Correlating study of bubble phenomenon, electrical signals and weld metal in underwater wet welding with covered electrodes

The bubble phenomenon in underwater wet welding is very important in the weld's final quality. A good understanding of the formation and collapse of the bubbles with the knowledge of the welding parameters behavior along the process can improve the practices used in the underwater welding and, consequently, improve the final weld quality. To understand and try to correlate the phenomenon of growth, detachment and frequency of the bubbles with the electrical signals along the welding process this work was done. Three commercial covered electrodes, E6013, E7024 e E7018 were used to made beds on plate in a depth of 0,50 m. To visualize the formation, detachment and counting of the bubbles a high speed camera was used to record the process, together with electrical signals acquisition. So it was possible try to correlate the bubble frequency with the electrical signals observed along the process and those with specimen macrographs. That was observed in the currents data that the average number of variations under 5% of the average current is similar with the average rate of bubbles detachment. Therefore was concluded the possible relationship of the bubble detachment with a determined variation in the current.