Normal stick out
Too short
Too long
Even arc, good
penetration even
fusion, good finish.
Unstable arc, spatter,
over heat contact tip.
Unstable
spatter,
penetration
fusion.
arc, poor
and
Travel Speed - Travel speed is the rate that
the gun is moved along the weld joint and is
usually measured in mm per minute. Travel
speeds can vary depending on conditions
and the welders skil l and is limi ted to the
welders ability to control the weld pool. Push
technique allows faster travel speeds than
Drag technique. Gas flow must also
correspond with the travel speed,
increasing with faster travel speed and
decreasing with slower speed. Travel speed
needs to match the amperage and wil l
decrease as the material thickness and
amperage increase.
Too Fast Travel Speed - A too fast
travel speed produces too little heat per
mm of travel resulting in less
penetration and reduced weld fusion, the
weld bead solidifies very quickly
trapping gases inside the weld metal
causing porosity. Undercutting of the
base metal can also occur and an
unfilled groove in the base metal is
created when the travel speed is too fast
to allow molten metal to flow into the
weld crater created by the arc heat.
Too Fast Travel Speed
high narrow bead
undercut
lack of fusion
lack of joint penetration
spatter
porosity
15
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