A test to measure the impact properties of steel. A prepared test piece, usually notched, is broken by a swinging pendulum. The energy consumed in breaking the test piece is measured in Joules. The more brittle the steel the lower the impact strength. Izod is a similar and more widely used impact test in this country. Both are quoted in the current edition of BS 970.

A test used to determine the degree of toughness of a steel. A standard Charpy test specimen is 10mm square in cross-section, 55mm long and has a V-notch mechined in it at mid-length. The specimen is supported in a machine in which it is fractured by a swinging pendulum. The energy absorbed in fracturing the specimen in Joules (J) is read from a scale on the instrument, and is a measure of the toughness of the steel being tested. (See BS EN 10045-1: 1990). Charpy tests are usually conducted over a range of temperatures in order to determine the ductile-brittle transition temperature of a steel.

A test made to determine the notched toughness, or impact strength, of a material. The test gives the energy required to break a standard notched specimen supported at the two ends.