Maintaining The System; Welding Defects - Elettro CF Pro Mig 277 Manual De Instrucciones

• Unscrew the contact tip.
• Insert the wire in the wire liner of the torch, making sure
that it is inside the roller groove and that the roller is in
the correct position.
• Press the torch trigger to move the wire forward until it
comes out of the torch.
• Caution: keep your face away from the gun tube
assembly while the wire is coming out.
• Screw the contact tip back on, making sure that the hole
diameter is the same as that of the wire used.
• Assemble the gas nozzle.
4.3 WELDING CARBON
PROTECTION.
In order to weld these materials you must:
• Use a welding gas with a binary composition, usually
ARGON + CO2 with percentages of Argon ranging from
75% up. With this blend, the welding bead will be well
jointed and attractive.
• Using pure CO2 as a protection gas will produce narrow
beads, with greater penetration but a considerably
increase in splatters.
• Use a welding wire of the same quality as the steel to be
welded. It is best to always use good quality wires,
avoiding welding with rusted wires that could cause

welding defects.

• Avoid welding rusted parts, or those with oil or grease
stains.
4.4 WELDING STAINLESS STEEL
Series 300 stainless steels must be welded using a
protection gas with a high Argon content, containing a
small percentage of O2 or carbon dioxide CO2
(approximately 2%) to stabilize the arc.
Do not touch the wire with your hands. It is important to
keep the welding area clean at all times, to avoid
contaminating the joint to be welded.
4.5 WELDING ALUMINIUM
In order to weld aluminium you must use:
• Pure Argon as the protection gas.
• A welding wire with a composition suitable for the base
material to be welded.
• Use mills and brushing machines specifically designed
for aluminium, and never use them for other materials.
5 WELDING DEFECTS
1. DEFECT- - Porosity (within or outside the bead)
CAUSES - Electrode defective (rusted surface)
- Missing shielding gas due to:
low gas flow
flow gauge defective
regulator frosted due to no preheating of the
CO2 protection gas
defective solenoid valve
contact tip clogged with spatter
gas outlet holes clogged
air drafts in welding area.
2. DEFECT - Shrinkage cracks
CAUSES - Wire or workpiece dirty or rusted.
- Bead too small.
STEELS WITH GAS
- Bead too concave.
- Bead too deeply penetrated.
3. DEFECT - Side cuts
CAUSES - Welding pass done too quickly
- Low current and high arc voltages.
4. DEFECT - Excessive spraying
CAUSES - Voltage too high.
- Insufficient inductance.
- No preheating of the CO2 protection gas

6 MAINTAINING THE SYSTEM

• Shielding gas nozzle
This nozzle must be periodically cleaned to remove weld
spatter. Replace if distorted or squashed.
• Contact tip.
Only a good contact between this contact tip and the wire
can ensure a stable arc and optimum current output; you
must therefore observe the following precautions:
A) The contact tip hole must be kept free of grime and
oxidation (rust).
B) Weld spatter sticks more easily after long welding
sessions, blocking the wire flow.
The tip must therefore be cleaned more often, and
replaced if necessary.
C) The contact tip must always be firmly screwed onto the
torch body. The thermal cycles to which the torch is
subjected can cause it to loosen, thus heating the torch
body and tip and causing the wire to advance unevenly.
• Wire liner.
This is an important part that must be checked often,
because the wire may deposit copper dust or tiny
shavings. Clean it periodically along with the gas lines,
using dry compressed air.
The liners are subjected to constant wear and tear, and
therefore must be replaced after a certain amount of time.
• Gearmotor group.
Periodically clean the set of feeder rollers, to remove any
rust or metal residue left by the coils. You must
periodically check the entire wire feeder group: hasp, wire
guide rollers, liner and contact tip.
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