In DCEN operation, which of the following is true about arc behavior?

In DCEN operation, which of the following is true about arc behavior?

• A. A pointed tip concentrates the arc
• B. Arc starting with a high-voltage discharge is easy
• C. The electrode remains unharmed
• D. Heat is concentrated away from the tip

Answer: (A)

In DCEN, the shape of the tungsten tip strongly controls where the arc attaches. A sharp, pointed tip creates a high local electric field, which anchors the arc right at the tip and makes the arc more concentrated and focused. That sharper arc gives you better control and more precise penetration for a given current. If the tip is dull or rounded, the arc spreads out, making control and weld shape less predictable. The other ideas don’t fit what actually happens: starting the arc with a high-voltage discharge isn’t inherently easy or reliable in GTAW and depends on the power source’s starting method; the electrode will experience erosion and isn’t guaranteed to stay unharmed under welding heat; and heat isn’t concentrated away from the tip—the arc delivers heat into the weld zone near the workpiece, with the arc being held at the tip.

In DCEN, the shape of the tungsten tip strongly controls where the arc attaches. A sharp, pointed tip creates a high local electric field, which anchors the arc right at the tip and makes the arc more concentrated and focused. That sharper arc gives you better control and more precise penetration for a given current. If the tip is dull or rounded, the arc spreads out, making control and weld shape less predictable.

The other ideas don’t fit what actually happens: starting the arc with a high-voltage discharge isn’t inherently easy or reliable in GTAW and depends on the power source’s starting method; the electrode will experience erosion and isn’t guaranteed to stay unharmed under welding heat; and heat isn’t concentrated away from the tip—the arc delivers heat into the weld zone near the workpiece, with the arc being held at the tip.