Firepower MST 220i, Operating Manual

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FIREPOWER MST 220i
BASIC WELDING 4-18 Manual 0-5343
4.06 TIG (GTAW) Basic Welding Technique
Gas Tungsten Arc Welding (GTAW) or TIG (Tungsten Inert Gas) as it is commonly referred to, is a welding process
in which fusion is produced by an electric arc that is established between a single tungsten (non-consumable)
electrode and the work piece. Shielding is obtained from a welding grade shielding gas or welding grade shielding
gas mixture which is generally Argon based. A filler metal may also be added manually in some circumstances
depending on the welding application.
Welds Made With or Without
Addition of Filler Metal
Work Piece
Can Be Any Commercial
Metal
Gas Cup
Either Ceramic,
High-lmpact or
Water Cooled
Metal
Inert Gas
Shields Electrode
and Weld Puddle
Tungsten Electrode
Non-Consumable
Art # A-09658_AC
Figure 4-40: TIG (GTAW) Welding Application Shot
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” (5mm) 250-340
Table 4-6: Current Ranges for Various Tungsten Electrode Sizes
Guide for Selecting Filler Wire Diameter
Filler Wire Diameter DC Current Range (Amps)
1/16” (1.6mm) 20-90
3/32” (2.4mm) 65-115
1/8” (3.2mm) 100-165
3/16” (5mm) 200-350
Table 4-7: Filler Wire Selection Guide