These Standardized Hardness Test Block are separately used to calibrate various series of Hardness Tester.

Rockwell hardness test block  (50-88)HRA.             (20-65)HRC.                     (50-100)HRB.                 (40-78)HRD.                  (83-100)HRE.                 (86-100)HRF.                 (30-94)HRG.                (65-100)HRK