Question: What is charpy impact testing?
Answer: The Charpy impact test, also known as the Charpy V-notch test, is a standardized test which determines the amount of energy absorbed by a material during fracture. It is specified for some barrier pins to ensure the material is strong enough to prevent the barriers from moving on impact.
A v-shaped notch is cut into a rectangular sample of the steel, then the sample is cooled to a specified temperature (-20°F in the case of F1554 Grade 105). A specialized pendulum is then swung at the notch in the sample. The pendulum will cleave through the steel and the results of the test are determined based on:
- The distance the pendulum travels past the steel test piece, and
- The way the material fractures
Typically, the only barrier pins that will be subject to a Charpy impact test are parts made to ASTM F1554 Grade 105. For this test, 3 sample pieces are cooled to -20°F and the amount of energy absorbed by each piece is measured. The three samples must show an average absorbed energy of 15 ft-lbs. Additionally, at least one of the sample pieces must show a minimum absorbed energy of 12 ft-lbs. Watch a Charpy impact test here.