ROCKWELL HARDNESS TEST - Computer Programming

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Wednesday, March 30, 2011

ROCKWELL HARDNESS TEST


ROCKWELL HARDNESS TEST



Aim:

To determine the Rockwell hardness number for the given specimen.

Apparatus Required:

1. Rockwell hardness testing machine
2. Indentor
3. Test specimen
4. Stop watch

Procedure:

1. Identify the material of the given specimen
2. Know the major load, type of indentor and scale to be used for the given test specimen from the following table.

Sl.No.
Material type
Major load
Indentor
Scale
1
Hardened steel
150kg
Diamond cone 120ยบ
C
2
Mild steel
100kg
1.58mm dia, steel ball
B
3
Aluminum
100kg
1.58mm dia. Steel ball
B
4
Brass
100kg
1.58mm dia. Steel ball
B
5
Copper
100kg
1.58mm dia. Steel ball
B

3. Fix the indentor and place the given specimen on the anvil of the machine.
4. Select the major load from the knob available on the right of the machine.
5. Raise the anvil using the rotating wheel till the specimen touches the indentor and then slowly turns the wheel till the small pointer on the dial reaches the red mark position. Now the specimen is subjected to a minor load of 10kg.
6. Push the loading handle in the forward direction to apply the major load to the specimen and allow the load to act on the specimen for 15 seconds.
7. Release the major load by pushing the loading handle in the backward direction and keep the minor 10kg load still on the specimen.
8. Read the Rockwell hardness number either from ‘C’ or ‘B’ scale, as the case may be, directly on the dial and record it.
9. Release the minor load of 10kg by rotating the hand wheel and lowering the screw bar.
10. Repeat the experiment to obtain at least 3 different sets of observations for the given specimen by giving a gap of at least 3mm between any two adjacent indentations and 1.5mm from the edge.
11. Find the average value, which will be the rckwell hardness number for the given specimen.

Result:
The Rockwell hardness number for the given specimen = RHC ----------- (or) RHB -------
Observation:
Sl.No.
Material
Major load
Indentor
Scale
Rockwell hardness number
(RHC…… or RHB)















                                                           Average













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