When quoting a Brinell hardness number (BHN or more commonly HB), the conditions of the test used to obtain the number must be specified. (HB is not related to the "HB" degree of pencil hardness.) The standard format for specifying tests can be seen in the example "HBW 10/3000". "HBW" means that a tungsten carbide (from the chemical symbol for tungsten or from the Swedish/German name for tungsten, "Wolfram") ball indenter was used, as opposed to "HBS", which means a hardened steel ball. The "10" is the ball diameter in millimeters. The "3000" is the force in kilograms force.
The hardness may also be shown as XXX HB YYD2. The XXX is the force to apply (in kgf) on a material of type YY (5 for aluminum alloys, 10 for copper alloys, 30 for steels). Thus a typical steel hardness could be written: 250 HB 30D2. It could be a maximum or a minimum.
Correspondent relations among scale, indenter and test force:
|Hardness symbol||Diameter of Indenter|