Knoop Hardness Testing

Knoop Hardness

Knoop hardness is the test force F divided by the projected area A (mm2) of the impression calculated based on the longer diagonal length d (mm) of indentation made when the pyramid shaped diamond indenter with apical angles of  130o and 172030 rhomboid cross section is pressed against the specimen by the test force F and then removed.  Knoop hardness can be replaced by replacing the indenter on micro hardness testing machines.