The material: 'UNS C51900 R350' you were looking for has been superseded by the one below.

UNS C51900 R350

Want to keep this datasheet? Save it now in your required format


CuSn6 provides an excellent combination of strength, cold formability and hardness. It is wear resistant, has good corrosion resistance and soldering properties. Due to its high strength and good spring properties combined with good machining properties it is used for all kind of springs, Bourdon tubes or flexible metal tubes.

Equivalent Materials

This material data has been provided by Matmatch.

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.

Ashby charts

See where falls on the material property chart for against in your materials selection and design process. Our Ashby charts are interactive with more technical data upon clicking. Sign up to get access to this premium feature for free.





23.0 °C

8.8 g/cm³

Show Material materials with Density of 8.8 g/cm³



Bendability 90°, bw

23.0 °C

0 [-]

Show Material materials with Bendability 90°, bw of 0 [-]

r = x t, t <0.5mm

Bendability 90°, gw

23.0 °C

0 [-]

Show Material materials with Bendability 90°, gw of 0 [-]

r = x t, t <0.5mm

Elastic modulus

23.0 °C

102 - 118 GPa

Show Material materials with Elastic modulus of 102 - 118 GPa

depending on the condition

Elongation A50

23.0 °C

45 %

Show Material materials with Elongation A50 of 45 %

Hardness, Vickers

23.0 °C

80 - 120 [-]

Show Material materials with Hardness, Vickers of 80 - 120 [-]

Tensile strength

23.0 °C

350 - 420 MPa

Show Material materials with Tensile strength of 350 - 420 MPa

Yield strength Rp0.2

23.0 °C

300 MPa

Show Material materials with Yield strength Rp0.2 of 300 MPa




Coefficient of thermal expansion

100.0 °C

1.8E-5 1/K

Show Material materials with Coefficient of thermal expansion of 1.8E-5 1/K

for 20°C to the mentioned temperature

200.0 °C

1.85E-5 1/K

Show Material materials with Coefficient of thermal expansion of 1.85E-5 1/K

for 20°C to the mentioned temperature

Specific heat capacity

23.0 °C

377 J/(kg·K)

Show Material materials with Specific heat capacity of 377 J/(kg·K)

Thermal conductivity

23.0 °C

75 W/(m·K)

Show Material materials with Thermal conductivity of 75 W/(m·K)



Electrical conductivity

23.0 °C

9.00E+6 - 1.50E+7 S/m

Show Material materials with Electrical conductivity of 9.00E+6 - 1.50E+7 S/m


Specific Electrical conductivity

15.5 % IACS

Show Material materials with Specific Electrical conductivity of 15.5 % IACS


Chemical properties





0.1 %

Show Material materials with Iron of 0.1 %



0 - 0.02 %

Show Material materials with Lead of 0 - 0.02 %


0 - 0.2 %

Show Material materials with Nickel of 0 - 0.2 %


0 - 0.2 %

Show Material materials with Other of 0 - 0.2 %


0.01 - 0.4 %

Show Material materials with Phosphorus of 0.01 - 0.4 %


5.5 - 7 %

Show Material materials with Tin of 5.5 - 7 %


0 - 0.2 %

Show Material materials with Zinc of 0 - 0.2 %

Technological properties

Application areas

Electrical: Miniaturized Connectors, Contact Springs, Relais Springs, Electrical Flexing Contact Blades, Terminals, Switch Parts, Fuse Clips, Electronic Connectors, Resistance Wire, Electromechanical Spring Components, Electrical Flexing Contact Blades, Wire Brushes, Switch Parts, Electronic and Precision Instrument Parts. Fasteners: Lock Washers, Cotter Pins, Fasteners. Industrial: Bourdon Tube, Bellows, Textile Machinery, Perforated Sheets, Springs, Sleeve Bushing, Clutch Disks, Beater Bar, Chemical Hardware. General: Stamped parts, Connectors, Contact springs, Spring elements, Ultra high strength spring elements, Membranes, Switch elements, Fixed contacts.



Cold Forming

Max. 70 % between annealings, excellent

Corrosion properties

CuSn6 has a good resistance to seawater, different agents and industrial atmosphere and has a good resistance to tarnishing. It is in a large extend resistant to pitting corrosion. Even in seawater the laminar attack is higher than localized corrosion.

Heat Treatment

Temper: R350

Hot forming

at 750-850°C, limited


Rating 20, less suitable


This alloy is in accordance with RoHS 2002/96/CE for electric & electronic equipments and 2002/53/CE for automotive industry.


Electroplating is excellent


Gas Shielded Arc Welding: Good, Laser Welding: Good