Weld Test; Troubleshooting - Miller Multimatic 220 AC/DC Owner's Manual

13-12. Weld Test

3
2 To 3 in.
(51-76 mm)
1/4 in.
(6.4 mm)

13-13. Troubleshooting

Possible Causes
Arc length too long.
Damp electrode.
Workpiece dirty.
Possible Causes
Amperage too high for electrode.
Arc length too long or voltage too high.
Possible Causes
Insufficient heat input.
Improper welding technique.
Workpiece dirty.
2 To 3 in.
(51-76 mm)
2
2
1
Porosity − small cavities or holes resulting from gas pockets in weld metal.
Remedy
Reduce arc length.
Use dry electrode.
Remove all grease, oil, moisture, rust, paint, coatings, slag, and dirt from work surface before
welding.
Excessive Spatter − scattering of molten metal particles that cool to solid form near weld bead.
Remedy
Decrease amperage or select larger electrode.
Reduce arc length or voltage.
Incomplete Fusion − failure of weld metal to fuse completely with base metal or a preceeding
weld bead.
Remedy
Increase amperage. Select larger electrode and increase amperage.
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.
Remove all grease, oil, moisture, rust, paint, coatings, slag, and dirt from work surface before
welding.
1 Vise
2 Weld Joint
3 Hammer
Strike the weld joint in the direction shown. A good weld
bends over but does not break.
If the weld breaks, examine it to determine the cause.
If the weld is porous (many holes), the arc length was
3
probably too long.
If the weld contains bits of slag, the arc may have been
too long or the electrode was moved incorrectly which
allowed molten slag to be trapped in the weld. This may
happen on a V-groove joint made in several layers and
calls for additional cleaning between layers.
If the original beveled surface is visible the material was
1
not fully melted which is often caused by insufficient
heat or too fast a travel speed.
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