CAUSES AND REMEDIES FOR FUSION WELD DISCONTINUTIES

	CAUSES	CORRECTIVE ACTION
A.	POROSITY
1.	Contamination of work piece	Clean joint area
2.	Excessive moisture pickup in electrode covering	Follow manufacturers recommended rebaking procedure.
3.	Moisture on work surfaces	Use preheating/warm up work piece.
4.	High Sulphur content	Use basic coated base metal electrodes.
5.	a) A long arc length b) Excessive current c)Higher travel speed	Change welding parameters and technique.
6.	High solidification rate	Use preheat Increase heat input.
B.	INCLUSIONS
1.	Improper cleaning procedure	Clean work surfaces and each weld run throughly. Whereever necessary use power wire brush, grinders, chisel to ensure through removal of slag.
2.	Improper welding technique a) Long arc length b) High travel speed c) Slag flooding ahead of welding arc.	Improve welding technique. Reposition work to prevent loss of slag control wherever possible Restrict weaving to minimum
3.	Narrow, inaccessible joints	Increase groove angle.
C.	INCOMPLETE FUSION
1.	Improper joint design	Increase includes angle of groove joint. Change the groove design to 'J' or a 'U' type
2.	Presence of slag or oxide film	Clean weld surfaces prior to welding.
3.	Incorrect electrode position and operating current	Maintain proper electrode position and current.
4.	Improper manipulation of arc	Use correct manipulation techniques to melt the joint faces properly.
D.	INADEQUATE PENETRATION
1.	Improper joint preparation. a) Excessively thick root face. b) Insufficient root opening c) Bridging of root opening	Use proper joint geometry. Reduce root face height. Use wider root opening.
2.	Electrode diameter too large	Use smaller electrode in root. Increase root opening.
3.	Inadequate current	Follow correct welding current and technique.
E.	CRACKS
1.	High rigidity of joint	Use preheating Relieve residual stresses minimises shrinkage stresses, using backstep or block welding sequences.
2.	Poor joint fit up	Adjust root opening all alignment.
3.	Higher carbon content of weld metal and/or hardenable base material	Use proper electrode. Use buttering layers wherever necessary.
4.	Too small a weld bead	Decrease travel speed to increase cross section of bead. Increase electrode size.
5.	High sulphur content in base level of sulphur of weldmetal element like Mn.	Use filler with high level of sulphur fixing element like Min.
6.	Hot cracking	Reduce the heat input. Minimum joint restraints.
7.	Cracking at the crater	Filling up the crater before withdrawing the electrode. Use taper poer control device. Use back step welding technique.
8.	High hardenablity	Preheat the job. Post weld heat treatment without cooling to room temperature.
9.	Hydrogen induced cracking/Delayed cracking	Use low hydrogen welding electrode. Use suitable preheat and post weldheat treatment.
10.	Presence of brittle phases in the micro-structure of the base material	Soften the material before welding
11.	Low ductility of the base material	Use preheat Anneal the base metal. Use ductile weldmetal.
12.	High residual stresses	Redesign the weldmetal and reduce restraints. Change welding sequence. Use intermediate stress-relief heat treatment.
13.	Excessive dilution	Change welding current. Use buttering technique wherever possible.