Brinell Hardness


The hardness measurement according to Brinell

With Brinell hardness measurement, a steel or carbide ball is pressed into the material to be tested. The size of the depression is a measure of the hardness of the material. The diameter of the depression is converted into a number called the “Brinell Hardness” using a formula.

The diameter of the steel ball must always be matched to the material to be measured. The underside of the material must not deform during measuring. To enable a clear reading, the depression should not be too deep. The difference in impression would become too difficult to see. A minimum compression is another requirement. The diameter of the depression should be between 0.2 and 0.7 times the diameter of the ball. Standard diameters are: 1, 2.5, 5 and 10 mm.

Calculation of hardness according to Brinell:

The Brinell hardness can be calculated using the diameter of the ball, the diameter of the depression and the load on the ball.

HB = (0.102 x load)/area of ​​indentation
HB = 0.102 x F/A

HB = the hardness according to Brinell
0,102 = a conversion factor. In the past the force was expressed in kgf, nowadays in Newton. To achieve the same Brinell hardness, a conversion factor is required.
F = the force on the ball in N
A = the area of ​​the depression in mm2
D = the diameter of the bullet
d = the diameter of the depression

Indication of hardness according to Brinell:

Indication : 300 HB

This designation is used to indicate a measurement with a ball diameter of 10 mm, a test load of 29420 N and a load time of 10-15 s. This is a commonly used measurement.

Indication : 200 HBS 10/3000/15

  • 200 hardness value
  • HBS test according to Brinell performed with a steel ball
  • 10 diameter of the bullet = 10 mm
  • 3000 load (= 3000/0,102) N = 29 410 N
  • 15 duration of the test = 15 s

Indication : 350 HBW 5/250/30

  • 350 hardness value
  • HBW test according to Brinell performed with carbide ball
  • 5 diameter of the bullet = 5 mm
  • 250 load = (250/0,102) N = 2451 N
  • 30 duration of the test = 30 s

Properties of the Brinell hardness measurement:

  • The Brinell hardness measurement is limited by the deformation of the ball. With materials harder than 500 HB, the ball will deform.
  • By using a fairly large depression (ball 10 mm), it is possible to measure the hardness of non-homogeneous materials. This is important for measurements on cast iron.
  • There is a relationship between hardness and tensile strength. For steel Rm = 10/3 HB. For aluminum Rm = 0.55 HB

More information


Became curious?

Do you have any questions about cast iron, cast steel or our machine factory? Please contact us.

Call or email us.