3
Process Variations-Metal Transfer
The basic mig process includes three
distinctive process techniques: short circuiting metal transfer, globular
transfer, and spray arc. These techniques
describe the manner in which metal is transferred from the wire to
the weld pool. In short circuiting metal
transfer, also known as ”Short Arc”, ”Dip Transfer”, and ”Microwire”,
metal transfer occurs when an electrical
short circuit is established. This occurs as the molten metal at the
end of the wire touches the molten weld
pool. In spray arc welding, small molten drops of metal are
detached from the tip of the wire and
projected by electromagnetic forces towards the weld pool. Globular
transfer occurs when the drops of metal
are quite large and move toward the weld pool under the influence
of gravity. Factors that determine the
manner of metal transfer are the welding current, wire size, arc length
(voltage), power supply characteristics,
and shielding gas.
Figure
1-1 – Types of Metal Transfer
