PRO-POINT 9085986 Mode D'emploi page 30

9085986 AC/DC Inverter TIG/Arc Welder V1.0
held in place until a weld pool is created, a
circular movement of the tungsten will assist is
creating a weld pool of the desired size. Once
the weld pool is established tilt the torch at
about a 75° angle and move smoothly and
evenly along the joint (Fig. 19).
The filler metal is introduced to the leading edge
of the weld pool. The filler wire is usually held at
about a 15° angle and fed into the leading edge
of the molten pool, the arc will melt the filler
wire into the weld pool as the torch is moved
forward. Also a dabbing technique can be used
to control the amount of filler wire added, the
wire is fed into the molten pool and retracted in
a repeating sequence as the torch is moved
slowly and evenly forward (Fig 20). It is
important during the welding to keep the
molten end of the filler wire inside the gas
shield as this protects the end of the wire from
being oxidized and contaminating the weld pool.
Fig. 20
TUNGSTEN ELECTRODES
Tungsten is a rare metallic element used for manufacturing TIG welding
electrodes. The TIG process relies on tungsten's hardness and high-
temperature resistance to carry the welding current to the arc. Tungsten has
the highest melting point of any metal, 6,170 degrees Fahrenheit.
Tungsten electrodes are non-consumable and come in a variety of sizes, they are
made from pure tungsten or an alloy of tungsten and other rare earth elements.
Choosing the correct tungsten depends on the material being welded, the
number of amps required and whether you are using AC or DC welding current.
Tungsten electrodes are colour-coded at the end for easy identification.
THORIATED
Colour Red (2%), Yellow (1%), DC Welding Only
Thoriated tungsten electrodes (AWS classification EWTh-2) contain a
minimum of 97.30 percent tungsten and 1.70 to 2.20 percent thorium and
are called 2 percent thoriated. They are the most commonly used electrodes
today and are preferred for their longevity and ease of use. Thorium increases
the electron emission qualities of the electrode, which improves arc starts
30 For technical questions call 1-800-665-8685