Firepower MST 180i Operating Manual page 71

FAULT
5 Portions of the
weld run do not
fuse to the surface
of the metal or
edge of the joint.
6 Gas pockets or
voids in weld
metal (porosity)
7 Crack occurring in
weld metal soon
after solidification
commences
8 The Stick elec-
trode is difficult to
run with multiple
arc-outs when
welding
Manual 0-5339
CAUSE
A Small electrodes used on
heavy cold plate.
B Welding current is too low.
C Wrong electrode angle.
D Travel speed of electrode is
too high.
E Scale or dirt on joint surface. E Clean surface before welding.
Lack of fusion caused by dirt,
electrode angle incorrect,
rate of travel too high
Art # A-05867_AC
Lack of side fusion,
scale dirt, small electrode,
amperage too low
Figure 2: Example of Lack of Fusion
A High levels of sulfur in steel. A Use an electrode that is designed for high sulfur
B Electrodes are damp.
C Welding current is too high.
D Surface impurities such as
oil, grease, paint, etc.
E Welding in a windy environ-
ment.
F Electrode damaged ie flux
coating incomplete.
A Rigidity of joint.
B Insufficient throat thickness. B Travel slightly slower to allow greater build up in
C Weld current is too high.
Not cleaned,
or incorrect
electrode
Figure 3: Example of Slag Inclusion
The Stick electrode being
used is not suitable for use
with this machine.
Table 4-6: Welding Problems - Stick (SMAW)
A Use larger electrodes and preheat the plate.
B Increase welding current.
C Adjust angle so the welding arc is directed more
into the base metal.
D Reduce travel speed of electrode.
Lack of
inter-run fusion
Lack of root fusion
steels.
B Dry electrodes before use.
C Reduce welding current.
D Clean joint before welding.
E Shield the weld area from the wind.
F Discard damaged electrodes and only use elec-
trodes with a complete flux coating.
A Redesign to relieve weld joint of severe stresses or
use crack resistance electrodes.
throat.
C Decrease welding current.
Slag
trapped in
undercut
Slag trapped in root
Art # A-05868_AC
Use E6013 or E7018 Stick electrodes for steel or
300 series stainless steel Stick electrodes for 300
series stainless steel.
4-17
Firepower MST 180i
REMEDY
BASIC WELDING GUIDE