Abstract： Underwater wet fluxcored arc welding (FCAW) experiments were conducted in a hyperbaric chamber which was used to simulate different water depths. Relative standard deviation reciprocals of arc voltage were used as an index of welding arc stability. The influences of correlations between arc voltage and welding current at different water depths on arc stability were analyzed. From the point of view of the wire feeding  melting system, the influences of voltage and current correlations on arc stability were analyzed. The correlations of arc stability and arc voltage were numerically fitted by a second order function and then the optimal correlations of arc voltage and welding current were obtained. The results show that the optimal correlation curves of arc voltage and welding current for underwater wet welding are a series of ascending curves, which go upward with the increase in water depth. The arc stability depends on the correlations of arc voltage and welding current, and does not simply decline with the increase in water depth. The arc voltage corresponding to a single welding current of underwater wet welding should be increased as the water depth increases.
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