Which polarity provides better penetration in FCAW?

• A. Direct current electrode negative (DCEN)
• B. Alternating current
• C. Direct current electrode positive (DCEP)
• D. Pulsed DC

Answer: (C)

Polarity controls where most of the arc heat goes, and that directly affects how deeply the weld fuses into the base metal. In direct current electrode positive, more heat is delivered to the workpiece, driving deeper penetration and better fusion with FCAW. If the electrode is negative, more heat stays at the electrode and the penetration tends to be shallower. Alternating current keeps flipping polarity, so the heat input to the base metal isn’t consistently higher, which reduces the chance of deep penetration. Pulsed DC can limit overall heat input and help control the bead, but it doesn’t inherently maximize penetration like steady DCEP does. So, directing the arc heat into the workpiece with direct current electrode positive yields the deepest penetration.