Which statement best describes DCEN in GTAW?

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.

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.