What are defects or faults of welding ?

• Acts as stress riser from which a crack may propagate

Cause –

• Root gap too small
• high welding speed
• Low heat input
• Too large electrode dia

Prevention:  

• Proper joint preparation
• Proper heat input & welding speed
• Use suitable size of electrode
  

  LACK OF FUSION

“Lack of complete melting/ fusion of some portion of the weld metal in a joint”

• May be at the root, sides or between two runs.

• Reduces the strength of welds & makes welded structures unreliable.

Cause:

• Low welding current
• Excess welding speed
• Unfavourable heat input

Prevention:

• Maintain proper current & welding speed
• Proper cleaning of each bead.
  

  Slag inclusion-

Metallic or nonmetallic solid material entrapped within the WM, between weld passes or between WM & BM”.