OPERATION
DC TIG welding is a process in which an arc is struck
between a TUNGSTEN electrode and the metal work
piece. The weld area is shielded by an inert gas flow to
prevent contamination of the tungsten, molten pool and
weld area. When the TIG arc is struck the inert gas is
ionized and superheated changing it’s molecular
structure which converts it into a plasma stream. This plasma stream flowing between the
tungsten and the work piece is the TIG arc and can be as hot as 19,000°C. It is a very pure
and concentrated arc which provides the controlled melting of most metals into a weld pool.
TIG welding offers the user the greatest amount of flexibility to weld the widest range of
material and thickness and types. DC TIG welding is also the cleanest weld with no sparks
or spatter.
The intensity of the arc is proportional to the
current that flows from the tungsten. The
welder regulates the welding current to
adjust the power of the arc. Typically thin
material requires a less powerful arc with
less heat to melt the material so less current
(amps) is required, thicker material requires a more powerful arc with more heat so more
current (amps) are necessary to melt the material.
LIFT ARC IGNITION for TIG (tungsten inert gas) Welding
Lift Arc is a form of arc ignition where the machines has low voltage on the electrode to only
a few volts, with a current limit of one or two amps (well below the limit that causes metal to
transfer and contamination of the weld or electrode). When the machine detects that the
tungsten has left the surface and a spark is present, it immediately (within microseconds)
increases power, converting the spark to a full arc. It is a simple, safe lower cost alternative
arc ignition process to HF (high frequency) and a superior arc start process to scratch start.
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