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MIG/MAG welding method
PRINCIPLE OF MIG/MAG WELDING
Welding wire is lead from the roller into the flow drawing tie with the use of the feed. Arc joins thawing wire
electrode with welding material. Welding wire functions as a carrier of the arc and as the source of additional
material at the same time. Protective gas flows from the spacer who protects arc and the whole weld against the
effects of surrounding atmosphere (pic. 6).
Picture 6
PROTECTIVE GASES
Picture 7
ADJUSTING OF WELDING PARAMETERS
For proximate adjusting of welding current and voltage for MIG/MAG is used formula
U
2
= 14 + 0,05 x I
2
. According
to this formula can be calculated required voltage. When adjusting voltage, we must calculate with its decrease
during welding. Decrease is about 4,8 V / 100 A. Adjusting of welding current - for chosen voltage set required
welding current by increasing or decreasing of wire feeding speed, eventually slightly tune voltage so that welding
arc is stable. For good quality of weld and optimal adjusting of welding current is necessary the range of supply
girder from welded material to be approximately 10x diameter of welding wire (pic. 8).
Picture 8
WELDING ARC TYPES
a/ Short welding arc
Welding with a very short welding arc means low welding arc voltage and current in the low part of the range.
Surface tension of the bath helps to draft in the drop into the melt and consequently new ignition of the welding
arc. This cycle repeats itself every time anew and this way permanent alternation between the short connection
and the welding arc burning period is created. The melt flow is relatively “cool”, so this welding method is suitable
gas opening
tip holder
welding tip
welding arc
wire feeder rolls
welding wire
gas nosle
protection gas
welding
piece
Protective gases
Inert gases
– MIG method
Active gases
– MAG method
Argon (Ar)
Helium (He)
Mixtures He/Ar
CO
₂
Mixed Gates
Ar/CO
₂
Ar/O
₂
