©
COPYRIGHT 1998 THE ESAB GROUP, INC. LESSON
II 2.5
FLUX CORED ARC WELDING
Flux
Cored Arc Welding (FCAW) is quite similar
to GMAW as far as operation and equipment
are concerned. The major difference is that FCAW utilizes an electrode that
is very different
from the solid electrode used in GMAW. The flux cored electrode is a fabricated
electrode and as the name implies,
flux material is deposited into its core. The flux cored
electrode begins as a flat metal strip
that is formed first into a "U" shape. Flux and alloying
elements are deposited into the "U"
and then the shape is closed into a tubular configuration
by a series of forming rolls.
2.5.0.1 The
flux cored electrode is a continuous electrode that is fed into the arc where
it is melted and
transferred into the molten puddle. As in GMAW, the flux cored process depends
on a gas shield to protect the weld
zone from detrimental atmospheric contamination. With
FCAW, there are two primary ways this
is accomplished (See Figure 18). The gas is either
applied externally, in which case the
electrode is referred to as a gas shielded flux cored electrode,
or it is generated from the decomposition of gas forming ingredients contained
in the electrode's
core. In this instance, the electrode is known as a self-shielding flux
cored electrode.
In addition to the gas shield, the flux cored electrode produces a slag
covering for further
protection of the weld metal as it cools. The slag is manually removed with
a wire brush or
chipping hammer. 2.5.1
Self
Shielded Process
- The main advantage of the self shielding method is
that its
operation is somewhat simplified because of the absence of external shielding
equipment. FIGURE
18 GAS CUP
GAS SHIELD FLUX
CORE GAS SHIELDED
CONTACT TIP INSULATED
GUIDE TUBE SELF
SHIELDED CONTACT
TIP FLUX CORE
FLUX-CORED ARC WELDING
