With SMAW, direct current electrode negative (DCEN) polarity gives deeper penetration and slower electrode melting rates.

• A. Shallower penetration and faster electrode melting rates
• B. No penetration
• C. Higher energy efficiency
• D. Deeper penetration and slower electrode melting rates

Answer: (D)

In SMAW, polarity affects where the arc heat goes. With the electrode as the negative (DCEN) and the workpiece as the positive, most of the heat concentrates in the base metal rather than the electrode. That heat distribution drives deeper penetration into the joint, while the electrode itself melts more slowly, reducing the rate at which filler metal is deposited from the electrode. So you get a weld that penetrates deeper while the electrode consumption is slower. If you were to reverse the polarity (electrode positive), more heat goes into the electrode, increasing its melting rate and producing shallower penetration.