A Guide To Rebound Hardness And Scleroscope Test
Introduction
Explore, as you will, the relationship between rebound hardness and Scleroscope, you shall be introduced to a rather unique hardness measure test – the Rebound Hardness Test or the Dynamic Hardness Test. The Rebound Hardness Test measures hardness of materials in terms of the ‘height of rebound of the indenter’ dropped on the materials surface with the help of a special device known as the ‘Scleroscope’. Put in other words, the Scleroscope measures hardness in terms of the elasticity of the material, where the hardness number is dependent on the height to which the hammer rebounds. The harder the material, the higher is the rebound.
The Scleroscope test to determine rebound hardness involves dropping a diamond tipped hammer (falling under the force of its own weight from a fixed height) on the sample material. The height of the rebound travel of the hammer is measured on a graduated scale, depending on the model being used. The C Scleroscope testers make use of a glass tube graduated from 0 to 140 to measure the height of rebound and the D model had a 0 to 120 dial-gauge to determine the rebound height.
Application and Advantages of Scleroscope Test
Being portable, the Scleroscopes are used for measuring the rebound hardness of a wide variety of metallic parts, only that the size of the sample material should be large enough to cause maximum possible bounce. Well-finished, smooth metal rolls give the best rebound hardness measures as part of the Scleroscope test.
The Scleroscope test is a non-marking test and since it does not leave any indent on the sample material, it can be used immediately after the test without any refinishing.
Updates On The Scleroscope
The Scleroscope test has been used to the greatest advantage in the development of electronic instruments for measuring rebound hardness of materials. These electronic devices make use of a spring to get a spherical, tungsten carbide tipped object moving towards the sample material surface.
The other difference is that unlike Scleroscopes, these instruments measure the loss of energy of the impact body. Thus, they measure the two velocities – the velocity of the body before and after the impact. The difference between the two velocities (or the loss of speed) gives the hardness number of the material and it can be arrived at by using any of the common hardness scales like the Brinell or Rockwell scales.
About the Author
Allen is a successful writer and publisher of Hardness Tester related issues, for more informative articles go to www.hardnesstesters.info
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