Introduction
Incomplete
Penetration
Lack of
Longitudinal
Undercutting
Fusion
Porosity
Cracking

 

 

 

Variations-
Metal
Transfer
Equipment
Power
Supply
Shielding
Gases
Wire
Electrodes
Safety
Welding
Techniques
Welding
Conditions
Economics
Weld
Defects
Mig Spot
Welding
Tables

 

2 INCOMPLETE PENETRATION This type of defect is found in any of three ways: 1)   When the weld bead does not penetrate the entire thickness of the base plate. 2)   When two opposing weld beads do not interpenetrate. 3)   When the weld bead does not penetrate the toe of a fillet weld but only bridges across it. Welding current has the greatest effect on penetration. Incomplete penetration is usually caused by the use of  too low a welding current and can be eliminated by simply increasing the amperage. Other causes can be the use of too slow a travel speed and an incorrect torch angle. Both will allow the molten weld metal to roll in front of the arc, acting as a cushion to prevent penetration. The arc must be kept on the leading edge of the weld puddle. Figure 10-1 - Examples of Lack of Penetration