Page 128 - CITS - Welder - Trade Theory

WELDER - CITS

Fig 3

The technique of welding the second layer is the same as that for the first layer.
After completion of the second layer, play the flame again on the whole job for getting an even heat. This is called
‘post heating’.

Then allow the job to cool slowly by covering with a heap of lime or ash or dry sand.
Selection of filler rod
Filler rod should be selected according to the:
a) Kind or type of metal to be welded, i.e. ferrous, non-ferrous, hard facing (Table 1) thickness of metal to be
welded (including joint edge preparation)
b) Nature of joint to be made (i.e.), fusion welding or braze welding (non-fusion)
c) Welding technique to be used (leftward or rightward).
Table 2

Metals Filler rods
Mild steel and wrought iron Copper coated mild steel (C.C.M.S)
High carbon and alloy steel High Carbon steel Silicon-manganese steel Wear-resisting alloy
steel 3.5% Nickel steel
Stainless steel Columbium stainless steel
Cast iron Super silicon cast iron Ferro silicon cast iron Nicotectic cast iron
Copper and its alloys (brass, Copper-silver alloy
bronze) Silicon-brass, silicon-bronze Nickel bronze Manganese bronze
Aluminium and its alloys Pure aluminium
5% Silicon aluminium alloy
10-13% Silicon aluminium alloy

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CITS : CG & M - Welder - Lesson 44 & 45 CITS : CG & M - Welder - Lesson 44 & 45