helvi Galileo 175HF Betriebsanleitung Seite 9

- Protect your face with a mask or a helmet.
Touch, with the electrode fastened, in the
electrode holder, the work piece until the arc
will be struck. (the inverter is featuring "hot
start" to improve the striking.
Avoid hammering the workpiece with the
electrode since it may loose the coating
and increase the arc striking diffi culties.
- After striking the arc keep feeding the
electrode into the weld pool with an angle of
about 60° and moving left to right so that you
may control visually the welding. The length
of the arc can also be controlled by lifting or
lowering slightly the electrode. Also a varia-
tion of the welding angle may increase the
size of the weld pool improving the capacity
of surfacing of the slag.
- At the end of the weld let the slag cool off
before removing it, using the brush-hammer.
CAUTION:
Protect your eyes when hitting the slag
with the chip hammer to avoid damages.
CAUTION:
A bad start can be due to the dirty wor-
kpiece, a bad connection between earth
cable and work piece, or the bad faste-
ning of the electrode in the electrode
holder.
7.0 QUALITY OF THE WELD
The quality of the weld will depend mainly on
the ability of the welder, on the type of weld
and on the quality of the electrode: Choose
the proper electrode before attempting to
weld, paying attention to the thickness and
composition of the metal to be welded.
Correct welding current.
If the current is too high the elctrode will burn
fast and the weld pool will be wide irregula-
rand diffi cult to be controlled. If the current is
too low you will lack power and the weld pool
will be narrow and irregular.
Correct arc length.
If the arc is too long it will cause spatters and
small fusion of the welding piece. If the arc is
too short the arc heat will be insuffi cient cau-
sing the electrode to stick to the workpiece.
Correct welding speed.
The correct welding speed will consent to
achieve a weld of proper width, without wa-
ves or craters.
8.0 TIG WELDING
The TIG process uses the electrical arc
struck between the tungsten electrode of the
torch and the work piece surface.
In TIG welding the torch is always con-
nected to the negative pole of the welder.
Welder preparation:
- Select TIG welding thru the Selector on
the front panel.
- Connect the earth cable to the positive
pole of the welder and the earth clamp to the
work piece.
- Connect the TIG torch to the negative
pole of the welder and the gas hose to the
pressure regulator of the gas cylinder.
The fl ow of the gas is manually control-
led using the knob on the torch handle.
Use inert gas (argon ) only.
- Turn the inverter on.
9.0 TIG WELDING BY SCRATCH ARC
- Ensure the electrode at the torch nozzle,
protrudes by 4 - 5mm., also ensure that the
electrode is sharply pointed with an angle of
40°-60°.
- Set the welding current considering the
thickness of the material to be welded and of
the diameter of the tungsten electrode to be
used.
- Open the gas valve on the torch handle,
allowing gas to fl ow from the torch nozzle.
Cover your face with the head shield, bring
the torch to within 3-4mm of the work, and
at an angle of 45 °, so that the ceramic noz-
zle gently touches the work surface. (fi g.b).
Scratch the tip of the electrode until an arc
develops, quickly withdraw the electrode and
maintaning a gap of approx. 3-4 mm proceed
to weld. To stop welding, simply remove the
torch from the work piece.
REMEMBER to turn OFF the gas immediate-
ly you fi nish welding.
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