A scleroscope is a materials testing device available for use in hardness testing of metals with carbon and graphite components, like steel. There are a number of options for hardness testing in the evaluation of materials, and this may be chosen if testers feel it is the most appropriate or if a test specifically calls for a scleroscope. Special training is required to operate the device accurately and effectively. It is important for materials testing to take place in a controlled environment to yield reliable and repeatable results.
The scleroscope consists of a glass tube with graduated markings. The operator drops a weighted hammer through the tube and onto the material of interest. As the hammer rebounds, the operator can take note of the rebound height and use this to calculate the hardness of the material. The more elastic the material, the higher the rebound, and the lower the hardness. The scleroscope may come with a chart to convert readings for ease of use.
This device was developed in the early 20th century to meet materials testing needs in industrial environments. Steel and other metals need to be reliable and consistent for best results in mass production. Companies can use a scleroscope in research and development to determine the hardness of experimental metals. The device can also be used in quality control to confirm that batches of material are consistent and meet the standards for their intended uses.
In a materials testing setting, the tester may repeat the test to confirm the accuracy of the results, and also follows a set protocol with each test. The protocol is designed to make the test repeatable, with results that can be reproduced by anyone who understands how to operate the equipment. It is also possible to combine other hardness tests for multiple readings and a broad spectrum of information about the hardness of the material.
Use of a scleroscope is an example of nondestructive testing. The tester can evaluate the properties of the material without destroying it in the process, although some metals may dent or fracture during testing. If a metal is known to be particularly soft or brittle, the technician may select a different hammer with a lighter, broader head to reduce the risk of damaging the metal. The results will need to be weighted to reflect the nonstandard hammer design, using a different hardness chart to convert the rebound information to a measure of hardness.