Rockwell Hardness Test

Introduction:

The term 'hardness' refers to the resistance of a metal to permanent deformation to its surface. This deformation may be in the form of scratching, mechanical wears, indentation or cutting. Depending on the particular deformation type (or for that matter particular type of stressing) hardness may be of the following types: 
i.        Indentation hardness test (by indenting) 
ii.      Scratch hardness test (by scratching) 
iii.    Dynamic hardness test (by impact) 
iv.    Rebound hardness test (by the rebound of a falling ball)

Hardness has correlation with other mechanical properties of the material; thus hardness tests have wide application as a non-destructive test of metals.