voestalpine Bohler Welding URANOS NX 2200 SMC Classic Mode D'emploi page 44

OPERATING INSTRUCTIONS
Gases
MIG-MAG welding is defined mainly by the type of gas used: inert for MIG welding (Metal Inert Gas), active for MAG welding
EN
(Metal Active Gas).
- Carbon dioxide (CO )
Using CO as shielding gas gives high penetration and a high feed speed, resulting in good mechanical properties and low
operating costs. On the other hand, CO causes considerable problems with the final chemical composition of the joints as it
removes easily oxidisable elements and simultaneously enriches the carbon content of the weld pool.
Welding with pure CO
porosity.
- Argon
This inert gas is used in pure form to weld light alloys but is best mixed with oxygen and CO in a percentage of 2% to weld
chrome-nickel stainless steels, as this contributes to the stability of the arc and improves the form of the bead.
- Helium
This gas is used as an alternative to argon and permits greater penetration (on thick material) and faster wire feeding.
- Argon-Helium mixture
Provides a more stable arc than pure helium, and greater penetration and travel speed than argon.
- Argon-CO and Argon-CO -Oxygen mixture
These mixtures are used in the welding of ferrous materials especially in SHORT-ARC operating mode as they improve the
specific heat contribution.
They can also be used in SPRAY-ARC.
Normally the mixture contains a percentage of CO ranging from 8% to 20% and O around 5%.
Consult the instruction manual of the system.
Unalloyed steel / High alloyed steel
Current range
3-50 A
30-100 A
75-150 A
150-250 A
250-400 A
400-500 A
Gas flow
10-12 l/min
10-14 l/min
12-16 l/min
14-18 l/min
16-20 l/min
18-22 l/min
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Aluminum alloy
Current range
3-50 A
30-100 A
75-150 A
150-250 A
250-400 A
400-500 A
Gas flow
10-12 l/min
10-15 l/min
12-18 l/min
14-22 l/min
16-25 l/min
18-30 l/min