Physical Properties of Beryllium Copper

BeCu wrench
•••

 Guy Immega/Wikimedia Commons

Beryllium copper alloys are vital to a number of industries due to their unique combination of strength, hardness, conductivity, and resistance to corrosion.

Standard beryllium copper alloys contain close to 2 percent beryllium, while the beryllium content in proprietary alloys can range from 1.5 to 2.7 percent.

The standards in the chart below should be for reference only, as alloys can be subject to considerable variation depending upon conditions of heat treatment.

For example, thermal and electrical conductivity can increase with precipitation hardening. Also of note, is that the precipitation heat treatment that creates maximum hardness does not correspond with that which provides maximum conductivity.

Physical Properties of Beryllium Copper

Properties

Measurement

Density

8.25g/c3
0.298lb/in3

Coefficient of Thermal Expansion

17 x 10-6 per C
9.5 x 10-6 per F

Electrical Conductivity

Solution heat-treated
Heat-treated to maximum hardness
Heat-treated to maximum conductivity


16 to 18 percent (IACS)
20 to 25 percent (IACS)
32 to 38 percent (IACS)

Electrical Resistivity at 20°C

Solution heat-treated
Heat-treated to maximum hardness
Heat-treated to maximum conductivity

9.5 to 10.8 microhm cm
6.9 to 8.6 microhm cm
4.6 to 5.4 microhm cm

Temperature Coefficient of Electrical
Resistance, from 0°C to 100°C

Heat-treated to maximum conductivity



0.0013 per °C

Thermal Conductivity

Solution heat-treated
Precipitation hardened

0.20 cal./cm2/cm./sec./°C
0.25 cal./cm3/cm./sec./°C

Specific Heat

0.1

Modulus of Elasticity

Tension (Young's modulus)
Torsion (Bulk or shear modulus)


18 to 19 x 106lb./sq. inch
6.5 to 7 x 106lb./sq. inch

Temperature coefficient of elastic modulus

Tension, from -50°C to 50°C
Torsion, from -50°C to 50°C


-0.00035 per °C
-0.00033 per °C

Source: Copper Development Association. Pub 54. Beryllium Copper (1962).

Uses of Beryllium Copper Alloys

Beryllium Copper is commonly used in electronic connectors, telecommunications products, computer components, and small springs. Tools like wrenches, screwdrivers, and hammers used on oil rigs and coal mines have the letters BeCu on them, indicating there are made of Beryllium Copper and safe to use in those environments because they won't cause potentially deadly sparks.