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prepare the tungsten electrode according to the va
-
lues in table 2 and picture 2.
picture 2
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 pre
-
paration 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 picture 3. picture 4 shows the effect of grinding the
electrode on its service life.
picture 3
picture 4
Picture 4A -
Fine and even grinding of the electrode in
the longitudinal direction - lifetime up to 17 hours
Picture 4B -
coarse and uneven grinding in the
transverse direction - lifetime about 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 material - 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 3.
table 3
Welding
current
(A)
Ø 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
a b
Holding the welding torch during welding:
90°
45°
position W (pa)
position h (pB)
10 – 30°
15 – 40°
position s (pF)
10
- 30°
20 - 30°
position s (pF)
Preparation of basic material:
table 4 lists the material preparation values.
dimensions are determined according to pic. 5.
picture 5
a
s
α
d
table 4
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
material 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
en
