    
Tension 16ksi 110N/mm²
Rigidity 6ksi 41.370 N/mm²

While the data is believed to be accurate, Wieland Diversified makes no representation or warranty of any kind (expressed or implied) and assumes no responsibility with respect to the accuracy and values shown above; this information should only be used as a guide.

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