Fronius MTG 250i Instructions De Service page 46

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46
Incorrect welding parameters
Correct settings
Poor grounding (earthing) connection
Ensure good contact to workpiece
Inadequate or no protective gas shield
Check the pressure regulator, gas hose, gas solenoid valve and welding
torch shielding gas connection. On gas-cooled welding torches, inspect the
gas seals, use a suitable inner liner
Welding torch is leaking
Replace welding torch
Contact tip is too large or worn out
Replace the contact tip
Wrong wire alloy or wrong wire diameter
Check wirespool/basket-type spool in use
Wrong wire alloy or wrong wire diameter
Check weldability of the base material
The shielding gas is not suitable for this wire alloy
Use the correct shielding gas
Unfavourable welding conditions: shielding gas is contaminated (by mois-
ture, air), inadequate gas shield (weld pool "boiling", draughts), contami-
nants in the workpiece (rust, paint, grease)
Optimise the welding conditions
Welding spatter in the gas nozzle
Remove welding spatter
Turbulence caused by too high a rate of shielding gas flow
Reduce shielding gas flow rate, recommended:
shielding gas flow rate (l/min) = wire diameter (mm) x 10
(e.g. 16 l/min for 1.6 mm wire electrode)
Too large a distance between the welding torch and the workpiece
Reduce the distance between the welding torch and the workpiece (approx.
10 - 15 mm / 0.39 - 0.59 in.)
Tilt angle of the welding torch is too great
Reduce the tilt angle of the welding torch
Wirefeed components do not match the diameter of the wire electrode / the
wire electrode material
Use the correct wirefeed components