Enter your test load (P), ball diameter (D), and indentation diameter (d) to calculate the Brinell Hardness Number (BHN) of a material. The calculator applies the standard Brinell hardness formula and returns the BHN value along with the indentation surface area — useful for metallurgy, material science, and quality testing applications.
Brinell Hardness Number (BHN)
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Indentation Surface Area
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Test Load
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Indentation Depth (h)
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The Brinell Hardness Number (BHN or HBW) is a numerical value representing the indentation hardness of a material. It is determined by pressing a hard spherical ball into the material under a known load and measuring the diameter of the resulting indentation. A higher BHN indicates a harder material.
The Brinell hardness test is a standardized non-destructive method for measuring material hardness, developed by Swedish engineer Johan August Brinell in 1900. It involves pressing a steel or tungsten carbide ball of a known diameter into the surface of a material under a specified load for a set time, then measuring the indentation diameter.
BHN is calculated using the formula: BHN = 0.102 × (2P) / (π × D × (D − √(D² − d²))), where P is the applied load in kgf, D is the ball diameter in mm, and d is the indentation diameter in mm. The denominator represents the curved surface area of the spherical indentation.
The Brinell hardness number for copper typically ranges from 35 to 100 HBW depending on its temper and alloy composition. Pure annealed copper is around 35 HBW, while cold-worked or alloyed copper can reach values closer to 100 HBW.
Aluminum alloys generally have a Brinell hardness number between 15 and 150 HBW. Pure aluminum is very soft at around 15–20 HBW, while high-strength aluminum alloys (such as 7075-T6) can reach 150 HBW or higher.
The Brinell hardness test is widely used in metallurgy, manufacturing quality control, and materials engineering. It is particularly suited for testing castings, forgings, and rough-surfaced materials where other hardness tests may be less practical due to the relatively large indentation area.
BHN (Brinell Hardness Number) and HBW refer to the same measurement. The modern ISO and ASTM standards use HBW specifically when a tungsten carbide (W = Wolfram) ball is used as the indenter, which is now the standard. The older HBS designation referred to steel ball indenters, which are no longer recommended for most applications.
The Brinell test is not suitable for very hard materials (above ~650 HBW) because the ball indenter may deform. It also requires a relatively thick and flat specimen due to its large indentation size, and the indentation measurement must be done carefully with an optical microscope for accurate results.