Brinell Hardness Measurement Method

The Brinell method is a static hardness testing method, which has the following characteristics:

• It is a hardness measurement method specified by the standards ISO 6506, ASTM E
• The Brinell method has a test load range from 1 to 3000kgf, which means that this method can be used for hardness tests in low-load ranges and mainly for macroscopic measurements.
• It is an optical method. This means that the size of the indentation left by the indenter is measured to determine the hardness value of a specimen.
• The shape of the indenter is a tungsten carbide ball with a diameter of 1, 2.5, 5 or 10 mm depending on the specific method.

Operating principle

Brinell hardness (HBW) results from the quotient of the applied test force (F in newtons (N)) and the surface area of the indentation on the sample (the projection of the indentation) after withdrawal of the test force. To calculate the indentation surface area, the arithmetic mean (d) of the two perpendicular diagonals (d1 and d2 in mm) (Figure 1) is used, because the base area of Brinell indentations is often not exactly round.

Figure 1: Operating principle of Brinell hardness measurement.

Sample requirements for the Brinell method

When the Brinell hardness testing method is used, the sample must be flat and parallel. The test sample must have a flat, bare metal and smooth surface. The sample must be secured on a rigid mounting support so that it cannot move during the testing process. Normally, the sample surface must be good enough to allow correct optical evaluation of the indentation using the Brinell method.

Abbreviation explanation

• The numerical hardness value (between 26 and 800).
• The three letters "HBW" indicate Hardness Brinell (with a hard metal ball made of tungsten carbide).