Hardness is the property of a material that enables it to resist plastic deformation, penetration, indentation, and scratching. Therefore, hardness is important from an engineering standpoint because resistance to wear by either friction or erosion by steam, oil, and water generally increases with hardness
Hardness testing plays a vital role in materials testing, quality control, and acceptance of components. The data is needed in order to verify the heat treatment, structural integrity, and quality of components that will help to determine if a material has the properties essential for its proposed use.