Tweco 100 Weldskill - Manual (Page 30)

weldskill 100 iNVeRTeR
4-8 March 3, 2008
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 Ferrocraft 21 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 10° from
the horizontal to enable a good bead to be
deposited. Refer Figure 4-16. 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
4-17 illustrates multi-run technique and Figure
4-18 shows the effects of pausing at the edge
of weave and of weaving too rapidly.
Art # A-07701
Figure 4-16: Single run vertical fillet weld
Art # A-07702
Figure 4-17: Multi run vertical fillet weld
Art # A-07703
Figure 4-18: Examples of vertical fillet welds
2. Vertical Down
The Ferrocraft 21 electrode makes welding in
this position particularly easy. Use a 3.2mm
electrode at 100 amps. The tip of the electrode
is held in light contact with the work and the
speed of downward travel is regulated so that
the tip of the electrode just keeps ahead of the
slag. The electrode should point upwards at
an angle of about 45°.
3. Overhead Welds
Apart from the rather awkward position
necessary, overhead welding is not much
more difficult that downhand welding. Set up a
specimen for overhead welding by first tacking
a length of angle iron at right angles to another
piece of angle iron or a length of waste pipe.
Then tack this to the work bench or hold in a
vice so that the specimen is positioned in the
overhead position as shown in the sketch. The
electrode is held at 45° to the horizontal and
tilted 10° in the line of travel (Figure 4-19). The
tip of the electrode may be touched lightly on
the metal, which helps to give a steady run. A
weave technique is not advisable for overhead
fillet welds. Use a 3.2mm Ferrocraft 12XP
electrode at 100 amps, and deposit the first
run by simply drawing the electrode along at
a steady rate. You will notice that the weld
deposit is rather convex, due to the effect of
gravity before the metal freezes.
Art # A-07704
Figure 4-19: Overhead fillet weld