ASTM International

Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials
 N E92

Annotation

These test methods cover the determination of the Vickers hardness and Knoop hardness of metallic materials by the Vickers and Knoop indentation hardness principles. This standard provides the requirements for Vickers and Knoop hardness machines and the procedures for performing Vickers and Knoop hardness tests.

This standard includes additional requirements in annexes:

This standard includes nonmandatory information in an appendix which relates to the Vickers and Knoop hardness tests:

This test method covers Vickers hardness tests made utilizing test forces ranging from 9.807 ? 10-3 N to 1176.80 N (1 gf to 120 kgf), and Knoop hardness tests made utilizing test forces from 9.807 ? 10-3 N to 19.613 N (1 gf to 2 kgf).

Additional information on the procedures and guidance when testing in the microindentation force range (forces ? 1 kgf) may be found in Test Method E384, Test Method for Microindentation Hardness of Materials.

Units—When the Vickers and Knoop hardness tests were developed, the force levels were specified in units of grams-force (gf) and kilograms-force (kgf). This standard specifies the units of force and length in the International System of Units (SI); that is, force in Newtons (N) and length in mm or ?m. However, because of the historical precedent and continued common usage, force values in gf and kgf units are provided for information and much of the discussion in this standard as well as the method of reporting the test results refers to these units.

NOTE 1—The Vickers and Knoop hardness numbers were originally defined in terms of the test force in kilogram-force (kgf) and the surface area or projected area in millimetres squared (mm2). Today, the hardness numbers are internationally defined in terms of SI units, that is, the test force in Newtons (N). However, in practice, the most commonly used force units are kilogram-force (kgf) and gram-force (gf). When Newton units of force are used, the force must be divided by the conversion factor 9.80665 N/kgf.