In GMAW, what primarily supplies the energy to melt the metal filler wire?

• A. Electricity
• B. Gas shield
• C. Hydraulic pressure
• D. Mechanical friction

Answer: (A)

In Gas Metal Arc Welding, the heat that melts the filler wire comes from the electric arc created by the welding power source. The current flows through the consumable electrode and into the workpiece, and the arc concentrates a huge amount of energy at the tip of the wire. That energy raises the temperature high enough to melt the filler wire, which then adds material to the weld pool as it is fed in. The shielding gas protects the molten metal and arc, but it does not supply energy. Hydraulic pressure and mechanical friction aren’t involved in melting the wire in this process.