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Welder’s Handbook
Slag Inclusions
Cause
Prevention
Slag Inclusions
Clean surface and previous weld bead
Entrapment of refractory oxides
Power wire brush the previous weld bead
Tungsten in the weld metal
Avoid contact between the electrode and the work; use larger electrode
Improper joint design
Increase groove angle of joint
Oxide inclusions
Provide proper gas shielding
Slag flooding ahead of the welding arc
Reposition work
Poor Electrode manipulative technique
Change electrode or flux
Entrapped pieces of electrode covering
Use undamaged electrodes
Effects
The presence of slag causes concentrated stress which reduces the durability and productivity of the weld metal.
Corrective Action
Completely remove slag from all intermediate weld areas. Remove all loose slag with a needle gun or chipping hammer? Grind all tightly adhering, unacceptable slag from the surface of the base material or weld.
Inspection & Standards
Radiography Test (RT) Incomplete fusion will be detected as a thin, dark line with sharply defined edges. based on how the defect aligns with the X-ray beam's orientation, the line may tend to be wavy and diffuse
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