Effect of DCEP in TIG welding?

• A. Deep penetration but wide arc
• B. Cleaning action with deep penetration
• C. Cleaning action but shallow penetration
• D. No effect on weld characteristics

Answer: (C)

DCEP in TIG welding means the electrode is positive and the workpiece is negative. This polarity shifts heat toward the electrode, so less heat is delivered into the base metal, which tends to produce shallower penetration. At the same time, the positive polarity enhances the arc’s ability to break up and remove surface oxides, giving a cleaning action on the weld surface. Metals with oxide films—like aluminum—benefit from this cleaning effect, helping achieve a cleaner weld interface. So the combination is a cleaning action with shallow penetration. If you need deeper fusion, you’d use a polarity that sends more heat into the workpiece (such as DCEN), but that reduces the cleaning action.