Tweco 300 ACDC Arcmaster - Manual (Page 50)

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4 Portions of the weld
run do not fuse to the
surface of the metal
or edge of the joint.
A
B
Small electrodes used on
heavy cold plate.
Welding current is too low.
A
B
Use larger electrodes and pre-heat
the plate.
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.
Table 10-2 (continued). STICK Welding Problems
Figure 10-2. Example of Lack of Fusion
5 Non-metallic particles
are trapped in the
weld metal (slag
inclusion).
A Non-metallic particles may be
trapped in undercut from
previous run.
A If bad undercut is present, clean
slag out and cover with a run from
a smaller diameter electrode.
B Joint preparation too restricted. B Allow for adequate penetration and
room for cleaning out the slag.
C Irregular deposits allow slag to
be trapped.
C If very bad, chip or grind out
irregularities.
D Lack of penetration with slag
trapped beneath weld bead.
D Use smaller electrode with
sufficient current to give adequate
penetration. Use suitable tools to
remove all slag from corners.
E Rust or mill scale is preventing
full fusion.
E Clean joint before welding.
F Wrong electrode for position in
which welding is done.
F Use electrodes designed for
position in which welding is done,
otherwise proper control of slag
is difficult.
Table 10-2 (continued). STICK Welding Problems
Figure 10-3. Examples of Slag Inclusion