voestalpine bohler welding URANOS NX 2200 PMC Manual De Instrucciones página 101

Methods
In MIG welding, two main metal transfer mechanisms are present and they can be classified according to the means by which
metal is transferred from the electrode to the workpiece.
The first process, called "SHORT-ARC", starts with the electrode in direct contact with the weld pool, producing a short circuit
that melts the wire. The short circuit is then broken, re-igniting the arc and repeating the cycle.
I (A)
V (V)
A
B
Welding parameters
The visibility of the arc reduces the need for the user to strictly observe the adjustment tables as he can directly monitor the weld
pool.
• Voltage directly affects the appearance of the weld bead, but its dimensions can be varied to suit requirements by manually
moving the torch to vary the size of the bead at a constant voltage.
• The wire feeding speed is proportional to the welding current.
The two figures show the relationships between the various welding parameters.
V (V)
Diagram for selection the of best working
characteristic.
SHORT cycle and SPRAY ARC welding
Another mechanism for metal transfer is called the "SPRAY-ARC"
method, where the metal transfer occurs in the form of very small
t (ms)
drops that are formed and detached from the tip of the wire and
transferred to the weld pool through the arc stream (Fig. 2b).
t (ms)
I (A)
I (A)
Relationship between wire feeding speed and current
amperage (melting characteristic) according to wire
diameter.
97
OPERATING INSTRUCTIONS
(m/min)
EN