2. • It is the process of joining two pieces of metal by the
application of heat or pressure or both and with or
without the use of filler metal.
3.
4. • Welding process use a flame produced by burning a
mixture of oxygen and other fuel gas.
• Generally mixer of Oxygen and Hydrogen is used
for gas welding.
• Its called Oxy-Hydrogen Welding (OHW).
5. • Separate cylinders and a hose pipe from each
cylinder transports the gases to a torch as shown in
figure.
6. Gas Pressure Regulators :
• One gauge indicates the pressure of the cylinder
and the other indicates the pressure in the supply
pipe to the torch.
7. Welding Torch :
• Oxygen and acetylene are delivered to the torch
by separate hoses. Each gas is controlled by a
valve on the torch. The two gases mix in the torch
and after they are ignited burn at the nozzle.
Mixer Needle valves
8. Filler Rods :
• Filler rods are used when additional filler metal is
required in the weld area they come in different
diameters.
9. • During the welding, heat from the flame is
concentrated on the joint edges until the metal melts.
• When the molten metal from both sides melts it
starts to fuse, when the metal cools down the two
parts become Permanently joined.
