Kuhtreiber 150 / TIG LA Bedienungsanweisung Seite 38

Table 4
ELECTRODE (mm)
1.6
2.0
2.5
3.25
4.0
5.0
6.0
Proper values of welding current for the different
diameters of welding electrodes are in 4.
For different types of welding the values are:

High for plane, frontal plane and vertical up-
wards welding.

Medium for overhead welding.

Low for vertical downwards welding and for
joining small pre-heated pieces.
A fairly approximate indication of the average cur-
rent to use in the welding of electrodes for ordinary
steel is given by the following formula:
I=50 x (e-1)
WHERE:
I= intensity of the welding current
e= electrode diameter
EXAMPLE:
For electrode diameter 4 mm
I=50x(4-1)=50x3=150 A
Holding and position of the electrode during welding
Picture 4
o
4 5 + 7 0
Preparation of basic material:
Table 5 shows values for preparation of material. Sizes
are determined according to picture 5.
Picture 5
Table 5
s (mm) a (mm)
0-3 0
3-6 0
3-12 0-1.5
CURRENT (A)
30-60
40-75
60-110
95-140
140-190
190-240
220-330
o
4 5
s
d a
d (mm) α (
0
s/2(max)
0-2 60
Table 6
Diameter of electrode
Tungsten electrode shall be prepared according to the
values in table 7 and picture number 6.
Picture 6
Table 7
Sharpening of tungsten electrode:
By the right choice of tungsten electrode and its pre-
paration we can influence qualities of welding arc,
geometry of the weld and durability/service life of the
electrode. It is necessary to sharpen the electrode
softly in the traverse/horizontal direction according to
picture 7.
Picture 8 shows the influence of sharpening the
electrode on its durability/service life.
o
Picture 7
Picture 8A: soft and well-proportioned sharpening the
electrode in traverse/horizontal direction - durability
up to 17 hours
Picture 8B: rough and irregular sharpening in vertical
direction - durability up to 5 hours
Parameters for comparing the influence of the way of
sharpening the electored are given with the utili-
sation:
HF striking the el. arc, electrodes  3.2 mm welding
current 150 A and welding material pipe.
PROTECTIVE GAS
o )
For welding by method TIG it is necessary to use Argon
0
with the purity 99.99 %. The amount of the flow shall
0
be determined according to the table 8.
-38 -
Welding current
(mm)
1.0
1.6
2.4
α ( o ) Welding current (A)
30
60-90
90-120
A
Picture 8
(A)
15-75
60-150
130-240
0-30
30-120
120-250
B