Izod vs Charpy Methods
The izod test involved the striker, the testing material, and the pendulum. The striker was fixed at the end of the pendulum. The test material was fastened at a vertical position at the bottom, and the notch was facing the striker. The striker swings downward, hitting the test material in the middle, at the bottom of it’s swing, and is left free at the top. The notch is placed to concentrate the stress, and provoke delicate failure. It lowers distortion and decreases the ductile fracture. The test was done easily and quickly to examine the quality of the materials, and test whether it meets the specific force of collision properties. It is also used to evaluate the materials for overall hardiness. It is not applicable to compound materials because of the influence of complicated and inconsistent failure modes.
The notch is very important because it can affect the result of the test. The making of the notch has been a problem. Initially, the radius of the notch is crucial. The radius should not change. It has an essential effect on the competence of the sample to absorb the collision. The blades in the notch can overheat the polymers, and deteriorate the materials surrounding the notch, which could lead to an inaccurate test result. The Izod method chose a short projection, supported at one end, to produce better steel tools for cutting metal.
The Charpy method includes striking an appropriate test material with a striker fastened at the end of a pendulum. The test material is secured horizontally in place at both ends, and the striker hits the center of the test material, behind a machined notch. The notch is positioned away from the striker, fastened in a pendulum. The test material usually measures 55x10x10 millimeters. The Charpy method has a machined notch across one of the larger faces. There are two types of charpy notch, a V-notch or a U-notch. The V-notch, or the AV-shaped notch, measures 2 millimeters deep, with a 45 degree angle and 0.25 millimeter radius, parallel to the base. The U-notch, or keyhole notch, is 5 millimeters deep notch, with a 1 millimeter radius at the bottom of the notch. Higher speeds and collision energy could be achieved in a vertical style fall. This method proved to be reliable, and gave qualitative collision data.
Summary:
1. In the Izod method, the test material was placed in a vertical position, while in the Charpy method, the test material was placed horizontally.
2. The notch in the izod test is facing the striker, fastened in a pendulum, while in the charpy test, the notch is positioned away from the striker.
3. In the Charpy method, there are two kinds of notches, the V-notch and the U-notch, while in the Izod method, there is only one kind of notch.