Rockwell Indentation Hardness Test

1
Rockwell Indentation Hardness Test
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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

• 300-124 76
• i.e.
• 76 HR C

Hardness value
Rockwell Hardness
Rockwell C Scale