CIGWELD TRANSTIG 300 AC/DC, Service Manual, Page: 40 / 134

TRANSTIG 300 AC/DC SERVICE MANUAL
7-2 June 30, 2008
7.02 Electrode Polarity
Connect the TIG torch to the - / TORCH terminal and the work lead to the + / WORK terminal for direct current
straight polarity. Direct current straight polarity is the most widely used polarity for DC TIG welding. It allows
limited wear of the electrode since 70% of the heat is concentrated at the work piece.
7.03 Tungsten Electrode Current Ranges
Electrode Diameter AC Current (Amps) DC Current (Amps)
0.040” (1.0mm) 30 – 70 30 – 60
1/16” (1.6mm) 60 – 95 60 – 115
3/32” (2.4mm) 125 – 150 100 – 165
1/8” (3.2mm) 130 – 225 135 – 200
5/32” (4.0mm) 190 – 280 190 – 280
3/16” (4.8mm) 250 – 340 250 – 340
Table 7-2: Current ranges for various tungsten electrode sizes
7.04 Tungsten Electrode Types
Electrode Type
(Ground Finish)
Welding Application Features Color
Code
Thoriated 2%
DC welding of mild steel,
stainless steel and copper Excellent arc starting, long life,
high current carrying capacity
Red
Zirconated 1%
High quality AC welding of
aluminium, magnesium and
their alloys Self cleaning, long life,
maintains balled end, high
current carrying capacity
White
Ceriated 2%
AC & DC welding of mild
steel, stainless steel, copper,
aluminium, magnesium and
their alloys Longer life, more stable arc,
easier starting, wider current
range, narrower more
concentrated arc
Grey
Table 7-3: Tungsten Electrode Types