Which of the following is true about E6010's polarity and penetration characteristics?

• A. It uses DC reverse polarity and provides deep penetration
• B. It uses AC and shallow penetration
• C. It uses DC straight polarity and deep penetration
• D. It uses AC and deep penetration

Answer: (A)

Understanding how polarity affects the weld is key here. Polarity determines where most of the heat is deposited: toward the workpiece or toward the electrode. E6010 is a cellulose-coated electrode known for its deep-penetration root welds. When you run it with direct current in reverse polarity, the electrode is positive and the workpiece behaves as the negative side. This setup concentrates more heat into the base metal, driving deeper penetration into the joint and helping burn through surface oxides or contamination. That combination—DC with reverse polarity—produces the characteristic deep penetration that E6010 is chosen for.