The impact test is a method for evaluating the toughness and notch sensitivity of engineering materials. It is usually used to test the toughness of metals, but similar tests are used for polymers, ceramics and composites. Metal industry sectors include Aerospace, Power Generation, Automotive, and Nuclear.
The notched test specimen is broken by the impact of a heavy pendulum or hammer, falling at a pre-deterined velocity through a fixed distance. The test measures the energy absorbed by the fractured specimen.

Charpy, ASTM E23 - A test specimen is machined to a 10mm x 10mm (full size) cross-section, with either a “V” or “U” notch. Sub-size specimens are used where the material thickness is restricted. Specimens can be tested down to cryogenic temperatures.

Keyhole, ASTM E23 - The steel casting industry uses this type of specimen more frequently. The notch is machined to look like a keyhole. It is tested in the same manner as the “V” and “U” notch.

Izod, ASTM E23 - The test specimen is machined to a square or round section, with either one , two or three notches. The specimen is clamped vertically on the anvil with the notch facing the Hammer.