Excessive Spatter; Incomplete Fusion; Lack Of Penetration - Miller Shielded Metal Arc Welding Manuallines

4-2. Excessive Spatter

Possible Causes
Amperage too high for Decrease amperage or select larger electrode.
electrode.
Arc length too long or voltage Reduce arc length or voltage.
too high.

4-3. Incomplete Fusion

Possible Causes
Insufficient heat input. Increase amperage. Select larger electrode and increase amperage.
Improper welding technique. Place stringer bead in proper location(s) at joint during welding.
Adjust work angle or widen groove to access bottom during welding.
Momentarily hold arc on groove side walls when using weaving technique.
Keep arc on leading edge of weld puddle.
Workpiece dirty. Remove all grease, oil, moisture, rust, paint, coatings, slag, and dirt from work surface before welding.

4-4. Lack Of Penetration

Lack of Penetration
Possible Causes
Improper joint preparation. Material too thick. Joint preparation and design must provide access to bottom of groove.
Improper weld technique. Keep arc on leading edge of weld puddle.
Reduce travel speed.
Insufficient heat input. Increase amperage. Select larger electrode and increase amperage.
Excessive Spatter − scattering of
molten metal particles that cool to
solid form near weld bead.
Incomplete Fusion − failure of weld
metal to fuse completely with base
metal or a preceeding weld bead.
Lack Of Penetration − shallow
fusion between weld metal and
base metal.
Good Penetration
Corrective Actions
Corrective Actions
Corrective Actions
155 095 Page 21
www.manaraa.com