When using Gas Tungsten Arc Welding (GTAW), also known as Tungsten Inert Gas (TIG) welding, for aluminum with alternating current (AC), the tip of the tungsten electrode should be rounded at the tip.
Here's why:
1. AC Welding and Aluminum: Aluminum is typically welded with AC to take advantage of the cleaning action provided by the positive half of the AC cycle, which helps remove the oxide layer on the aluminum surface.
2. Current Effects on the Tungsten: During AC welding, the electrode alternates between positive and negative polarities. The positive polarity tends to ball the tip of the electrode, creating a rounded shape.
3. Optimal Shape for AC Welding: A rounded electrode tip provides a stable arc and helps in the distribution of the heat more evenly across the weld. This reduces the risk of contamination and provides a cleaner, more controlled weld.
Therefore, for welding aluminum with AC using GTAW, the tungsten electrode should be rounded at the tip.
