Page 24 - CITS - Welder - Trade Practical

WELDER - CITS

Table 1
Data for cutting

Diameter of cutting oxygen Thickness of steel plate Cutting oxygen Pressure
orifice nozzle
(1) (2) (3)
mm mm kg/cm2
0.8 3-6 1.0-1.4
1.2 6-19 1.4-2.1
1.6 19-100 2.1-4.2
2.0 100-150 4.2-4.6
2.4 150-200 4.6-4.9
2.8 200-250 4.9-5.5
3.2 250-300 5.5-5.6

Set the cutting nozzle in the blowpipe correctly. (Fig 2)

Adjust the neutral flame for preheating. (Fig 3)
Note: Ensure that the flame adjustment is not disturbed while operating the control lever for
cutting oxygen.

Straight cutting
Hold the cutting blowpipe at 900 with the plate surface, and cut along the line (Fig 4)
Preheat the starting point to red heat. (Fig 4)
Note: Keep the distance between the work piece and the nozzle about 5mm to avoid backfire. (Fig 4)

Fig 3 Fig 4

Release the extra oxygen, observe the cutting action and start travelling along the punched line at a uniform
speed. (Fig 5)
While gas cutting ensures
Note: Straight travel of the cutting blowpipe without side-to-side movement and correct
nozzle position with the plate surface till the cutting oxygen valve is fully open.
If possible, fix the straight edge to the plate, and also the spade support to ensure a straight cut (Fig 6) and to
maintain correct nozzle distance.
Inspection of gas cut (Fig 7)
Clean the gas cut with a chipping hammer, chisel and wire bunch.

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CITS : C G & M - Welder - Exercise 04