GMAW transfer mode determines how filler metal crosses the arc. The four modes — short-circuit, globular, spray, pulsed — produce different penetration profiles, different deposition rates, and different defect risks. AWS D1.1:2025 treats each as a distinct essential variable. Mixing them on one WPS is one of the most common GMAW audit findings.

The four transfer modes, quick reference

Short-circuit transfer. Wire dips into the puddle, shorts out, melts off. Low heat input, easy to control, limited penetration. Common on thin sheet and root passes (with caveats). Restricted under Clause 5 for PJP groove welds.

Globular transfer. Large droplets fall under gravity. High spatter, limited control. Mostly used on heavy thick-plate work with CO2 shielding. Rarely the WPS of choice.

Spray transfer. High current, fine droplet stream. Deep penetration, smooth weld, no spatter. Standard for structural production above ~200 A. Not practical out-of-position at standard parameters.

Pulsed transfer. Programmable pulse waveform produces spray-like droplets at lower average current. All-position capable. Common on high-end production with synergic power supplies.

Why mode matters on the WPS

Three reasons:

  1. Penetration changes with mode. A WPS that's safe for spray transfer may produce lack-of-fusion in short-circuit on the same wire.
  2. Position capability changes with mode. Spray won't do vertical-up without pulse modulation. Short-circuit will, but with cold-lap risk.
  3. Essential variable classification. Per Table 6.6, modes are distinct. Requalification is triggered by mode change.

Documentation on the WPS

The transfer-mode block is mandatory:

Electrical characteristics:
  Current: DC
  Polarity: DCEP
  Transfer mode: SPRAY
  Amperage range: 200–320 A
  Voltage range: 24–30 V
  Wire feed speed range: derived from amperage

For pulsed:

  Transfer mode: PULSED
  Pulse program: [synergic program name + serial]
  Peak current: 380 A
  Background current: 80 A
  Frequency: 150 Hz
  Duty cycle: 35%

The synergic program identification matters because two power supplies with the same brand may produce different pulse waveforms on the same program number. Be specific.

Prequalification rules under Clause 5

  • Short-circuit transfer — prequalified for fillet welds; excluded from PJP groove welds
  • Globular transfer — prequalified per Clause 5
  • Spray transfer — prequalified per Clause 5; position restricted (flat and horizontal only at standard parameters)
  • Pulsed transfer — prequalified for all positions if the synergic program produces sound welds; the WPS must document the program

The most common audit findings

  1. WPS doesn't declare transfer mode. "GMAW" alone is ambiguous.
  2. Short-circuit declared on a PJP groove weld WPS while claiming prequalified status. Direct fail.
  3. Spray transfer claimed in vertical-up position. Not prequalified for spray at standard parameters; either qualify by test or switch to pulsed.
  4. Pulsed WPS without synergic program identification. Auditor cannot verify the pulse waveform.
  5. Transfer-mode change in production (welder switches from spray to short-circuit to deal with thin plate) without a separate WPS for short-circuit. Mode change is essential.

The voltage / amperage signature of each mode

A useful diagnostic: for a given wire diameter, each mode has a characteristic V/A region.

For 0.045 in carbon-steel wire, approximate ranges:

  • Short-circuit: 16–22 V, 80–180 A
  • Globular: 22–26 V, 180–250 A
  • Spray: 26–34 V, 200–400 A
  • Pulsed: programmable

A WPS that lists 18 V and 250 A is internally inconsistent — those parameters don't correspond to any single mode for a 0.045 in wire. The rule engine flag is: voltage/amperage outside the declared mode's expected envelope.

How to organize a GMAW library

Most structural shops carry three GMAW WPSs:

  • One spray-transfer WPS for 1G/2G/1F/2F production on thick plate
  • One pulsed WPS for all-position production on medium plate
  • One short-circuit WPS specifically for fillet welds on thin sheet (where the transfer mode is appropriate)

That covers most production. Trying to consolidate to one ambiguous "GMAW" WPS is the trap.