PRO-POINT 9085986 Mode D'emploi page 25

V1.0 AC/DC Inverter TIG/Arc Welder 9085986
MATERIAL AND JOINT PREPARATION
The material to be welded should be clean and free of any moisture, paint,
oil, grease, mill scale, rust or any other material that will hinder the arc and
contaminate the weld material. Joint preparation will depend on the method
used include sawing, punching, shearing, machining, flame cutting and
others. In all cases edges should be clean and free of any contaminates. The
type of joint will be determined by the chosen application.
DC TIG (TUNGSTEN INERT GAS) 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 pole (terminal) to the positive pole (terminal).
In the DC electrical circuit there is an electrical
principle at work which should always be taken into
account when using any DC circuit. With a DC circuit
70% of the energy (heat) is always on the positive side
(Fig. 9). This needs to be understood because it
Fig. 9
determines what terminal the TIG torch will be
connected to (this rule applies to all the other
forms of DC welding as well).
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 (Fig. 10).
Fig. 10
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 flowing between the tungsten and the workpiece is the TIG arc and
can be as hot as 34,232 °F. 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.
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