3.1 Applications
3.1.1 TIG welding
TIG welding with alternating or direct current. Arc ignition optionally by means of non-contact HF ignition
or contact ignition with Liftarc.
3.1.1.1 TIG hot wire welding
The TIG hot wire welding system technology is based on the TIG cold wire welding system technology.
A wire feed system transports the wire-like welding consumable, which is heated at the stick-out between
contact tip and weld pool contact point by means of resistance heating. A second power source is
required for this resistance heating. Its secondary power circuit is closed by the wire's permanent contact
with the weld pool. The process of pre-heating the wire can be controlled in a wide range by the selected
hot wire power.
By pre-heating the wire, the energy taken from the weld pool for melting the wire can be reduced. This
allows a significantly larger amount of welding consumables to be used at a higher welding speed, thus
reducing the energy per unit length.
3.1.1.2 TIG cold wire welding
Cold wire welding is a variant of TIG welding featuring mechanically fed filler material. With this process,
cold welding wire is melted, without power, in the arc of a tungsten electrode.
3.1.1.3 TIG activArc welding
The EWM activArc process, thanks to the highly dynamic controller system, ensures that the power
supplied is kept virtually constant in the event of changes in the distance between the welding torch and
the weld pool, e.g. during manual welding. Voltage losses as a result of a shortening of the distance
between the torch and molten pool are compensated by a current rise (ampere per volt - A/V), and vice
versa. This helps prevents the tungsten electrode sticking in the molten pool and the tungsten inclusions
are reduced. This is particularly useful in tacking and in spot welding.
3.1.1.4 spotArc
This process is suitable for tack welding or joint welding of metal sheets made from steel and CrNi alloys
up to a thickness of approximately 2.5 mm. Metal sheets of different thicknesses can also be welded on
top of one another. As this is a one-sided process, it is also possible to weld metal sheets onto tubular
sections such as round or square pipes. In arc spot welding, the arc melts through the upper metal sheet
and the lower metal sheet is melted onto it. This produces flat, fine-textured welding tacks which require
little or no post weld work, even in visible areas.
3.1.1.5 Spotmatic
In contrast to the operating mode spotArc, the arc ignites not by pressing the torch trigger as is usual, but
by shortly touching the tungsten electrode against the workpiece. The torch trigger is used for process
activation.
3.1.2 MMA welding
Manual arc welding or, for short, MMA welding. It is characterised by the fact that the arc burns between
a melting electrode and the molten pool. There is no external protection; any protection against the
atmosphere comes from the electrode.
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