Other weld problems can be reduced by checking the following points.
Troubleshoo ng – MIG Weld Quality
Fault
Cause
Remedy
Undercut
Figure 48
Welding arc voltage too high
Decrease voltage or increase
the wire feed speed.
Incorrect torch angle
Adjust angle.
Excessive heat input
Increase the torch travel speed
and/or
decrease
welding
current by decreasing the
voltage or decreasing the wire
feed speed.
Lack of penetra on
Figure 49
Welding current too low.
Joint prepara on too narrow or gap
too ght.
Increase joint angle or gap.
Shielding gas incorrect.
Change to a gas which gives
higher penetra on.
Lack of fusion
Figure 50
Voltage too low
Increase voltage
Excessive spa er
Figure 51
Voltage too high
Decrease voltage or increase
the Current (Wire Speed)
control
Voltage too low.
Increase
the
voltage
or
decrease Current (Wire Speed)
Irregular weld shape
Incorrect voltage and current
se ngs.
Convex, voltage too low.
Concave, voltage too high.
Adjust voltage and current by
adjus ng the voltage control
and the Current (Wire Speed)
control
Wire is wandering.
Replace contact p.
Incorrect shielding gas.
Check shielding gas.
Insufficient or excessive heat input. Adjust the Current (Wire Speed)
control or the voltage control.
Weld cracking
Figure 52
Weld bead is too small.
Decrease travel speed.
Weld penetra on narrow and deep. Reduce current and voltage and
increase MIG torch travel speed
or select a lower penetra on
shielding gas.
Excessive weld stresses.
Increase weld metal strength or
revise design.
Excessive voltage.
Decrease voltage.
Cooling rate too fast.
Slow the cooling rate by
prehea ng part to be welded or
cool slowly.
Increase welding current by
increasing wire feed speed and
increasing voltage.
Increase joint angle or gap
Change to a gas which give
5.13.3 Weld Quality Problems
21
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EZIMIG185C
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