Mig Welding Trouble Shooting - Unimig VIPER Operating Manual

MIG WELDING TROUBLE SHOOTING

The following chart addresses some of the common problems of MIG welding. In all cases of equipment malfunction, the manufacturer's recommendations
should be strictly adhered to and followed.
1: Excessive Spatter
Possible Reason
Wire feed speed set too high
Voltage too high
Wrong polarity set
Stick out too long
Contaminated base metal
Contaminated MIG wire
Inadequate gas flow or too much gas flow
2: Porosity - small cavities or holes resulting from gas pockets in weld metal.
Possible Reason
Wrong gas
Inadequate gas flow or too much gas flow
Moisture on the base metal
Contaminated base metal
Contaminated MIG wire
Gas nozzle clogged with spatter, worn or out
of shape
Missing or damaged gas diffuser
MIG torch Euro connect O-ring missing or
damaged
3: Wire stubbing during welding
Possible Reason
Holding the torch too far away
Welding voltage set too low
Wire Speed set too high
4: Lack of Fusion − failure of weld metal to fuse completely with base metal or a proceeding weld bead.
Possible Reason
Contaminated base metal
Not enough heat input
Improper welding technique
5: Excessive Penetration − weld metal melting through base metal
Possible Reason
Too much heat
6: Lack of Penetration − shallow fusion between weld metal and base metal
Poor in incorrect joint preparation
Not enough heat input
Contaminated base metal
40 | VIPER MIG 185 Manual
Suggested Remedy
Select lower wire feed speed
Select a lower voltage setting
Select the correct polarity for the wire being used - see machine setup guide
Bring the torch closer to the work
Remove materials like paint, grease, oil, and dirt, including mill scale from base metal
Use clean dry rust free wire. Do not lubricate the wire with oil, grease etc
Check the gas is connected, check hoses, gas valve and torch are not restricted. Set the gas flow
between 6-12 l/min flow rate. Check hoses and fittings for holes, leaks etc
Protect the welding zone from wind and drafts
Suggested Remedy
Check that the correct gas is being used
Check the gas is connected, check hoses, gas valve and torch are not restricted. Set the gas flow
between 10 - 15 l/min flow rate. Check hoses and fittings for holes, leaks etc.
Protect the welding zone from wind and drafts
Remove all moisture from base metal before welding
Remove materials like paint, grease, oil, and dirt, including mill scale from base metal
Use clean dry rust free wire. Do not lubricate the wire with oil, grease etc
Clean or replace the gas nozzle
Replace the gas diffuser
Check and replace the O-ring
Suggested Remedy
Bring the torch closer to the work and maintain stick out of 5-10mm
Increase the voltage
Decrease the wire feed speed
Suggested Remedy
Remove materials like paint, grease, oil, and dirt, including mill scale from base metal
Select a higher voltage range and /or adjust the wire speed to suit
Keep the arc at the leading edge of the weld pool.
Gun angle to work should be between 5 & 15°
Direct the arc at the weld joint
Adjust work angle or widen groove to access bottom during welding
Momentarily hold arc on side walls if using weaving technique
Suggested Remedy
Select a lower voltage range and /or adjust the wire speed to suit
Increase travel speed
Material too thick. Joint preparation and design needs to allow access to bottom of groove while
maintaining proper welding wire extension and arc characteristics
Keep the arc at the leading edge of the weld pool and maintain the gun angle at
5 & 15° keeping the stick out between 5-10mm
Select a higher voltage range and /or adjust the wire speed to suit
Reduce travel speed
Remove materials like paint, grease, oil, and dirt, including mill scale from base metal.