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Impact Tests for Tool Steel

Steel is a metal that is used extensively because of its strength, hardness, robustness, and resistance to corrosion. Tool steel, as the name suggests, refers to steel that is used to make tools. This is because tool steels are particularly hard, resistant to abrasion, and resistance to deformation at high temperatures. Tool steel has a typical carbon content by weight of 0.7% to 1.5%, with the balance being made up by iron.

Charpy Impact Test
- The Charpy impact test is designed to test the resistance of a material to fracture when it is subjected to a sudden, intense, blow. The Charpy impact test is a widely-used standardised testing method. The Charpy impact test measures the amount of kinetic energy that a sample of a material absorbs during fracture. This is a measure of how tough the material is. The test was created by a French scientist called Georges Charpy in 1905. In the Charpy test the sample is cut to specified dimensions, including a single v-shaped notch cut into one side. This notch is perpendicular to the floor. The sample is placed against a support. A pendulum with a hammer at the end is then applied to the side of the sample opposite the notch. After fracturing the sample the height to which the hammer swings is indicative of the energy absorbed by the material during fracture.
Izod Impact Test
- The Izod impact test is very similar to the Charpy impact test. The main difference lies in the dimensions of the sample and the fact that the sample is held within a clamp, rather than against a support. In the Izod impact test the hammer pendulum is applied to the face of the sample on which the notch has been cut, and the point of impact is above the notch. In the Izod test the notch is horizontal, to the floor. The Izod test was created by an English engineer called Edwin Gilbert Izod in 1903.
Rockwell Hardness Test
- The Rockwell hardness test is a test of the resistance of a material to localised plastic deformation, or the 'hardness' of a material. The Rockwell hardness test involves measuring the differences of the depths of the indentation created when a small point load is applied to a material and when a larger point load is applied to a material. The point load in the Rockwell hardness test is a cone made with a diamond.
Vickers Hardness Test
- The Vickers hardness test is very similar to the Rockwell hardness test. The main difference is that the Vickers hardness test uses a diamond indenter in the shape of a triangle-based pyramid.

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