Using direct current electrode positive (DCEP) in GMAW tends to produce cleaning action.

Using direct current electrode positive (DCEP) in GMAW tends to produce cleaning action.

• A. True
• B. False
• C. Only at low currents
• D. Only with certain gases

Answer: (A)

Polarity in GMAW changes how the arc interacts with the surface oxides on the base metal. When the electrode is positive (DCEP), the arc conditions tend to disrupt and volatilize the oxide film more effectively at the weld surface, helping to expose clean metal for fusion. This cleaning action means oxides are more readily burned away by the arc, reducing oxide inclusions in the weld area. Shielding gas still plays a role in preventing reoxidation, but the polarity-determined arc behavior makes oxide removal more likely under DCEP across typical steels and similar metals with oxide films. The strength of this cleaning effect can vary with material, current level, and gas, but the tendency is generally observed, so the statement is true.