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8 A variation of this spray arc technique is known as ”pulsed” spray welding. In pulsed spray arc welding, the current is varied between a high and low value. The low level of current is below the transition current while the high level is well into the spray arc region. Metal is only transferred to the work during the period of high current. Usually one droplet is transferred during each high current pulse. Figure 1-4 depicts the welding current pattern used in pulsed spray arc welding. In the United States, only 60 or 120 pulses per second are used. Because the peak current is in the spray arc region, arc stability is similar to that of conventional spray arc welding. The period of low current maintains the arc and serves to reduce the average current. Thus, the pulse spray technique will produce a spray arc at lower average current levels than are required for conventional spray arc welding. The lower average current makes it possible to weld thinner gauge materials with spray type transfer using larger sized wire electrodes than otherwise possible. Pulsed spray arc welding can also be used for out-of-position welding of heavier sections. Figure 1-4 - Pulsed Spray Arc Welding Technique