Page 113 - CITS - Welder - Trade Practical

WELDER - CITS

• Fix nozzle No. 5 on the blow pipe and adjust gas pressure of 0.15 kg/sq.cm2 for both gases.
• Adjust a strict neutral flame. (Fig 2)

Fig 1 Fig 2

• Use silicon aluminium filler rod 3 mm ø and apply the pasty flux on the filler rod.
• Tack-weld at both ends of the joint and at the centre.
• Preheat the job to a temperature of 150° - 180°C to reduce the effect of expansion during welding using the
blow pipe flame itself.
• Start welding by the leftward technique by holding the blowpipe at an angle of 40° to 50° and the filler rod at
an angle of 30° - 40°. (Fig 3)

Fig 3

• Do not remove the filler rod end from the outer envelope of the flame till the welding is over.
• Clean the weld by washing in a 10% sulphuric acid solution.

• Again, wash the weld by rinsing in hot or cold water.
• No traces of flux should remain on the weld. It will cause corrosion, after completion of the weld.
• Inspect for weld defects.
• As the end of the joint is approached, reduce the blow pipe and filler rod angle and raise the inner cone. This
is done to avoid burn through of the joint.

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CITS : C G & M - Welder - Exercise 21