brinellering

Brinellering, or Brinell hardness testing, is a method for determining the hardness of metals by pressing a hard spherical indenter into a material surface with a defined load and measuring the resulting impression. The hardness value, Brinell hardness number (HB), reflects the material's resistance to plastic deformation.

In the procedure, a ball indenter (typically steel, sometimes carbide) with a defined diameter is pressed into the surface under a controlled force for a set dwell time (commonly 10 to 15 seconds). Ball diameters commonly used include 1, 2.5, 5 and 10 millimetres, with the 10 mm ball being most common for metals. After unloading, the diameter of the indentation is measured with a microscope or optical measurement tools.

The Brinell hardness number HB is calculated from the applied load F (in kilograms-force) and the measured indentation diameter d (in millimetres), and the ball diameter D, via the standard relation HB = 2F / (πD (D − sqrt(D^2 − d^2))). When a carbide ball is used, the value is sometimes denoted HBW; with a steel ball, HBS is used.

Standards and scope: The method is defined in international standards such as ISO 6506 and ASTM E10. It is particularly useful for materials with coarse or heterogeneous microstructures or for testing relatively large areas where a single hardness value is desirable. It is less suited for very hard or very thin materials, brittle materials, or components with complex geometry, where indentation near edges can occur.

History: The Brinell test was developed by Johan August Brinell in 1900 and remains in use in certain applications, though other hardness tests (e.g., Rockwell, Vickers) are often preferred for specific geometries or materials.