brinnel hardness testing methods

	Brinell Test Method All Brinell tests use a carbide ball indenter. The test procedure is as follows: The indenter is pressed into the sample by an accurately controlled test force. The force is maintained for a specific dwell time, normally 10 - 15 seconds. After the dwell time is complete, the indenter is removed leaving a round indent in the sample.  The size of the indent is determined optically by measuring two diagonals of the round indent using either a portable microscope or one that is integrated with the load application device. The Brinell hardness number is a function of the test force divided by the curved surface area of the indent. The indentation is considered to be spherical with a radius equal to half the diameter of the ball. The average of the two diagonals is used in the following formula to calculate the Brinell hardness. The Brinell number, which normally ranges from HB 50 to HB 750 for metals, will increase as the sample gets harder. Tables are available to make the calculation simple. A typical Brinell hardness is specified as follows: