CuSn5 - UNS.C51000 Phosphor Bronze Alloys, with a nominal composition of 94.80% copper and 5.0% tin, deoxidized with 0.2% phosphorus is the most widely used of the phosphor bronzes, which offering an optimum combinations of such engineering properties as high strength and ductility, superior fatigue and spring characteristics, excellent corrosion resistance, durability for severe service, good bearing qualities with low friction and higher wear resistance, superior forming and spinning, resistance to stress relaxation and good joining properties. In most cases, C51000 alloy has adequate electrical and thermal properties for many current-carrying and heat transfer requirements.

Flat Springs made of C51000 alloy have the following important advantages over steel springs. 

(1). Being Non-Magnetic (2). Having higher electrical and thermal conductivity (3). Greater resistance to corrosion (4). Less susceptible to combined corrosion and fatigue (5). Higher ratio of safe stress to modules allowing larger deflections with lower bending stresses (6). More easily fabricated or formed.

C51000 Alloy typical applications for phosphor bronze include bearings, bushings, gears, pinions, shafts, thrust washers and valve parts.

Typical Application for C51000 Phosphor Bronze Alloys
Architecture: Bridge Bearing Plates
Electrical: 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, Kettles, Pots, Perforated sheets, Textile Machinery parts
Fasteners: Lock Washers, Fasteners, Cotter Pins
Industrial: 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
Available Sizes:
Custom Diameter & Sizes, Random Mill lengths

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

Chemical Composition:

Sn: 4.50-5.50%
P:  0.03-0.35%
Zn: 0.30% Max.
Fe: 0.10% Max.
Pb: 0.05% Max.
Cu: Balance

Note: Copper plus additions equal 99.50% minimum.

Typical Physical Properties:

Specific Gravity: 8.86 g/cm3
Coefficient of Thermal Expansion per °C: 17.80 x 10-6 (20-300°C)
Electrical Conductivity (% IACS): 15% @ 68 F
Thermal Conductivity: 40.00 Btu · ft/(hr · ft2·oF)at 68F
Modulus of Elasticity in tension: 16000 ksi

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

International Specification:

Rods/Bars/Strips: UNS.C51000, CDA510, ASTM B139, B103, B888
European Standards: CuSn5, JIS C5102, CW 451 K, PB 102