Table 1 Summary of metal transfer mode evolution

Droplet transfer

Free flight, short circuiting. A slag mode is defined for other arc welding (SAW)

IIW (1976), referred by Lancaster (1984) as Anon

Droplet transfer and droplet size

Categorization by level of current and drop size current: moderate current (globular), relatively high current (spray), high current (stream), very high current (rotating)

Lancaster (1984)

Associated transfer mechanism

Mechanisms: (1) natural metal transfer, (2) controlled transfer techniques, and (3) extended operating mode techniques

Norrish (2003)

Transfer mechanism and labelled with alphabet letters

Suggested confining the classification to natural and controlled transfer modes. In addition, these authors proposed an extra fixed alphabetic label for each ‘fundamental’ metal transfer mode (A, short-circuiting; B, globular; C, pulsed; D, spray; and E, rotating)

Lucas et al. (2005)

Current range, sketch illustration, and type of consumable electrode

Droplet transfer during GMA welding with solid wire and FCW has been observed in detail and the transfer

Izutani et al. (2006)

The range of current is provided for each transfer mode

Sketch illustration of the mechanisms and an alphabetic associated with number classification

A, short-circuiting; B, globular; C, spray. Similar approach using alphanumeric labels (A, B1, B2, C1, C2, and C3).

Iordachescu and Quintino (2008)

The controlled processes classification and defined two types of controlling processes, either simple controlled processes or real-time controlled processes.

Metal transfer-natural transfer, controlled transfer and mixed mode transfer, oriented to scientific personnel

Metal transfers are illustrated by a sequence of droplet transfer. Corresponding main forces governing the metal transfer are indicated for each case.

Scotti et al. (2012)

Metal transfer modes are categorized in a flow chart: natural transfer, controlled, and interchangeable transfer.