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Making Welded Joints
Having attained some skill in the handling of an
electrode, you will be ready to go on to make up
welded joints.
A. Butt Welds
Set up two plates with their edges parallel, as
shown in Figure 1-21, allowing 1.6mm to 2.4mm
gap between them and tack weld at both ends. This
is to prevent contraction stresses from the cooling
weld metal pulling the plates out of alignment.
Plates thicker than 6.0mm should have their mating
edges beveled to form a 70º to 90º included angle.
This allows full penetration of the weld metal to
the root. Using a 3.2mm E7014 Stick electrode
at 100 amps, deposit a run of weld metal on the
bottom of the joint.
Do not weave the electrode, but maintain a steady
rate of travel along the joint sufficient to produce a
well-formed bead. At first you may notice a
tendency for undercut to form, but keeping the arc
length short, the angle of the electrode at about
20º from vertical, and the rate of travel not too fast,
will help eliminate this.
The electrode needs to be moved along fast
enough to prevent the slag pool from getting
ahead of the arc. To complete the joint in thin
plate, turn the job over, clean the slag out of the
back and deposit a similar weld.
Butt Weld
o
o
20
- 30
(Fig 1-21)
Electrode
Tack Weld
Weld Build Up Sequence
(Fig 1-22)
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.
Electrode Position
for HV Fillet Weld
(Fig 1-23)
A piece of angle iron is a suitable specimen with
which to begin, or two lengths of strip steel may
Tack Weld
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.
o
45
from
vertical
o
o
60
-70
from
line of weld
11
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