Tweco 300 DC Arcmaster - Manual (Page 44)

ARCMASTER 300 ACDC
7-2 Februrary 22, 2006
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%
Zirconated 1%
Ceriated 2%
DC welding of mild steel,
stainless steel and copper.
High quality AC welding of
aluminium, magnesium and
their alloys.
Red
White
Grey
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.
Excellent arc starting, Long life,
High current carrying capacity.
Self cleaning, Long life,
Maintains balled end, High
current carrying capacity.
Table 7-3: Tungsten electrode types