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MIG WELDING PROBLEMS
Before starng any welding acvity ensure that you have suitable eye protecon and
protecve clothing. Also take the necessary steps to protect any persons within the welding
area.
MIG welding defects and prevenon methods
Defect Possible cause Acon
Burning through – Holes within the
material where no weld exists
Heat input too high Use lower amperage or smaller electrode
Use correct welding travel speed
Poor fusion – Failing of weld
material to fuse either with the
material to be welded or previous
weld beads
Insucient heat level
Poor welding technique
Work piece dirty
Increase the amperage or increase the electrode
size and amperage
Joint design must allow for full access to the root
of the weld
Alter welding technique to ensure penetraon
such as weaving, arc posioning or stringer bead
technique
Remove all contaminant from the material i.e. oil,
grease, rust, moisture prior to welding
Irregular weld bead and shape Incorrect voltage/wire feed sengs.
If its convex then the voltage is too
low and if its concave then the
voltage is too high.
Insucient or excessive heat input
Wire is wandering
Incorrect shielding gas
Adjust voltage and/or wire feed speed
Adjust the wire feed speed dial or the voltage
control
Replace contact p
Check and change the shielding gas as required
Your weld is cracking The weld beads too small
Weld penetraon narrow and deep
Excessive voltage
Weld/material cooling rate too fast
Try decreasing the travel speed
Try reducing the wire feed speed current and
voltage or increase MIG torch travel speed
Decrease voltage control dial
Slow the cooling rate by preheang part to be
welded or cool slowly
The welding arc does not have a
crisp sound that short arc exhibits
when the wire feed speed or voltage
are adjusted correctly
The MIG torch may have been
connected to the wrong output
voltage polarity on the front panel
Ensure that the MIG torch polarity lead is
connected to the posive (+) welding terminal
for solid wires and gas shielded ux cored wires
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