Different aspects of Impact Testing Procedure

Impact evaluation

The impact value might fluctuate in a positive association with temperature. As a result, the impact energy of the material is typically smaller the lower the temperature. The material’s impact energy increases with increasing temperature.

The Izod Impact Tester’s results are significantly impacted by size. The element makes it possible for the material to develop a number of flaws. They may operate as stressors, reducing the effect of energy.

The capacity of a substance to absorb energy during deformation is measured by its toughness. Low-toughness materials frequently have a limited tolerance for plastic deformation.

Different Tests

The impact value of materials is evaluated using a variety of tests. IZOD and Charpy impact testers are frequently used in impact testing.

Impact Test IZOD

The impact resistance of specimens is tested using various standard test setups using the Izod Impact Tester, also known as the Pendulum Impact Tester. The test comprises a swinging hammer or pendulum, a support frame, and a measurement instrument that measures absorbed energy at a 90-degree angle.

The test’s notch impact determines the material specimen’s behaviour at faster deformation rates. To calculate the impact energy that the material specimen absorbed before breaking, the height of the pendulum’s rise after impact is measured.

The specimen will be supported during testing as a cantilever beam. The latching position is set to 90 degrees, and the striker must fit snugly in the hammer.

The pointer will indicate the amount of energy spent by the metal specimen based on its rupture after the metal specimen is positioned on the support with its notch facing the direction of the striker and the hammer is released.

To assess the impact value of certain specimens, this testing method uses a high strain-rate test. These impact specimens are available in industrial standards including ASTM E23, ASTM A370, EN 10045 Series, and ISO 148 and have standard dimensions.

Impact Test Charpy

The Charpy Impact Tester is used for equipment that can measure loads between one and three hundred foot-pounds at temperatures between -320°F and over 2000°F. A notched specimen is struck by a controlled weight pendulum swung from a predetermined height in this high-strain rate test.

This test, which is regarded as a good metal impact tester, gauges how much impact energy the specimen absorbs as it is struck by the pendulum. It reveals if a specimen, particularly ferritic steels, can be categorized as ductile or brittle.

The metal specimen will be supported on all sides during the metal impact test, and the appropriate striker must fit in the hammer. For the Charpy test, the latching angle is 140 degrees.

The pointer will display the frictional losses or the amount of energy used by the metal specimen after the metal specimen is set on the support block and the hammer is let go.

The specimen is struck by a pendulum-mounted “tup,” which causes the metal sample, also known as the V-notch Impact, to break at its notched cross-section. The toughness of the material is shown by measurements in Joules. According to the findings, fragile metals take in a little quantity of energy. A strong ductile metal, on the other hand, can hold a lot of energy.

In addition to the impact energy taken in, the metal specimen’s fracture can also reveal how tough it is. A ductile fracture appears dull and fibrous, while a brittle fracture is brilliant and crystalline. The degree of crystalline or brittle fracture on the surface of the broken metal specimen determines the percentage of crystallinity.

The Charpy test and the Izod test have some key distinctions. They consist of the notch, the specimen position, and the hammer type.

In the Izod technique, the specimen is always in a vertical position. In contrast, because it is supported on all sides when using the Charpy approach, the specimen is always horizontal.

The Charpy technique uses the V-notch and the U-notch among its notches. Only one kind of notch, facing the striker and secured in a pendulum, is used by the Izod.

The Izod technique employs an agricultural hammer as the striker. A ball pin hammer is the one used in the Charpy procedure.

The metals may now go through broaching or notching after being tested, whether by Izod or Charpy Impact Testing. Using a toothed tool to remove the material or make a cut is known as broaching. Contrarily, notching is a metal-cutting technique applied to thin or sheet metal using a shearing or punching procedure.

For handling thicker types of metal, a broaching machine is utilized, whereas a notching machine is used for slender or thin metals. Moreover, the two machines can be combined into one to generate two items at once.

Video 01: Charpy Impact Test