iWeld 800MLTG2400PFC, Руководство пользователя

Страница: 108 / 131

EN
4.2.2 DCTIG Welding
The DC power source uses what is known as DC (direct current) in
which the main electrical component, known as electrons, flow in only
one direction from the negative terminal (-) to the positive terminal (+).
In the DC electrical circuit there is an electrical principle at work which
provides that, in a DC circuit, 70% of the energy (heat) is always on the
positive side. This is important because it determines what terminal to
connect the TIG torch.
DC TIG welding is a process in which an arc is struck between
a tungsten electrode and the metal workpiece. 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 its’
molecular structure which converts it into a plasma stream. This
plasma stream that flows 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 materials, thickness and profiles. 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 Welding
Lift Arc is a form of arc ignition where the machine has 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
24