Oxy-hydrogen welding is a gas welding process that uses a torch to produce a flame from burning oxygen and hydrogen gases. The gases are supplied through separate hoses and cylinders to the welding torch, where they mix and ignite to burn at the torch nozzle. By concentrating the flame's heat on the joint edges, the metals melt and fuse together to permanently join two pieces when cooled. Different types of welding flames can be produced by varying the ratio of oxygen to hydrogen to suit materials like brass, steel, or aluminum alloys.

1. Prepared By:
MayurSinh Rathod

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.

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.

10.  Welding Flame :
Oxidizing
Excess oxygen (1.5:1)
(Brasses, Bronzes, copper)
Neutral
Equal Hydrogen acetylene &
oxygen (low carbon steel,
mild steels).
Reducing or Carburizing
Excess Hydrogen (0.9:1)
(Alloy steels and
aluminium alloys)
Inner Cone
Max. Temp.
Zone