Difference Between IZOD and Charpy Impact Test

The name IZOD impact test was introduced by the famous English Engineer - Edward Gilbert Izod, therefore, named as IZOD Impact Test. The test is designed to test the impact resistance strength of plastics and other related raw materials. The test procedure works on the international test standard method ASTM D256. The standard defines the resistance strength of plastics when they are impacted by a pendulum shaped hammer with certain force and specified angle.

How is the Izod Impact Test performed?

Izod impact testing is done by placing the sample on the Impact tester. The major requirement of the test is to prepare the test sample by making a V-shaped notch/cut on the sample. These notches are created to make a stress bearing zone for the sample. The pendulum is first raised at a predefined height to apply a required amount of energy. Then the pendulum is released which hits the material that is placed on the machine.

The amount of energy that the sample has absorbed is calculated by the height of the arm which helps to examine the sturdiness of the sample. The energy calculated from the same is measured by Kj/m2.

Let’s discuss a few factors that can affect the test results performed using IZOD Impact tester.

Firstly, the notches. The radius, depth of the notch and the tip are the most important things to consider while performing the IZOD test. This is because some materials are more sensitive than the others.

To create a perfect notch, always make use of a notching machine. The machine utilizes a proper cutting and punching princess on the sample. In some

Secondly, the fracture mechanism.

Fracture mechanism is the ability of the test material to handle fracture or damage. Always check that while making a notch in the sample, it will not get fractured. If the sample will get damaged, you won’t be able to get the required test results.

Next is the Temperature Resistance Strength.

Lower temperature reduces the malleability of the material. If the yield strength of the material is high, it can reduce the impact energy of the material.

How is the IZOD test different from the Charpy Impact Test?

The Charpy test was introduced by Georges Charpy in the year 1900. It is also very famous for the Charpy V-Notch Impact Test.

To perform the charpy test, you need to prepare the standard sample of size 55 x 10 x 10 mm. The best part, to prepare the sample, you can either make U-notch/ a keyhole notch or a V-notch in the sample. The V-notch should be 2mm deep, with a 45 degree angle.

If you want to make a U-notch / keyhole notch then it should be 5 mm deep in size.

Charpy impact test is performed on metals and other related raw materials. After preparing the sample, a pendulum is dropped on the sample from a certain height and the test is concluded. This result is concluded by comparing the difference between the height of the hammer before and after the damage in the sample. The energy is measured by (j/m) joules per meter.

For more information on IZOD/Charpy Impact tester, consult our experts at Pacorr Testing Instruments.