Brinell Hardness Number Calculator

The BHN, or Brinell hardness number, is used to estimate the indentation hardness of a material sample by using the Brinell hardness number calculator. It should not be confused with the hardness of the water. An indentation experiment or a test known as the Brinell hardness test is used to calculate this hardness number.

This procedure for indentation hardness was proposed by Swedish engineer Johan August Brinell in the year 1900. Because of its non-destructive nature, the Brinell hardness test has since become a standardized test in metallurgy and material science for estimating hardness. The basic concept behind this test is to calculate pressure based on the applied force and the area of the indentation. Continue reading to learn how to use the Brinell hardness scale and how to perform a Brinell hardness test.

What is meant by Brinell Hardness Number?

The Brinell hardness test is a non-destructive test that involves pressing a small ball-shaped indentor into a material specimen with a set load value. The depth and diameter of the indentor are then recorded, and the Brinell hardness number is calculated using them.

The indentor is a D-shaped steel or tungsten carbide ball. Consider a ball indentor pressed at a force or load of P newtons. The following equation is used to calculate the Brinell hardness number:

HBW = Test Force / Surface indentation

HBW = 0.102 x 2P/ πD (D - (D^2 - d^2)^ (½))


  • P – Test force (in Newtons)
  • d – Diameter of indentation (in mm).

How do you calculate the Brinell Hardness Number?

To find the Brinell hardness number, use the following procedure:

  • Step 1: Enter the applied load P. 
  • Step 2: Enter the indentor's diameter D. 
  • Step 3: Fill in the indentation's diameter d.
  • Step 4: The surface area A, and Brinell hardness number will be determined by the calculator (HBW).

How to Perform the Brinell Hardness Test?

According to the ISO 6506-1 testing standard, the following procedure is adopted:

  • Step 1: Bring the indentor into contact with the test surface to begin the test.
  • Step 2: Apply the force parallel to the test surface, but without any shock or vibration, until the applied force meets the test standard.
  • Step 3: For a total of 14 seconds, maintain the test force. For certain materials, it could take a little longer.
  • Step 4: Remove the load and take two perpendicular measurements of the indentation's diameter.
  • Step 5: To get the Brinell hardness number, use the formula.

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Applications of Brinell Hardness Number and Similar Test

The ultimate tensile strength (UTS) of materials or alloys is often associated with the Brinell hardness scale, but this is not true for all Brinell hardness numbers. Meyer's index or law, which is an empirical relation for transforming Brinell hardness to ultimate tensile strength, can also be found online (UTS). However, It is restricted to a set of indentor diameters.

This test can be used to determine the hardness of rocks, inspect welded joints, characterize surface coatings and thin films, and determine material behavior. It's also used by scientists and engineers to create crystalline material modeling frameworks. Micro or nano indentations are some variations of this test that are commonly used, but not limited to, thin surface layers such as films and coatings.

Vickers hardness and Rockwell hardness are two other indentation tests that are similar to the Brinell hardness test and are applicable to a wide range of metals and alloys. There are also some material-specific tests, such as the Janka hardness test for wood, the Knoop hardness test for ceramics, or the Shore and Barcol hardness tests for polymers and composites.

FAQs on Brinell Hardness Number Calculator

1. What is the Brinell hardness test?

The Brinell hardness test is a non-destructive indentation test used to determine a material's hardness. It is done by impressing a small indentor onto the material surface, then measuring the diameter of the indentation to determine the Brinell hardness number.

2. For the Brinell hardness test, what indenter is used?

A hardened steel ball is used as an indenter in the Brinell hardness test. The diameter of the ball is 10 mm. In the Rockwell test, a diamond indenter is used.

3. Why are the results of the Brinell and Vickers hardness tests so similar?

The Brinell test indenter is a hardened steel indenter. Diamond is used in the Vickers test indenter. These produce indentations that are geometrically similar, resulting in similar results.

4. What is copper's Brinell hardness number?

Mild steel has a Brinell hardness rating of 35 HB. This value indicates that when a load of 500 N is applied to the material specimen using a 10 mm indentor, the user will see an indentation with a diameter of about 1.35 mm during the Brinell hardness test.

5. What's the distinction between Vickers and Brinell?

The Brinell method differs from the Vickers method in that it employs a diamond penetrating pyramid with a square base and a fixed load. The impression is measured using an optical instrument. Light test loads, as well as macro loads up to 30 kg, are possible with this technique.