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EN
Table 3
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 pic. 5.
Pic. 6 shows the effect of grinding the electrode on its
service life.
Pic. 5
Pic. 6
Picture 6A -
Fine and even grinding of the electrode in
the longitudinal direction - Lifetime up to 17 hours
Picture 6B -
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.
Protective gas:
For TIG welding, it is necessary to use argon with a puri
-
ty of 99.99 %. Determine the amount of flow according
to table 4.
Table 4
Welding
current
(A)
Diameter of
electrode
(mm)
Welding nozzle
Flow of
gas
(l/min)
n (°)
Ø (mm)
6 - 70
1.0
4/5
6/8.0
5 - 6
60 - 140
1.6
4/5/6
6.5/8.0/9.5
6 - 7
120 - 240
2.4
6/7
9.5/11.0
7 - 8
Holding the welding torch during welding:
90°
45°
Position W (PA)
Position H (PB)
A B
10 – 30°
15 – 40°
Position H (PB)
10
- 30°
20 - 30°
Position S (PF)
Preparation of basic material:
Table 5 lists the material preparation values.
Dimensions are determined according to pic. 7.
Pic. 7
a
s
α
d
Table 5
s (mm)
a (mm)
d (mm)
α (°)
0 - 3
0
0
0
3
0
0.5 (max)
0
4 - 6
1 - 1.5
1 - 2
60
Basic rules during welding by TIG method:
1. Purity - grease, oil and other impurities must be
removed from the weld during welding. It is also
necessary to mind purity of additional material and
clean gloves of the welder during welding.
2. Leading additional material - oxidation must be
prevented. To do so, flashing end of additional ma-
terial must be always under the protection of gas
flowing from the hose.
3. Type and diameter of tungsten electrodes - it is
necessary to choose them according to the values
of the current, polarity, type of basic material and
composition of protective gas.
4. Sharpening of tungsten electrodes - sharpening the
tip of the electrode should be done in trav-erse/
horizontal direction. The tinier the roughness of
the surface of the tip is, the calmer the burning of
the el. arc is as well as the greater durability of the
electrode is.
