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The wire approaches the work
piece and touches the work cre-
ating a short circuit between the
wire and the base metal, because
there is no space between the wire
and the base metal there is no arc
and current flows through the wire
.
The wire cannot support all the
current flow, resistance builds
up and the wire becomes hot
and weak and begins to melt
The current flow creates a mag-
netic field that begins to pinch the
melting wire forming it into droplet
short circuit
wire heating
magnetic
field pinches
wire
The pinch causes the forming
droplet to separate and fall to-
wards the now creating weld pool.
An arc is created at the separation
of the droplet and the heat and force
of the arc flattens out the droplet
into the weld pool. The heat of the
arc melts the end of the wire slightly
as it feeds towards the base metal
The wire feed speed overcomes
the heat of the arc and the wire
again approaches the work to
short circuit and repeat the cycle.
droplet
separates
arc flattens
the droplet
cycle
repeats
MIG (Metal Inert Gas) Welding
Short Circuit Transfer - Short circuit transfer is the most common used method whereby the wire
electrode is fed continuously down the welding torch through to and exiting the contact tip. The
wire touches the work piece and causes a short circuit the wire heats up and begins to form a
molten bead, the bead separates from the end of the wire and forms a droplet that is transferred
into the weld pool. This process is repeated about 100 times per second, making the arc appear
constant to the human eye.
