Tweco 300 TS Arcmaster(Feb2006) - Manual (Page 39)

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7.0 BASIC TIG WELDING GUIDE
7.01 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.
7.02 Tungsten Electrode Current Ranges
Electrode Diameter DC Current (Amps)
0.040” (1.0mm) 30 – 60
1/16” (1.6mm) 60 – 115
3/32” (2.4mm) 100 – 165
1/8” (3.2mm) 135 – 200
5/32” (4.0mm) 190 – 280
3/16” (4.8mm) 250 – 340
Table 7 – Current Ranges for Various Tungsten Electrode Sizes
7.03 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
Ceriated 2%
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 8 – Tungsten Electrode Types