macrohardness

Macrohardness is a cross-disciplinary term used to describe the hardness of a material measured at a macroscopic scale, with tests that produce indentations visible to the naked eye. It is commonly considered the bulk hardness of a material, as opposed to microhardness tests that probe small volumes and are sensitive to local microstructural features.

In practice, macrohardness is determined using standard hardness tests such as Brinell, Rockwell, and certain polymer-focused durometer methods. Brinell testing uses a relatively large indenter (usually a ball) pressed into the surface under high load, and the hardness value is derived from the indentation diameter. Rockwell testing uses a diamond cone or a spherical indenter with predefined loads, yielding a numerical hardness on a categorical scale (for example, HRB, HRC). For polymers and some elastomers, Shore durometer tests (Shore A, Shore D) are commonly employed. Macrohardness values are traditionally reported as numbers with the relevant scale (HB, HRC, HRB, or Shore D, etc.).

Hardness generally correlates with some bulk mechanical properties, particularly strength and wear resistance, but with notable limitations. It provides a quick, relatively inexpensive proxy for material performance, especially for screening and quality control. However, hardness is not a direct measure of ductility, toughness, or fracture resistance, and results can be influenced by surface finishing, residual stresses, and heat treatment history.

Standards from organizations such as ISO and ASTM govern macrohardness testing procedures and calibration, ensuring consistency across materials, indenter types, loads, and measurement methods.