GTAW (TIG) Welding & Special Materials
GTAW current types for aluminum, shielding gas flow rates, tungsten electrode selection, helium vs argon, stainless steel and galvanized steel welding, manganese and hexavalent chromium OELs.
- Select the correct current type for GTAW welding of aluminum
- Identify typical shielding gas flow rates for GTAW
- Choose appropriate tungsten electrode types for steel and aluminum
- Compare helium and argon shielding gas properties
- Describe precautions for welding stainless and galvanized steel
- State 2025/2026 ACGIH TLVs for manganese and hexavalent chromium and required controls
Leçon 1
GTAW Fundamentals & Current Selection
Current for Aluminum
The type of current typically used for GTAW (TIG) welding of aluminum is AC with high frequency. Alternating current provides the unique combination needed for aluminum - the DCEP half-cycle provides oxide cleaning action on the aluminum surface, while the DCEN half-cycle provides the majority of heat and penetration. High frequency stabilizes the arc during zero-crossing points.
GTAW Process Advantages
The welding process that produces the cleanest welds with minimal post-weld cleaning required is GTAW. Because GTAW uses a non-consumable tungsten electrode and a separate filler rod with inert gas shielding, there is no flux to create slag and virtually no spatter. This makes GTAW ideal for critical applications where weld cleanliness is paramount.
Exam Tip
GTAW produces the cleanest welds of any common arc welding process. When the exam asks about minimum post-weld cleaning, GTAW is always the answer - not SMAW, FCAW, or SAW.
Use AC with high frequency for GTAW welding of aluminum. GTAW produces the cleanest welds with minimal post-weld cleaning required.