(i) Undercut
– A too rapid rate of travel of electrode or blow pipe.
– Use of wrong electrode or blow pipe.
– It can be caused by excessive heat built up.
(ii) Slag inclusion
– Using too low current to weld.
– Using too large electrode.
– Fast metal surface can cause it.
(iii) Porosity
– Using damp or wet electrode
– Welding on dirty surface of metal like rust, grease, water etc.
(iv) Excessive penetration
– Using too high welding current.
– Slow rate of travel of electrode or blow pipe.
– Bad edge preparation or wide root gap.
– Too much concentration of heat.
