Moisture in the electrode coating can cause porosity in GMAW.

Moisture in the electrode coating can cause porosity in GMAW.

• A. True
• B. False
• C. Only with direct current
• D. Only with alternating current

Answer: (A)

Moisture in the electrode coating releases hydrogen when the coating is heated in the welding arc. That hydrogen gas can form bubbles in the molten weld pool and get trapped as the metal solidifies, producing hydrogen porosity in the weld. This can happen with damp or poorly dried electrodes, especially flux-coated types, and isn’t prevented by the type of current used. The formation of porosity from moisture occurs with both direct current and alternating current, so the moisture-related porosity is possible regardless of polarity. So the statement is true.