The gas metal arc welding (GMAW) process uses __________ to melt metal wire and fuse it with the base metal being welded.

• A. Electricity
• B. Gas shielding
• C. Hydraulic pressure
• D. Mechanical force

Answer: (A)

Gas metal arc welding relies on electrical energy to create the heat that melts the filler wire and fuses it to the base metal. A power supply sends current through the consumable wire electrode and across the gap to the workpiece, producing an electric arc. that arc is hot enough to melt the wire tip and a portion of the base metal, allowing the melted filler to mingle with the base metal and then solidify to form the weld joint. The shielding gas isn’t the melting mechanism; it protects the molten pool from the atmosphere so the weld stays clean, but it doesn’t supply the heat. Hydraulic pressure or mechanical force don’t provide the energy needed to melt or fuse the metals in this process.