Fronius MTG 250i Manual De Instrucciones página 57

Poor weld properties
Cause: Incorrect welding parameters
Remedy: Correct settings
Cause: Poor grounding (earthing) connection
Remedy: Ensure good contact to workpiece
Cause: Too little or no shielding gas
Remedy: Check the pressure regulator, gas hose, gas solenoid valve and wel-
ding torch shielding gas connection. On gas-cooled welding torches,
inspect the gas seals, use a suitable inner liner
Cause: Welding torch is leaking
Remedy: Replace welding torch
Cause: Contact tip is too large or worn out
Remedy: Replace contact tip
Cause: Wrong wire alloy or wrong wire diameter
Remedy: Check wirespool/basket-type spool in use
Cause: Wrong wire alloy or wrong wire diameter
Remedy: Check weldability of the base material
Cause: The shielding gas is not suitable for this wire alloy
Remedy: Use the correct shielding gas
Cause: Unfavourable welding conditions: shielding gas is contaminated (by
moisture, air), inadequate gas shield (weld pool "boiling", draughts),
contaminants in the workpiece (rust, paint, grease)
Remedy: Optimise the welding conditions
Cause: Shielding gas escaping at clamping nipple
Remedy: Use the correct clamping nipple
Cause: Clamping nipple seal ring defective, shielding gas escaping at clam-
ping nipple
Remedy: Replace clamping nipple to ensure a gas-tight seal
Cause: Welding spatter in the gas nozzle
Remedy: Remove welding spatter
Cause: Turbulence caused by too high a rate of shielding gas flow
Remedy: 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)
Cause: Distance between the welding torch and the workpiece too great
Remedy: Reduce the distance between the welding torch and the workpiece
(approx. 10 - 15 mm / 0.39 - 0.59 in.)
Cause: Tilt angle of the welding torch is too great
Remedy: Reduce the tilt angle of the welding torch
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