Which statement best describes DCEN in GTAW?

• A. With DCEN, a pointed tip concentrates the arc
• B. With DCEN, arc starting with a high-voltage electrical discharge is more difficult
• C. With DCEN, the electrode becomes damaged in a short period of time
• D. DCEN concentrates the heat in the tip of the electrode

Answer: (A)

In GTAW, DCEN means the tungsten electrode is negative and the workpiece is positive. Because the electrode is negative, electrons flow from the tip into the workpiece, producing a high current density at the electrode tip. That high current density concentrates the arc at a small area, so a pointed tungsten tip helps focus the arc for better control and a tighter, more precise weld bead. The other statements don’t reflect how a DCEN arc behaves; arc initiation characteristics, electrode wear, and heat distribution aren’t described in those ways, whereas a pointed tip under DCEN effectively concentrates the arc.