Spray

Spray
Spray transfer GMAW was the first metal transfer method used in GMAW, best suited for welding aluminum and stainless steel while employing an inert shielding gas and a relatively thick electrode. In this variation, molten metal droplets (with diameters smaller than the electrode diameter) are rapidly passed along the stable electric arc from the electrode to the workpiece, essentially eliminating spatter and resulting in a high-quality weld finish. However, high amounts of voltage and current are necessary, which means that the process involves high heat input and a large weld area and heat-affected zone. As a result, it is generally used only on workpieces of thicknesses above about 6 mm (0.25 in). Because of the large weld pool, it is often limited to flat and horizontal welding positions, but when a smaller electrode is used in conjunction with lower heat input, its versatility increases. The maximum deposition rate for spray arc GMAW is relatively high; about 60 mm/s (150 in/min).