Page 110 - CITS - Welder - Trade Practical
P. 110

WELDER - CITS


           EXERCISE 20 : Square butt and lap joint on M.S. sheet

                                     2mm thick by brazing in flat position (OAW)


            Objectives

           At the end of this exercise you shall be able to
           •  braze an M.S. square butt joint using oxidizing flame and brazing filler rod and flux
           •   remove the surface oxide and other impurities with wire wool
           •   select nozzle, filler rod, flux and flame for brazing
           •   clean the joint and inspect for surface defects.











































           Job Sequence

           •  Cut the sheets as per drawing and file the edges to be joined square.
           •   Clean the joint area.

           •   Set the sheets as a square butt joint without root gap
           •   Select nozzle, filler rod, gas pressures, flux.
           •   Set oxidizing flame.
           •   Use leftward technique.

           •   Preheat the sheets and joint area to about 800°C.
           •  Dip the hot filler rod in flux and melt the filler rod into the joint ensuring proper wetting conditions.
           •   Avoid application of too much heat into the joint.
           •   Finish the joint in one run only.



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