38 | EN
6. Re-approach - Welding current decreases after the set
time to the end value set current (eg 10 A) - filling the
crater.
7. End of the welding process. The digital control auto-
matically switches off the welding process.
Switch off the gas with a valve on the welding torch.
Welding inverters allow TIG welding with touch-trigge-
ring. The TIG method is very effective for welding stain-
less steel. Switch the machine to TIG mode.
Connecting the welding torch and the cable:
Connect the welding torch to the minus pole and the
ground wire to the plus pole - direct polarity.
Selection and preparation of tungsten electrodes:
Table 1 shows the welding current and diameter va-
lues for tungsten electrodes with 2% thoria - red
electrode markings.
Table 1
Diameter of the
Electrode (mm)
Welding Current
(A)
1.0
15 - 75
1.6
60 - 150
2.4
130 - 240
Prepare the Tungsten Electrode according to the va-
lues in Table 2 and Figure 3.
Picture 3
α
Table 2
α (°)
Welding current (A)
30
0 - 30
60 - 90
30 - 120
90 - 120
120 - 250
Grinding of tungsten electrodes:
By proper choice of the tungsten electrode and its
preparation will affect the properties of the welding
arc, weld geometry and electrode life. The electrode
must be gently grinded in the longitudinal direction as
shown in Figure 4. Figure 5 shows the effect of grinding
the electrode on its service life.
Picture 4
Picture 5
Figure 5A -
Fine and even grinding of the electrode in
the longitudinal direction - Lifetime up to 17 hours
Figure 5B -
Coarse and uneven grinding in the transverse
direction - Lifetime 5 hours
Parameters to compare the influence of the electrode
grinding method are given using:
HF ignition el. arc, electrodes Ø 3.2 mm, welding
current 150 A and welded materiál - pipe.
A B
1
2
3
4
5
6
7
1-3 mm
1-3 mm
1-3 mm
8-10 mm
0 - 5 s
POST GAS
I
0
ON
IW
I
START
I
END
Picture 2 - welding process at TIG LA
