Page 34 - CITS - Welder - Trade Practical

WELDER - CITS

Skill Sequence

Setting the gas cutting plant

Objectives: At the end of this exercise, you shall be able to
• set the work pieces for bevel cutting
• gas cut bevel surfaces by hand
• inspect the bevel cut.

Set the oxy-acetylene gas cutting plant in the same way as was done for welding and connect the cutting blowpipe
in the place of the welding blowpipe. (Fig 1) Also change the oxygen welding regulator with oxygen cutting
regulator.
Setting the job for straight line cutting of Triangular shape (Fig 2): Mark and punch straight lines on the plate.

Fig 1 Fig 2

Set the job on the cutting table so that the parting piece is free to fall.
Note: Ensure that the underside of the cutting line is clear and no combustible materials are lying
nearby.
Adjusting cutting flame: Select the cutting nozzle and set the gas pressure as per the cutting job thickness.
(Table1)
TABLE 1

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
Data for cutting
Acetylene pressure should be 0.15 kgf/cm2 for all thickness of plates.

Select 0.8 mm ø cutting oxygen (orifice) nozzle for cutting a 6 mm thick plate.
Set 1.4 kg/sq.cm pressure for the cutting oxygen and 0.13 kg/sq.cm pressure for the acetylene gas.

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CITS : C G & M - Welder - Exercise 04