Which is a true characteristic of DCEP with GTAW?

• A. There is oxide cleaning action
• B. There is no oxide cleaning action
• C. Heat balance is 50/50
• D. The arc is always stable

Answer: (A)

In GTAW, polarity changes where most of the arc energy goes and how the surface interacts with the arc. Using direct current with the electrode as the positive pole causes the arc to act on the workpiece in a way that breaks up and washes away surface oxides. That cleaning action exposes cleaner base metal at the weld zone, which helps with fusion and results in a better weld bead, especially on metals with tough oxide films.

The other statements don’t hold as general truths. The idea of a fixed 50/50 heat balance isn’t accurate because heat distribution depends on polarity and welding conditions, and arc stability isn’t guaranteed in all situations — it varies with amperage, shielding gas, joint fit, and material.