PROCESS OF 0XYFUEL CUTTING
Oxy-fuel cutting is a thermal cutting process that uses oxygen and fuel gas (such as acetylene,
propane, MAPP, propylene and natural gas) to cut through materials.
The oxyfuel process is the most widely applied industrial thermal cutting process because it can cut
thicknesses from 0.5mm to 250mm, the equipment is low cost and can be used manually or
mechanised. There are several fuel gas and nozzle design options that can significantly enhance
performance in terms of cut quality and cutting speed.
Mechanised oxyacetylene cutting system
Process fundamentals
The cutting process is illustrated in Fig. 1. Basically, a mixture of oxygen and the fuel gas is used to
preheat the metal to its 'ignition' temperature which, for steel, is 700°C - 900°C (bright red heat) but
well below its melting point. A jet of pure oxygen is then directed into the preheated area instigating
a vigorous exothermic chemical reaction between the oxygen and the metal to form iron oxide or
slag. The oxygen jet blows away the slag enabling the jet to pierce through the material and continue
to cut through the material.
Fig.1. Diagram of oxyacetylene cutting process
OXYFUEL CUTTING PROCESS ADVANTAGES AND DISADVANTAGES
Process
Advantages
Disadvantages
Oxy-fuel
Low capital cost
Primarily limited to mild and low alloy steels
No electrical requirements
Less suitable for stainless steels and aluminium
Consumable costs low
Wide HAZ
Can be used manually or mechanised
Quality influenced by parameters and torch nozzle
and plate surface condition
Transportable
Can be used to cut thick sections
All positions
APPLICATION OF OXYFUEL CUTTING
Rough-cut gear wheel cut by oxyacetylene
Oxyfuel is one of the most widely used cutting processes with the following benefits:

Low cost equipment

Basic equipment suitable for cutting, gouging and other jobs such as welding and heating

Portable, suitable for site work

Manual and mechanised operations

Mild and low alloy steels (but not aluminium or stainless steel)

Wide range of thickness (typically from 1mm to 1000mm)
1.
Acetylene
common cutting
2.
Propane
For smooth cut edge, less slag adhesion and lower plate edge hardening because of the lower flame
temperature. The heat affected zone is much wider than for oxyacetylene.
3.
MAPP
for cutting in deep water.
4.
Propylene
producing faster cuts
5.
Methane
for piercing.