Brinell Hardness Testing: How To Calculate - Industrial Physics Brinell Hardness Testing: How To Calculate - Industrial Physics

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Brinell Hardness Testing: How To Calculate

Brinell Hardness Testing: how to calculate

Working out the best and most suitable hardness tests to incorporate in your test and inspection process? Looking to find out more about where the Brinell method is useful and how to calculate the results? Read on for some top tips.

When is the Brinell hardness test used?

Brinell hardness testing is a commonly used method for determining the hardness of metals and alloys.

The Brinell hardness test formula

When measuring hardness using the Brinell method, a hardened steel or carbide ball of known diameter under a known load is forced into the material being tested. The diameter of the indentation is then measured, and the result indicates the hardness of the sample.

There is a formula that can help you calculate the hardness of a material based on the Brinell method. It is:

BHN = 2 P / (π D (D – (D2 – d2)1/2))


BHN = Brinell hardness number

P = the load on the indenting tool (kg)

D = the diameter of steel ball (mm)

d = measure diameter at the rim of the impression (mm)

Brinell hardness numbers can also often be expressed as BH.

Brinell hardness test charts

The approximate Brinell number for loads are:

Load (kg)Brinell hardness number
50026 – 100
150080 – 300
3000160 – 600

While the Brinell hardness test is most commonly used to test metals and alloys, it can be used on other materials too.

Typical Brinell hardness numbers include:

MaterialBrinell hardness number
Pure aluminum15
Soft brass60
Hardened aluminum75
Mild steel130
Annealed chisel steel235
White cast iron415
Nitrided surface750

The Brinell test is often carried out instead of or alongside Rockwell hardness testing and/or Vickers testing. You can find out more about this alternative method in our guide to Rockwell hardness testing.

Hardness testing solutions at Industrial Physics

For all the hardness testing systems you need, whether it’s a hardness pen for testing on the go or a Universal Testing Machine as an addition to your static set up, we’ve got you covered.

With almost 100 years of experience in the testing and inspection sector, we’re the best people to help you find the right machine for the job. If you’d like to hear more about the ways we can help, get in touch.