What Does Charpy Impact Test Mean?
A Charpy impact test is a test method that is used to determine the toughness of a material. Once machined, a specimen of the material being tested is loaded into a Charpy impact test machine. The amount of force required to fracture the material with a swinging pendulum is used to calculate the toughness.
Corrosionpedia Explains Charpy Impact Test
Charpy impact testing is one of the most popular methods used to evaluate the toughness of a material, which is typically measured in ft-lbs.
To perform a Charpy impact test, the material to be tested must first be machined to a specific set of dimensions as determined by one of the national or international testing standards. The machined material is then fixtured into place. A pendulum that is part of the Charpy impact test machine is released from a horizontal position, and gravity forces the pendulum downwards towards the specimen. The pendulum impacts the specimen and continues moving past it. All of the energy during this event is measured. The forces that occurred during the test and the specimen's dimensions are used to calculate the toughness of the material.
One key characteristic of the Charpy impact test is found on the material specimen. During the machining process, a groove is machined on the backside of the specimen. This notch is machined to act as a stress concentrator, which causes the specimen to fracture more easily and in a designated location. The dimensions of this notch are critical because they are used to calculate the material's toughness.