1. Rockwell Indentation Hardness Test

2. Apparatus
GNEHM OM-150 Universal Hardness Tester

3. Apparatus Diagram

4. Set knob to correct load. Rockwell C test - set knob to 150kg

5. Rotate load lever to vertical position

6. Steel item prepared for testing

7. Select correct penetrating element
Rockwell C 120 degree conical diamond indenter

8. Remove existing element

9. Insert new element

10. Rotate capstan clockwise until test piece is pressed against metal stops

11. Apply preload (Rockwell C is 10kg)
Rotate load lever anticlockwise to horizontal position

12. Set outer dial Rockwell C gauge to zero
record setting, 300 in this case

13. Rotate load lever anticlockwise to vertical down position to apply the final load. An additional 90kg applies a final load of 100kg

14. Record dial reading124 in this case

15. Calculate test piece hardness
= 76
i.e.
76 HR C
Hardness value
Rockwell Hardness
Rockwell C Scale