How does the Brinell hardness test measure the hardness of steel?

The Brinell hardness test measures the hardness of steel by evaluating its resistance to permanent deformation under a localized load.12

The process involves the following steps:

• Indentation: A hardened steel or carbide ball of a known diameter is pressed into the surface of the steel specimen using a specific, known force (load).13
• Measurement: After the load is removed, the diameter of the resulting spherical indentation is measured using a microscope.3
• Calculation: The Brinell hardness number is calculated by dividing the applied load (in kilograms) by the spherical surface area of the indentation (in square millimeters). This surface area is determined based on the diameter of the ball and the depth of the impression.43

This method provides a reliable, rapid means of assessing the hardness of metals, reflecting the material's ability to resist yielding under pressure.12