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C51900 Phosphor Bronze


CuSn6 - UNS.C51900 Phosphor Bronze Alloys, which is a 6% tin bronze distinguished by a very good combination of strength and electrical conductivity. It is used for connector and current-carrying springs in contacts. Among the 4-8% tin bronze C51900 exhibits a high electrical conductivity, the highest reachable strength is significantly higher than C51100 and C51000. By means of an additional further tempering after the cold forming process the bendability can be further improved.
Its adequate conductivity makes it particularly interesting for springy conductive components. It is wear-resistant, has very good corrosion resistance and can be readily soldered. Due to the higher strength and springiness and good workability, C51900 is used for all types of springs as well as for flexible metal hoses. In addition, it is applied in the paper, pulp, textile and chemical industries, as well as in shipbuilding, mechanical engineering and process equipment manufacture.


Available Products (forms):
Round bars, Flat bars, Square bars, Round Wires, Round Strips
Custom shapes are available upon request.


Chemical Composition:

Sn: 5.50-7.00%
P:  0.03-0.35%
Zn: 0.30% Max.
Fe: 0.10% Max.
Pb: 0.05% Max.
Zn: Balance

Note: Copper plus additions equal 99.50% minimum.


Typical Physical Properties:

Specific Gravity: 8.80 g/cm3
Coefficient of Thermal Expansion per °C: 18.50 x 10-6 (20-300°C)
Electrical Conductivity (% IACS): 15.50 % @ 68 F
Thermal Conductivity: 38.00 Btu · ft/(hr · ft2·oF)at 68F
Modulus of Elasticity in tension: 16000 ksi

1). the units are based upon US Customary.
2). the typical physical properties apply to age hardened products.

International Specification:

Rods/Bars/Strips: UNS.C51900, CDA519, ASTM B139, B103, B888, B159
European Standards: CuSn6, JIS C5191, CW 452 K, PB 103