HomeTechnical literature >> Differences of HRA, HRB, HRC

Differences of HRA, HRB, HRC

HRA, HRB and HRC are the testing results of Rockwell hardness. A, B and C are different standard, it is named scale A (HRA), scale B (HRB) and scale C (HRC).

Rockwell Hardness is one of the most popular hardness testing methods. The initial testing force is 98.07N (10kgf), then according to the depth of indentation to calculate the hardness value.

Scale HRA apply diamond cone indenter, then add the testing force to 588.4N (60kgf).

Scale HRB apply diameter 1.588mm(1/16inch) steel ball indenter, then add the testing force to 980.7N (100kgf).

Scale HRC apply the same indenter with HRA, but it need to add the testing force to 1471N (150kgf). So HRB is for compare software materials, while HRC is for hard materials.