Nebraska GTAW FFA TIG Welding Practice Exam

AC frequency in TIG welding aluminum mostly determines how fast the current reverses between the negative and positive legs, which in turn influences arc stability and how the arc cleans the oxide on aluminum. About 60 cycles per second is the standard setting in many North American shop machines, so it’s the most commonly used frequency. This frequency provides a reliable balance between arc wander and control, helping to maintain a stable arc while still allowing the cleaning action needed to break through the aluminum oxide layer. While European setups might use 50 Hz and some users opt for higher frequencies like 120 Hz to tighten the arc on thin material, the everyday, widely taught setting in typical TIG practice is 60 Hz.