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The typical test uses a 10 mm (0.39 in) diameter steel ball as an indenter with a 3,000 kgf (29.42 kN; 6,614 lbf) force. For softer materials, a smaller force is used; for harder materials, a tungsten carbide ball is substituted for the steel ball. The indentation is measured and hardness calculated as:
Indentation hardness tests compose the majority of processes used to determine material hardness, and can be divided into three classes: macro, micro and nanoindentation tests. [2] [3] Microindentation tests typically have forces less than 2 N (0.45 lb f). Hardness, however, cannot be considered to be a fundamental material property.
A Rockwell hardness tester. The Rockwell hardness test is a hardness test based on indentation hardness of a material. The Rockwell test measures the depth of penetration of an indenter under a large load (major load) compared to the penetration made by a preload (minor load). [1]
Meyer's law is an empirical relation between the size of a hardness test indentation and the load required to leave the indentation. [1] The formula was devised by Eugene Meyer of the Materials Testing Laboratory at the Imperial School of Technology, Charlottenburg, Germany, circa 1908.
Indentation hardness measures the resistance of a sample to material deformation due to a constant compression load from a sharp object. Tests for indentation hardness are primarily used in engineering and metallurgy. The tests work on the basic premise of measuring the critical dimensions of an indentation left by a specifically dimensioned ...
The composite hardness is known to vary depending on the applied load and or indentation depth. In the Korsunsky work-of-indentation approach, the composite hardness is given by a simple expression (the “knee function”) of the relative indentation depth (the indentation depth normalized with respect to the coating thickness), and the ...
Durometer, like many other hardness tests, measures the depth of an indentation in the material created by a given force on a standardized presser foot. This depth is dependent on the hardness of the material, its viscoelastic properties, the shape of the presser foot, and the duration of the test. ASTM D2240 durometers allow for a measurement ...
A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific comparison table for steels .