MetFab - Air Products Welder's Handbook - Flipbook - Page 20
The diameter of the electrode is chosen
to match the current. The maximum
current which a given diameter of
electrode can carry is determined as
the current beyond which the electrode
overheats and melts. The minimum
current depends on arc stability.
Electrode diameter
(mm)
Direct current
(A)
Zirconated and
Pure Tungsten
Ceriated, Thoriated
and Lanthanated
1.0
15 - 80
10 - 30
20 - 60
1.6
50 - 150
30 - 80
50 - 120
2.4
100 - 250
60 - 130
80 - 180
3.2
200 - 400
100 - 180
160 - 250
Before use, the end of the electrode
is prepared using a special electrode
grinder to give the most appropriate
profile.
For DC welding a sharp point is
required. For AC welding only a small
bevel is needed as the end of the
electrode becomes rounded when the
arc is operated.
AC welding
Ø All mm
Top Tip
When grinding tungsten electrodes
it is recommended that a dedicated
grindstone with local dust extraction
is used and a filter mask and eye
protection is worn.
16
DC welding
Ø≥3.2mm
AC square
wave welding
Ø All mm
DC welding
Ø
