Elettro 293 Manual De Instrucciones página 11

4.4 WELDING CARBON
PROTECTION.
Make sure that the cables are properly inserted on the
terminal board, so that the poles match correctly (only for
item 291, see pict. 4).
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.
4.5 WELDING STAINLESS STEEL
Make sure that the cables are properly inserted on the
terminal board, so that the poles match correctly (only for
Item 291, see pict. 4).
Series 300 stainless steels must be welded using a
protection gas with a high Argon content, containing a
small percentage of
(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.
4.6 WELDING ALUMINIUM
Make sure that the cables are properly inserted on the
terminal board, so that the poles match correctly (only for
Item 291, see picture 4).
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.
• In order to weld aluminium you must use the torches:
P3KP or SPOOL-GUN with the connection item 530196.
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.
• 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
STEELS WITH
O2 or carbon dioxide
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.
CO2 • 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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