Constantan Physical Properties

Copper nickel alloy constantan wire, which has low electric resisitance, good heat-resistant and corrosion-resistant, easy to be processed and lead welded. It is used to make the key components in the thermal overload relay, low resistance thermal circuit breaker, and the electrical appliances. It is also an important material for electrical heating cable. It’s similar as ‘s type cupronickel.

The physical properties of constantan are:

Melting point – 1225 to 1300 oC

Specific Gravity – 8.9 g/cc

Solubility in Water – Insoluble

Appearance – A silver-white malleable alloy

Electrical resistivity at room temperature: 0.49 µΩ/m

At 20°c – 490 µΩ/cm

Density –  8.89 g/cm3

Temperature Coefficient ±40 ppm/K-1

Specific heat capacity 0.39 J/(g·K)

Thermal Conductivity 19.5 W/(m.K)

Elastic Modulus 162 GPa

Elongation at fracture  – <45%

Tensile strength – 455 to 860 MPa

Linear Coefficient of Thermal Expansion     14.9 × 10-6 K-1