Figure 15-23.Portable oxyacetylene welding and cutting equipment.
Oxyacetylene welding is a gas welding process. A
coalescence or bond is produced by heating with a gas
flame or flames obtained from the combustion of
acetylene with oxygen, with or without the application
of pressure, and with or without the use of filler metal.
A welding torch is used to mix the gases in the proper
proportions and to direct the flame against the parts to
be welded. The molten edges of the parts then literally
flow together and, after cooling, form one solid piece.
Usually, it is necessary to add extra material to the joint.
The correct material in rod form is dipped in and fuses
with the puddle of molten metal from the parent metal
Acetylene is widely used as the combustible gas
because of its high flame temperature when mixed with
oxygen. The temperature, which ranges from
approximately 5,700° to 6,300°F, is so far above the
melting point of all commercial metals that it provides
a means for the rapid, localized melting essential in
welding. The oxyacetylene flame is also used in cutting
ferrous metals. The oxyacetylene welding and cutting
methods are widely used by all types of maintenance
activities because the flame is easy to regulate, the gases
may be produced inexpensively, and the equipment can
be transported easily and safely.
Oxyacetylene Welding Equipment
The equipment used for oxyacetylene welding
consists of a source of oxygen and a source of acetylene
from a portable or stationary outfit. The portable outfit
consists of an oxygen cylinder and an acetylene cylinder
with attached valves, regulators, gauges, and hoses
(fig. 15-23). This equipment may be temporarily
secured on the floor or mounted on a two-wheel, welded,
steel truck equipped with a platform that will support
two large size cylinders. The cylinders are secured by
chains attached to the truck frame. A metal toolbox,
welded to the frame, provides storage for torches, tips,
gloves, fluxes, goggles, and necessary wrenches.
Stationary equipment is installed where welding
operations are conducted in a fixed location. The
acetylene and oxygen are piped to several welding
stations from a central supply. Master regulators are
used to control the flow of gas and maintain a constant
pressure at each station.
OXYGEN.Oxygen is a colorless, tasteless, odor-
less gas that is slightly heavier than air. Oxygen is