Difference Between Rockwell and Brinell hardness Testing

Hello Pal,

Main difference between Rockwell and Brinell hardness tester is principle of hardness testing. This difference in principle of Brinell and Rockwell hardness testing causes other differences like different indenter, load etc.

Difference in Rockwell and Brinell hardness:

In Brinell hardness test hard ball indenter is pressed under load on surface of material. It is there for set dwell time to achieve equilibrium, then indenter and load is withdrawn from surface. Diameter of indentation thus formed is measured. The Brinell hardness number is expressed as ratio of load and area of indentation.

The Rockwell hardness is based on difference of indentation depth of indenter from two different load applications. First minor load is applied to achieve zero level then major load is applied for specific period. Major load creates additional penetration from zero level. After dwell time major load is removed while minor load is still applied. Resulting Rockwell number is difference in depth from zero level.

Difference between Rockwell and Brinell hardness indenters /perpetrators :

Brinell: Ball Indenter e.g. 1mm, 2.5mm, 5 mm and 10 mm ball diameter.

Rockwell: Conical diamond indenter with 120° Included angle.
Ball Indenter 1/16 , 1/8 , 1/4 and 1/2 inches diameter.