| Defect |
Probable Cause |
| Porosity |
-Gas flow too low or too high
-Blocked nozzle
-Leaking gas lines
-Draughty conditions
-Nozzles distance from work is too great
-Painted, wet or oily plate
-Wet or rusty electrode/wire |
| Lack of penetration |
-Current too low
-Preparation too narrow
-Root face too large
-Root gap too small
-Worn contact tip causing irregular arc
-Incorrect alignment of plates |
| Spatter |
-Inadequate inductance
-voltage too low
-Rusty or primed plate |
| Undercut |
-Speed too fast
-Current too high
-Poor technique |
| Lack of fusion |
-Voltage too low
-Current too low or too high
-Irregular surface
-Wrong torch angle |
| Cracking |
-Inadequate pre-heat on high tensile and low alloys
-Incorrect composition of electrode
-Root pass too small in restrained joint
-Spray transfer welding with current too high
-Deep narrow weld bead (with centre line cracking)
-Inadequate filling of crater |
