Which statement describes short-circuit transfer and spray transfer in GMAW, and which is more common for thin steel body panels?

• A. Short-circuit transfer uses high voltage and few short circuits; spray transfer uses many short circuits; short-circuit is more common for thin panels.
• B. Short-circuit transfer uses frequent short circuits at low voltage; spray transfer uses sprayed molten metal with higher voltage; short-circuit is more common for thin steel panels.
• C. Short-circuit transfer uses a sprayed molten metal; spray transfer uses short circuits; both are used for thin panels.
• D. Short-circuit transfer uses continuous long arcs; spray transfer uses rapid melting.

Answer: (B)

In GMAW, how the molten metal transfers from the wire to the weld pool shapes both heat input and control, which is crucial for thin sheets. Short-circuit transfer happens when the electrode tip touches the weld pool and separates repeatedly, creating many small short circuits at a relatively low welding voltage. This mode gives you lower heat input and great arc control, making it well suited for thin materials like body panels where you want to minimize burn-through and distortion.

Spray transfer, in contrast, uses a higher current and voltage to produce a continuous spray of tiny molten metal droplets from the wire to the weld. It delivers a higher deposition rate and a smoother bead, but also more heat into the work, which can be challenging to manage on thin sections.

So the statement that short-circuit transfer involves frequent short circuits at low voltage, spray transfer involves a sprayed molten metal at higher voltage, and that short-circuit transfer is more common for thin steel panels is the best description.