21
Heavy plate will require several runs to complete
the joint. After completing the first run, chip the
slag out and clean the weld with a wire brush.
It is important to do this to prevent slag being
trapped by the second run. Subsequent runs are
then deposited using either a weave technique
or single beads laid down in the sequence shown
in Figure 1-22. The width of weave should not be
more than three times the core wire diameter of
the electrode.
When the joint is completely filled, the back is either
machined, ground or gouged out to remove slag
which may be trapped in the root, and to prepare
a suitable joint for depositing the backing run. If a
backing bar is used, it is not usually necessary to
remove this, since it serves a similar purpose to the
backing run in securing proper fusion at the root of
the weld.
B. Fillet Welds
These are welds of approximately triangular cross-
section made by depositing metal in the corner of
two faces meeting at right angles. Refer to Figure
1-14, 1-23 and 1-24.
A piece of angle iron is a suitable specimen with
which to begin, or two lengths of strip steel may
be tacked together at right angles. Using a 3.2mm
E7014 Stick electrode at 100 amps, position angle
iron with one leg horizontal and the other vertical.
This is known as a horizontal-vertical (HV) fillet.
Strike the arc and immediately bring the electrode
to a position perpendicular to the line of the fillet
and about 45º from the vertical. Some electrodes
require being sloped about 20º away from the
perpendicular position to prevent slag from
running ahead of the weld. Refer to Figure 1-23.
Do not attempt to build up much larger than
6.4mm width with a 3.2mm electrode, otherwise
the weld metal tends to sag towards the base, and
undercut forms on the vertical leg. Multi-runs can
be made as shown in Figure 1-24. Weaving in HV
fillet welds is undesirable.
C. Vertical Welds
1. Vertical Up
Tack weld a three feet length of angle iron to your
work bench in an upright position. Use a 3.2mm
E7014 Stick electrode and set the current at 100
amps. Make yourself comfortable on a seat in front
of the job and strike the arc in the corner of the
fillet. The electrode needs to be about 10º from the
horizontal to enable a good bead to be deposited.
Refer Fig. 1-25.
Use a short arc, and do not attempt to weave on
the first run. When the first run has been completed
deslag the weld deposit and begin the second run
at the bottom. This time a slight weaving motion
is necessary to cover the first run and obtain good
fusion at the edges.
At the completion of each side motion, pause for a
moment to allow weld metal to build up at the
edges, otherwise undercut will form and too much
metal will accumulate in the centre of the weld.
Figure 1-26 illustrates multi-run technique and
Figure 1-27 shows the effects of pausing at the
edge of weave and of weaving too rapidly.
Electrode Position
for HV Fillet Weld
(Fig 1-23)
45
o
from
vertical
60
o
-70
o
from
line of weld
Multi-Runs in HV Fillet Weld
(Fig 1-24)
Single Run Vertical Fillet Weld
(Fig 1-25)
Weaving motion for
second and subsequent
runs
Pause at edge
of weave
Multi Run Vertical Fillet Weld
(Fig 1-26)
Summary of Contents for WeldForce WF-180MST
Page 16: ...by 16 Other weld problems can be reduced by checking the following points...
Page 23: ...23 MMA Stick Troubleshooting...
Page 26: ...by 26 TIG Welding Troubleshooting...
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