Hardness Testing

Conventional hardness testers, like Rockwell, Brinell or Vickers machines, require the test piece be brought to the testing device; but this is not always possible. Portable testing devices have been developed that permit in-situ hardness measurements thus offering quick and economical supplements to conventional, stationary testing machines.

This paper explains the basic principles of both test methods and compares, using examples from the practical field, the application possibilities of both methods. The subjects critically discussed are the factors of influence on hardness testing, such as surface preparation or the wall thickness of parts to be tested.

The Through Diamond Technique. This optical mobile hardness tester measures, for the first time, real Vickers hardness under load. One popular device measures the frequency shift of a resonating rod with a Vickers- diamond tip, which occurs when the diamond penetrates into the test material by applying a specific test load. The frequency shift is evaluated and electronically converted to a hardness value displayed on the LCD

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