voestalpine Bohler Welding URANOS NX 2700 TLH Mode D'emploi page 38

OPERATING INSTRUCTIONS
Characteristics of TIG welds
The TIG procedure is very effective for welding both carbon and alloyed steel, for first runs on pipes and for welding where good
EN
appearance is important.
Straight polarity is required (D.C.S.P.).
Preparing the edges
Careful cleaning and preparation of the edges are required.
Choosing and preparing the electrode
You are advised to use thorium tungsten electrodes (2% thorium-red coloured) or alternatively cerium or lanthanum electrodes
with the following diameters:
(DC-)
3-20 A
15-80 A
70-150 A
150-250 A
250-400 A
400-500 A
500-750 A
750-1100 A
The electrode must be sharpened as shown in the figure.
Filler metal
The filler rods must have mechanical characteristics comparable to those of the parent metal.
Do not use strips obtained from the parent metal, since they may contain working impurities that can negatively affect the
quality of the welds.
Shielding gas
Typically, pure argon (99.99%) is used.
(DC-)
3-20 A
15-80 A
70-150 A
150-250 A
250-400 A
400-500 A
500-750 A
750-1100 A
Current range
(DC+)
-
-
10-20 A
15-30 A
25-40 A
40-55 A
55-80 A
80-125 A
Current range
(DC+)
-
-
10-20 A
15-30 A
25-40 A 100-180 A
40-55 A 160-240 A
55-80 A 190-300 A
80-125 A 325-450 A
(AC)
3-20 A 0,5 mm
20-30 A 1,0 mm
30-80 A 1,6 mm
60-130 A 2,4 mm
100-180 A 3,2 mm
160-240 A 4,0 mm
190-300 A 4,8 mm
325-450 A 6,4 mm
(AC) Nozzle
3-20 A n° 4
20-30 A n° 5
30-80 A n° 6
60-130 A n° 7
n° 8
n° 8
n° 10
n° 12
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Electrode
Ø
30°
30-60°
60-90°
90-120°
120-150°
150-180°
150-180°
150-180°
Gas
Flow
5-6 l/min
6-8 l/min
7-10 l/min
8-12 l/min
10-14 l/min
12-16 l/min
15-20 l/min
20-25 l/min