Page 113 - CITS - Welder - Trade Practical
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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
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