Hardness Testing

Hardness Testing is a measurement technique.  It is performed to determine a material’s resistance to plastic (permanent) deformation, and is useful in realizing a material’s response to a heat treatment process.  Hardness testing results may be used to approximate mechanical properties of parts without destroying them.  A hardness test does, however, leave a permanent mark on the test sample; this classifies the method as a destructive test. The affected area, however, is usually small enough to be of no concern. There are a number of different hardness testing methods, the most popular and useful method is the Rockwell Hardness Test.  Others include Brinell, the largest and heaviest hardness testing process, and Vickers and Knoop micro-hardness tests which leave a mark so small as to be mostly indiscernible to the human eye.

To perform hardness testing, one uses a test machine to make an impression in a test sample using a known weight and penetrator dimension. In the case of the Rockwell test, the depth of the penetration is measured by the machine.  For Brinell and micro-hardness testing, the size of the mark is measured under a scope with graduations. To determine a hardness testing machine is working properly, hardness test blocks are used by the inspector. The blocks have been calibrated against hardness standards and certified to a tolerance.

Solar Atmospheres performs all methods of hardness testing, with Nadcap accreditation for the Rockwell method. If you have any questions how hardness testing can add value to your process, please contact a Solar Atmospheres Sales representative.