Types of Indentation Tests

Thursday, June 11, 2015

Brinell: Formulated in the 1900's the Brinell hardness test was the first standardized indentation-hardness test. The Brinell test consists of indenting the metal surface with a 10 milimeter diameter steel ball at a specified load range. The Brinell hardness test is typically used on small specimens and is less influenced by surface scratches and roughness compared to other harness tests.

Meyer: The Meyer hardness is a more fundamental measure of indentation hardness, but is rarely used for practical measurement. The Meyer hardness test measures the mean pressure between the surface of the indenter and the indentation.

Vickers: The Vickers harness test is a much slower process, which requires careful surface preparation. The Vickers hardness test uses a square-base diamond pyramid as the indenter with an included angle of 136 degrees with loads ranging from 1-120kgf applied for 10 to 15 seconds at a time, leaving one of three types of indentations: square, pincushion and barrel-shaped. Vickers hardness tests are widely accepted for research purposes because it provides a continuous scale of hardness for a given load. Vickers hardness can also be measured on a micro scale using the same fundamental methods.

Rockwell: The Rockwell hardness test is the most widely used hardness test in the US and is generally accepted due to speed, lack of personal error and the ability to distinguish small hardness differences. With Rockwell hardness testing the hardness is measured according to the depth of indentation under a constant load. Rockwell also has its own hardness scale represented by A, B, C…depending on the types of indenters and loads used.

Knoop: The Knoop hardness test is used for measuring the hardness of very small areas, otherwise known as microhardness.  The diamond shaped indenter is used to measure the small area, such as a cross section of a heat-treated metal surface.

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