Brinell Hardness Tester

The Brinell hardness tester is a materials testing instrument that presses a hardened steel or carbide ball into a metal specimen under a known load and measures the diameter of the resulting indentation to calculate a hardness number, proportional to a material's resistance to permanent deformation. The Swedish engineer Johan August Brinell devised the test and presented it at the Paris Exposition in 1900, developing it out of his work as an engineer at the Fagersta ironworks in Sweden studying how steel behaved under rolling and forging. The Brinell test became one of the first standardized, repeatable hardness measurements in industrial use, particularly suited to testing coarse-grained or heterogeneous materials such as castings and forgings because its relatively large indentation averages out local variation.