Tig Welding; Quality Of The Weld - Helvi GALILEO 179 Manual De Instrucciones

Avoid hammering the workpiece with the
electrode since it may loose the coating
and increase the arc striking difficulties.
- 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 difficult 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 insufficient 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 flow 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 LIFT 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 flow from the torch nozzle.
FIG.A
- Covering your face with a mask or a hel-
met, bring the tungsten electrode of thetorch
within 3 or 4 mm of the work piece keeping it
at an angle of 45°(fig. b).
- With a rapid movement short - circuit the
tungsten electrode (fig. c) and go back to a
distance of 3-4 mm (fig. d). The arc will be
struck developing a hot and intense light.
EN-7
Gas valve