Strata ADVANCEMULTI205P Operating Instructions Manual page 18

ADVANCEMULTI205P
Gas selection - The purpose of the gas in the
MIG process is to protect / shield the wire,
the arc and the molten weld metal from the
atmosphere. Most metals when heated to a
molten state will re act wit h the air in the
atmosphere, wit hout the protection of the
shielding gas the weld produced would contain
defects li ke porosity, lack of fusion and slag
inclusions. Addit ionall y some of the gas
becomes ionised (electrica ll y charged) and
helps the current flow smoothly.
The correct gas flow is also very important in
protecting the welding zone from the
atmosphere.
Too low flow will give inadequate coverage
and result in weld defects and unstable arc
conditions. Too high flow can cause air to be
drawn into the gas column and contaminate
the weld zone. Use the correct shielding
gas. CO2 is good for steel and offers good
penetration characteristics, the weld profile
is narrower and slightly more raised than the
weld profile obtained from Argon Co2
mixed gas. Argon CO2 mix gas offers better
weld ability for thin metals and has a wider
range of setting tolerance on the machine.
Argon 80% CO2 20% is a good all round
mix suitable for most applications.
Argon Co2
Penetration Pattern for Steel
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C O2
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