Tig Ac Welding - Kemppi MasterTig ACDC 3500W Operating Manual

2.8 TIG AC welding

AC-current is typically used when welding aluminium. We recommend for AC-welding a
WC20 (grey) or a clean wolfram electrode (green).
2.8.1 Balance
In AC-welding the ratio between the positive and negative half-cycle is called balance.
With the balance you can control heat between the electrode and work piece. When
balance is positive, it means that the positive half-cycle is longer than the negative, more
heat is coming to the electrode than to the work piece. Correspondingly when balance
is negative, negative half-cycles are longer, the work piece is hotter and the electrode is
colder. Mastertig AC/DC-machines have build-in BALANCE-automatism, which chooses
automatically right balance value. User adjusts the BALANCE-knob according to the
electrode, and the machine takes care of the balance control in different currents.
© Kemppi Oy 2021
BALANCE automatics offers two benefits as compared to a constant balance:
• In AC welding, you can use both a sharpened and a rounded (cut) electrode.
When welding starts, the machine will round the cut tip so that its is suitable.
• The current-range of the electrode is extended: the current of the lower end is
lowered and the current of the maximum end is increased.
With BALANCE automatics, you can use the position for a sharpened
electrode with a narrower arc to obtain a narrower seam and to a deeper
penetration than with a rounded electrode. A narrow seam is useful
especially in fillet welding.
When using a rounded electrode, the arc is broad and the cleaning area
of the arc is also wider, so it can be used for end-to-end seams and outer
corners.
The table is only given as a guide.
Welding current range Electrode
min. min. max.
WC20
A A A ø mm
15 25 90 1,6
20 30 150 2,4
30 45 200 3,2
40 60 350 4,0
The table and the panel scale are based on the use of WC20 (grey). When using pure
wolfram electrode (green) the tip rounds off slightly.
8
MasterTig ACDC 3500W
Gas nozzle Gas flow rate
Argon
number l / min
ø mm
4/5/6 6,5/8,0/9,5 l / min6...7
6/7 9,5/11,0 7...8
7/8/10 11,0/12,5/16 8...10
10/11 16/17,5 10...12
R01