Firepower MST 140i, Operating Manual

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Firepower MST 140i
BASIC WELDING GUIDE 4-18 Manual 0-5338
FAULT CAUSE REMEDY
Insufficient Gap
Incorrect Sequence
Art # A-05866_AC
Figure 1- Example of insufficient gap or incorrect sequence
4 A groove has been
formed in the base
metal adjacent to
the toe of a weld
and has not been
filled by the weld
metal (undercut).
A Welding current is too high. A Reduce welding current.
B Welding arc is too long. B Reduce the length of the welding arc.
C Angle of the electrode is
incorrect.
C Electrode should not be inclined less than 45° to
the vertical face.
D Joint preparation does not
allow correct electrode angle.
D Allow more room in joint for manipulation of the
electrode.
E Electrode too large for joint. E Use smaller gauge electrode.
F Insufficient deposit time at
edge of weave.
F Pause for a moment at edge of weave to allow weld
metal buildup.
G Power Source is set for MIG
(GMAW) welding.
G Set Power Source to STICK (SMAW) mode.
5 Portions of the
weld run do not
fuse to the surface
of the metal or
edge of the joint.
A Small electrodes used on
heavy cold plate.
A Use larger electrodes and preheat the plate.
B Welding current is too low. B Increase welding current.
C Wrong electrode angle. C Adjust angle so the welding arc is directed more
into the base metal.
D Travel speed of electrode is
too high.
D Reduce travel speed of electrode.
E Scale or dirt on joint surface. E Clean surface before welding.
Art # A-05867_AC
Lack of
inter-run fusion
Lack of side fusion,
scale dirt, small electrode,
amperage too low
Lack of root fusion
Lack of fusion caused by dirt,
electrode angle incorrect,
rate of travel too high
Figure 2: Example of Lack of Fusion