4.3.2 Equipment
The GMAW process is most often used in the semi-automatic mode, that is, a welder holding the gun
moves and guides it along the weld seam while depositing the weld metal. This also gives him the
flexibility to manipulate the gun to maintain appropriate weld pool shape and wetting and fusion along
the side walls. A typical gun is 250 to 375 mm in length and provides the means to supply current,
continuously feed the wire and provide the shielding gas to protect the arc and the molten weld pool
(see Figure 4.10). Some guns rated for higher currents or higher duty cycles may also have provision
for water cooling.