Metal Transfer Modes in GMAW using 0.9 mm Mild Steel Wire and CO2 Shielding Gas

Which modes of metal transfer are possible with GMAW using 0.9 mm (0.035") mild steel wire and carbon dioxide shielding gas?

a) spray and globular.

b) globular and short-circuiting.

c) short circuiting and pulsed spray.

d) spray and pulse spray.

Final answer: The possible modes of metal transfer with GMAW using 0.9 mm mild steel wire and carbon dioxide shielding gas are spray and pulse spray. (Option D)

Explanation: The modes of metal transfer possible with GMAW using 0.9 mm (0.035") mild steel wire and carbon dioxide shielding gas are spray and pulse spray. In the spray mode, small droplets of molten metal are transferred across the arc in a spray-like fashion. This mode is commonly used for higher current applications and provides good deposition rates and low spatter. In the pulse spray mode, the wire is rapidly pulsed between high and low current levels, resulting in controlled droplet transfer and improved control over the welding process.