Mechanical properties of underwater wet welded marine steel plates using different low hydrogen electrodes

Underwater wet welding is one option that can be applied in overcoming underwater emergencies, especially in the case of saving the ship damage. Although the results of the weld with SMAW method are between fair and good, but it is still feasible to be used. It is due to the fact that this method is the most popular, economical and efficient for wet underwater welding. In this study, KI-A36 steel plate material was used and implemented for underwater wet welding using E7016 and E7018 electrodes. Both types of electrodes are low hydrogen electrode group that can be found easily in the market. This study investigated the mechanical properties of the underwater welding of marine steel plate by using E7016 and E7018 low hydrogen electrodes. The welding method type with heat inputs of 0.8kJ/mm, 1.5kJ/mm and 2.5kJ/mm were performed at depths of 5m and 10m. The results of radiography test showed that specimen welded at depth of 5m and 10m indicated the occurrence of incomplete penetration defects. It might be due to the influence of considerable pressure and the higher cooling rate that the molten weld could not penetrate completely to the parent material. Nevertheless, this study revealed the absence of porosity in underwater wet welding by applying both E7016 and E7018 electrodes. Tensile test results also showed insignificant decline in the strength of underwater welding results and a considerable elongation. The hardness of welded samples showed insignificant difference between base metal, HAZ and weld metal. The use of E7016 electrodes with the heat input of 1.5kJ/mm provided the optimum mechanical properties of underwater wet welds.