- Charpy impact testing is a destructive test, in which a specimen is struck with a pendulum to fracture it, and determine the amount of energy the material has absorbed.
- This energy is a measure of the material's notch toughness, which can be used to study the temperature transition between brittle and ductile specimens.
- Lateral expansion and percentage shear can also be carried out in correspondence with a charpy impact test.
- Lateral expansion is a measure of the ductility of the impact specimen.
- When a ductile material is impact tested, it will deform before breaking to create shear lips.
- The amount that the specimen deforms normally to the fracture face is measured in millimetres with a digital test indicator.
- Percentage shear measures the amount of ductile and brittle fracture on the fracture face of the broken specimen.
- The fracture surface is indicative of the type of fracture that has occurred.
- A brittle fracture looks bright and crystalline; whereas, ductile fractures have a dark and fibrous surface.
ASAMS is accredited to ISO 148 and ASTM E23 impact testing. Our charpy impact machines have a 450J capacity. A charpy cool bath is used to allow testing at temperatures between ambient and -80°C, the bath continually agitates the solution and keeps the temperature within ±1°C. ASAMS is also able to test down to -196°C using liquid nitrogen, allowing coverage of a range of needs for clients.
A charpy impact test being carried out in accordance with ISO 148.