failure of the weld
metal to fill the
root of the weld
current is too low
(b) Electrode too
large for joint.
(c) Insufficient gap
(d) Incorrect
sequence
welding current
(b) Use smaller
diameter
electrode.
(c) Allow wider
gap
(d) Use correct
build-up sequence
Portions of the
weld run do not
fuse to the surface
of the metal or
edge of the joint.
(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
(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
(e) Clean surface
before welding.
Description Possible
cause Remedy
Non-metallic
particles are
trapped in the
weld metal
(slag inclusion).
.
.
(a) Non-metallic
particles may
be trapped in
undercut from
previous run
(b) Joint
preparation too
restricted
(c) Irregular
deposits allow slag
to be trapped.
(d) Lack of
penetration with
slag
trapped beneath
weld bead.
(e) Rust or mill
scale is
preventing full
fusion.
(a) If bad undercut
is present,
clean slag out and
cover with a
run from a smaller
diameter
electrode
(b) Allow for
adequate
penetration and
room for
cleaning out the
slag
(c)if very bad, chip
or grind out
Irregularities
(d) Use smaller
electrode with
sufficient current
to give
adequate
penetration. Use
suitable tools to
remove all
slag from corners
(e) Clean joint
before welding.
(f) Wrong
electrode for
position
in which welding is
done.
(f) Use electrodes
designed for
position in which
welding is
done, otherwise
proper control
of slag is difficult.
Power source problems
Description Possible
cause
Remedy
The welding arc
cannot be
established
(a) The primary
supply voltage
has not been
switched on
(b) The welding
power source
switch is switched
off
(c) Loose
connections
internally
(a) Switch on the
primary supply
voltage
(b) Switch on the
welding
Power source.
(c) Have a
qualified service
engineer repair the
connection
Maximum output
welding current
cannot be
achieved with
nominal
mains supply
voltage
Defective control
circuit
Have a qualified
service engineer
inspect then repair
the welder
Welding current
reduces when
welding
Poor work lead
connection to
the work piece
Ensure that the
work lead has
a positive
electrical
connection to the
work piece
A total loss of
power, pilot lamp
is off, no output,
the fan is not
operating
(a) Failure of input
voltage
(b) Possible over
voltage
(c) Internal fault
with the machine
(a) Re-establish
mains supply
(b) Check voltage
and if necessary
move machine to
alternative supply
(c) Have a
qualified service
engineer inspect
then repair the
welder
Fault lamp is on,
no power output.
(a) Machine
overheated
(b) Over current
state
(c) Internal fault
with machine
(a) Allow to cool
with fan running
(b) Switch off
mains power to
the machine and
re start
(c) Have a
qualified service
engineer inspect
then repair the
welder
