Inside the Evolution Laboratory: How Charpy Impact Testing Works
Our latest laboratory video introduces the Charpy impact test machine and explains how it helps determine the amount of energy a material can absorb when subjected to sudden impact loading.
The machine is the latest addition to the growing range of testing equipment available at the Evolution Laboratory and Training Centre in Glasgow.
What is a Charpy impact test?
A Charpy impact test is a destructive test used to measure the energy absorbed by a notched material specimen during a sudden impact.
The result, recorded in joules, provides an indication of the material’s notched impact toughness under the specific conditions of the test.
This can help engineers understand how a material responds when subjected to a rapid load rather than the slower, gradually applied force used during a conventional tensile test.
How does the test work?
A carefully prepared specimen containing a defined notch is positioned horizontally across two supports inside the machine. The notch faces away from the pendulum so that the striker impacts the opposite face of the specimen.
The machine uses a pendulum of known mass and length. It is raised to a predetermined height, giving it a known amount of potential energy, before being released.
The pendulum then swings down under gravity and strikes the specimen. This impact places the material at the root of the notch into a tensile state, concentrating stress in that area and encouraging deformation or fracture to begin at a controlled location.
Depending on the material’s notched impact behaviour and the conditions of the test, the specimen may deform, fracture completely or remain partially connected.
After striking the specimen, the pendulum continues its swing. The energy absorbed during the impact is determined by comparing the pendulum’s potential energy before the test with its remaining potential energy after passing through the specimen.
The resulting absorbed energy is expressed in joules.
Why is Charpy impact testing useful?
Materials do not always respond in the same way under gradual and sudden loading. Factors including material composition, manufacturing process, heat treatment, specimen geometry and test temperature can all influence impact behaviour.
Charpy testing can help with:
Comparing different materials or production batches.
Assessing notched impact toughness.
Investigating brittle and ductile fracture behaviour.
Evaluating how temperature affects material performance.
Supporting product development and quality investigations.
Identifying changes resulting from material processing or heat treatment.
The result relates to the defined specimen and test conditions. It should therefore be considered alongside other relevant test data rather than treated as a direct measurement of the performance of a complete component or fastening system.
Expanding our laboratory capabilities
The Charpy impact test machine adds another valuable capability to the Evolution Laboratory and Training Centre.
It complements our existing equipment for tensile testing, torque testing, hardness measurement, material analysis and corrosion testing.
By continuing to invest in equipment, training and technical expertise, Evolution can provide customers with greater support during product development, specification and application investigations.
Our laboratory also supports UKAS-accredited testing within its approved scope, alongside broader development, comparative and investigative testing services.
Watch the test in action
Watch our latest video to see the Charpy impact test machine in operation and learn how the absorbed energy is determined.
Discover more about the Evolution Laboratory and speak to our technical team about your testing requirements.
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