Fault Classification And Description; Mig Welding Faults - Oerlikon CITOLINE 3500T Instrucciones De Seguridad, Empleo Y Mantenimiento

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MIG WELDING FAULTS

FAULT CLASSIFICATION AND DESCRIPTION

MIG welds may be affected by various defects, which are impor-
tant to identify. These faults do not differ in form or nature from
those encountered during manual arc welding with coated elec-
FAULT
UNEVEN LEVEL
EXCESS THICKNESS
INSUFFICIENT METAL
OXIDISED BEAD
INSUFFICIENT PENETRATION
OVER PENETRATION
LACK OF FUSION
CHANNELS
MIG WELDING FAULTS
APPEARANCE
trodes. The difference between the two applications lies rather in
the frequency of defects: porosity, for example, is more common
in MIG welding, while inclusion of slag is only encountered in
welding with coated electrodes.
The causes and prevention of faults are also quite different. The
following table illustrates the various faults.
CAUSE AND REMEDY
- Poor preparation.
- Align edges and hold during spot welding.
- No-load voltage or welding speed too low.
- Incorrect torch inclination.
- Wire diameter too large.
- Welding speed too high.
- Welding voltage too low for welding application.
- Weld in the channel if using a long arc.
- Regulate voltage.
- Wire is bent or over-protruding from the wire guide tube.
- Incorrect wire feed speed.
- Incorrect torch inclination.
- Irregular or insufficient distance.
- Wire guide tube worn.
- Wire speed too slow for voltage used or for welding speed.
- Wire speed too high.
- Incorrect torch inclination.
- Excessive distance.
- Distance too short.
- Rough out or grind the weld, then repeat.
- Welding speed too high.
(This fault is easily detected on sight by the welder, and should be correct-
ed immediately.)
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