Charpy impact testing measures the toughness of a material at a given temperature. During the application of a single impact load (high strain rate), the energy absorbed by the test specimen is measured.

This test it typically performed at temperatures that can range from near ambient, to as cold as liquid nitrogen. By testing multiple specimens over a range of temperatures the ductile to brittle transition temperature of a metal can be established.

A frequent application of Charpy impact testing is to verify the toughness of a material to acceptance criteria at a fixed temperature. 

Charpy Impact Testing is done according to ASTM E23 Notched Bar Impact Testing of Metallic Materials.