Firepower MST 220i, Руководство по эксплуатации

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FIREPOWER MST 220i
BASIC WELDING 4-12 Manual 0-5343
Art # A-07698
Figure 4-22: Weld Build up Sequence
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 de-
posited using either a weave technique or single
beads laid down in the sequence shown in Figure
4-22. 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
4-24.
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 1/8" (3.2
mm) E7014 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 to be sloped about 20º away from the per-
pendicular position to prevent slag from running
ahead of the weld. Refer to Figure 4-23. Do not
attempt to build up much larger than 1/4" (6.4 mm)
width with a 1/8" (3.2 mm) 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 4-24. Weaving in HV
fillet welds is undesirable.
Art # A-07699_AB
45° from
vertical
60° - 70° from line
of weld
Figure 4-23: Electrode Position for HV Fillet Weld
Art # A-07700_AB
1
2
3
4
5
6
Figure 4-24: Multi-runs in HV Fillet Weld
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 1/8"
(3.2 mm) E7014 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 Figure 4-25. Use a short arc,
and do not attempt to weave on the first run.
When the first run has been completed de-slag
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
4-26 illustrates multi-run technique and Figure
4-27 shows the effects of pausing at the edge
of weave and of weaving too rapidly.