Level 3 Engineering Fitter Practice Exam 2026 – The All-in-One Guide to Master Your Certification!

Hardness testing measures a material's resistance to local plastic deformation. In these tests an indenter is pressed into the surface with a defined load, and the size or depth of the resulting impression is used to quantify how hard the material is. Different methods—like Rockwell, Vickers, and Brinell—use different indenters and scales, but they all revolve around how resistant the surface is to permanent indentation. This property is distinct from elastic modulus (stiffness under elastic deformation), toughness (energy absorbed before fracture), and ductility (amount of plastic deformation before breaking). So the test specifically targets hardness—the material’s resistance to indentation.