SECTION 8 − SELECTING AND PREPARING A TUNGSTEN FOR DC OR AC WELDING WITH INVERTER MACHINES
gtaw_Inverter_7/2006
Y Whenever possible and practical, use DC weld output instead of AC weld output.
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| Amperage Range - Gas Type♦ - Polarity | ||
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Electrode Diameter |
| (DCEN) − Argon |
| AC − Argon |
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| Direct Current Electrode Negative |
| Balance Control @ 65% Electrode Negative |
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| (For Use With Mild Or Stainless Steel) |
| (For Use With Aluminum) |
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2% Ceria (Orange Band), 1.5% Lanthanum (Gray Band), Or 2% Thorium (Red Band) Alloy Tungstens | ||||
.010” (1 mm) |
| Up to 25 |
| Up to 20 |
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.020” (1 mm) |
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.040” (1 mm) |
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1/16” (1.6 mm) |
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3/32” (2.4 mm) |
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1/8” (3.2 mm) |
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5/32” (4.0 mm) |
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3/16” (4.8 mm) |
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1/4” (6.4 mm) |
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♦Typical argon shielding gas flow rates are 11 to 35 cfh (cubic feet per hour).
Figures listed are a guide and are a composite of recommendations from American Welding Society (AWS) and electrode manufacturers.
Y Grinding the tungsten electrode produces dust and flying sparks which can cause injury and start fires. Use local exhaust (forced ventilation) at the grinder or wear an approved respirator. Read MSDS for safety infor- mation. Consider using tungsten containing ceria, lanthana, or yttria instead of thoria. Grinding dust from thoriated electrodes contains
Radial Grinding
Causes Wandering Arc
Wrong Tungsten Preparation
Electrode Diameter
2 | 3 |
1
4
Ideal Tungsten Preparation − Stable Arc
1 Grinding Wheel
Grind end of tungsten on fine grit, hard abrasive wheel before welding. Do not use wheel for other jobs or tungsten can become contaminated causing lower weld quality.
2 Tungsten Electrode
A 2% ceriated tungsten is recommended.
3 Flat
Diameter of this flat determines amperage capacity.
4 Straight Ground
Grind lengthwise, not radial.
