41
10.02 MIG Welding Problems
Description
Possible Cause
Remedy
1 Undercut.
A Welding arc voltage too high.
A Reduce
WELD (V) control or increase the wire
feed speed.
B Incorrect torch angle.
B Adjust angle.
C Excessive heat input.
C Increase the torch travel speed and/or reduce
welding current by reducing the
WELD (V)
control or reducing the wire feed speed.
2 Lack of penetration. A Welding current too low.
A Increase welding current by increasing wire
feed speed and increasing
WELD (V) control.
B
Joint preparation too narrow or gap
too tight.
B Increase joint angle or gap.
C
Shielding
gas
incorrect.
C Change to a gas which gives
higher penetration.
3 Lack of fusion.
Voltage too low.
Increase
WELD (V) control.
4 Excessive spatter.
A Voltage too high.
A Lower the voltage by reducing the
WELD (V)
control or increase wirespeed control.
B Voltage too low.
B Raise the voltage by increasing the
WELD (V)
control or reduce wirespeed control.
5 Irregular weld
shape.
A Incorrect voltage and current
settings. Convex, voltage too low.
Concave, voltage too high.
A Adjust voltage and current by adjusting the
WELD (V) control and the wirespeed control.
B Wire is wandering.
B Replace contact tip.
C Incorrect shielding gas.
C Check shielding gas.
D
Insufficient
or
excessive heat input.
D Adjust the wirespeed control or the voltage
selection switches.
6 Weld cracking.
A Weld beads too small.
A Decrease travel speed.
B Weld penetration narrow and deep.
B Reduce current and voltage and increase MIG
torch travel speed or select a lower
penetration shielding gas.
C Excessive weld stresses.
C Increase weld metal strength or
revise design.
D
Excessive
voltage.
D Decrease voltage by reducing the
WELD (V) control.
E Cooling rate too fast.
E Slow the cooling rate by preheating part to be
welded or cool slowly.
7 Cold
weld
puddle.
A
Faulty rectifier unit.
A
Have an accredited Thermal Arc Service Agent
to test then replace the faulty component.
B
Loose welding cable connection.
B
Check all welding cable connections.
C
Low Primary Voltage.
C
Contact supply authority.
