BRINELL HARDNESS TESTING

DEFINITION OF THE BRINELL HARDNESS TEST

The Brinell hardness test was originally developed in the late 1800s by the Swedish engineer of the same name. He wanted to find a method to control the quality/hardness of steel. His solution was to press a railway wheel-bearing ball into the material and then measure the size of the mark it left. The method proved reliable and in 1900 the Brinell hardness test was officially born.

Today, the Brinell test is performed using a Brinell hardness test unit. The machine presses a tungsten carbide ball into the sample, and then optically measures the diameter of the impression.

• Indenter sizes: 1, 2.5, 5 and 10 mm
• Loads: From 1 kgf to 3000 kgf
• Maximum hardness: 650 HBW

A hardness test for larger samples

As the Brinell hardness test (HBW) indentation leaves a relatively large impression, the Brinell hardness test is better suited to larger samples with a coarse or inhomogeneous grain structure, such as castings and forgings.

Good to know

HBW stands for Hardness Brinell Wolfram carbide. Wolfram carbide (= tungsten carbide) underlines that newer Brinell standards call for the use of tungsten carbide balls, as opposed to the (softer) steel balls previously used (HBS). Values will differ at higher hardness.

The most common Brinell hardness test methods

There are a number of common Brinell hardness test methods, with corresponding materials and hardness ranges. Most test methods can be performed on any Brinell hardness testing machine.

The Brinell methods are generally divided into four subgroups (HB30, HB10, HB5, HB2.5), each suitable for a different group of materials.

• Each subgroup has the same force/diameter ratio (F/D²)
• Measured Brinell hardnesses can only be compared within individual subgroups

* Materials mentioned in the table are examples of typical materials only.

Explanation

• HBW 2.5/187.5: Brinell 2.5 mm tungsten carbide ball and 187.5 kgf load.
• HBW 5/750: Brinell 5.0 mm tungsten carbide ball and 750 kgf load.