Methods; Welding Parameters - Inteco HARRIER 280 Instrucciones De Uso

6.1.1 Methods

In MIG welding, two mains metal transfer mechanism are
present and they can be classified basing on the means by
which metal is transferred from the electrode to the workpiece.
The first one, defined "SHORT-ARC", produces a small, fast-
freezing weld pool where metal is transferred from the electrode
to the workpiece only during a period when the electrode is
in contact with the weld pool. In this timeframe, the electrode
comes into direct contact with the weld pool generating a short
circuit that melts the wire which is therefore interrupted. The
arc then turn on again and the cycle is repeated (Fig. 1a).
Fig. 1a
Fig. 1b
SHORT cycle (a) and SPRAY ARC welding (b)
Another mechanism for metal transfer is called "SPRAY-ARC"
method, where the metal transfer occurs in the form of very
small drops that are formed and detached form the tip of the
wire and transferred to the weld pool through the arc stream
(Fig. 1b).

6.1.2 Welding parameters

The visibility of the arc reduces the need for the user to strictly
observe the adjustment tables as he can directly control the
weld pool.
- The voltage directly affects the appearance of the bead, but
the dimensions of the weld bead can be varied according to
requirements by manually moving the torch to obtain variable
deposits with constant voltage.
- The wire feeding speed is proportional to the welding cur-
rent.
Fig.2 and 3 show the relations existing between the various
welding parameters.
Fig.2 Diagram for selection of best working characteristic.
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Fig.3 Relation between wire feeding speed and current amper-
age (melting characteristic) according to wire diameter.