Every quality weld begins with selecting the correct current type, polarity, and control mode. Even with the best welding procedure and skilled welder, an incorrect polarity can result in poor penetration, excessive spatter, lack of fusion, or distortion.
☆Key Takeaways:
♦AC (Alternating Current)
• Excellent oxide cleaning action.
• Commonly used for GTAW (TIG) welding of aluminium and magnesium.
• Suitable where alternating polarity is required.
♦DC+ (DCEP – Electrode Positive)
• Deep penetration.
• Ideal for root passes and thicker materials.
• Higher heat concentration on the electrode.
♦DC− (DCEN – Electrode Negative)
• Higher deposition rate.
• Shallower penetration with a wider weld bead.
• Best suited for thin materials and surfacing applications.
☆Current Control Modes
♦ Constant Current (CC)
• Used in SMAW, GTAW, and PAW.
• Maintains stable current for consistent penetration and arc stability.
♦ Constant Voltage (CV)
• Used in GMAW (MIG/MAG), FCAW, and SAW.
• Maintains stable arc length and smooth wire feeding.
♦ Remember:
√ Correct current selection improves weld quality.
√ Proper polarity minimizes welding defects.
√ Always follow the applicable WPS and electrode/wire manufacturer’s recommendations.
Post time: Aug-07-2026