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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. [ABSTRACT FROM AUTHOR]

Underwater welding is an important role in the rescue of ships and underwater structures, in case of emergency. In this study, the marine steel plates used are AH-36 steel as parent material. This type of steel is included in the High Strength Low Alloy (HSLA). Electrodes used for welding AH-36 steel plates are commonly the E6013 and E 7024 which are the type of based rutile electrodes. Those electrodes are widely available on the market and they would be compared with the original electrode for underwater which is the type of E7014 with the trade name of Broco UW-CS-1. Welding method used is Shielding Metal Arc Welding (SMAW) with the variation of 5 m and 10 m underwater depth and also varied with the electric current of 120A, 140A and 250A. It was found that hardness value of increased in the area of weld metal and HAZ. HAZ also tends to have the highest hardness compared to both of weld metal and base metal. Non destructive test by radiographed test (RT) on welds showed that there are found welding defects in the form of incomplete penetration on all variations of welding parameters, but there is no porosity defect detected. The results of the hardness tests of underwater wet welded steel plates show that the hardness value of both rutile electrodes (E6013 and E 7024) is apparently similar hardness value compared with the existing commercial electrode (E7014 of Broco UW-CS- 1). The tensile test results of underwater wet welded steel plates show that the use of rutile electrode of E6013 gives a better tensile properties than other rutile electrodes. [ABSTRACT FROM AUTHOR]

Current post-information era promotes rapid technology development which accelerates the information processing and storing electronics evolution. The consequence of such rapid evolution is the current technology obsolete faster as well as the older technology became vintage. This study aims to explore the possible mechanical utilization of CD-R as an obsolete information storage media in current era. Here, the ethanol soaked CD-R capability to affects the hydrogen evolution reaction (HER) was observed through saltwater electrolysis test. The CD-R was prepared by loading interchanging bytes (1010-1010) of information in empty, half-loaded, and fully-loaded fashion. The morphological characterization and digital imaging technique also performed to reveal the underlying mechanism. The fully-loaded loaded CD-R has stacked pits which forms elongated craters and concentrates the Ag particles distribution on the pits. As results, the HER of fully-loaded disc is 394291.19ppm which about 100000ppm higher than half-loaded and 200000ppm than empty disc. The fully-loaded disc superior HER is due to the higher surface polarity gradient on data layer and the Nano-voltage generation through diffusion on concentrated Ag particles. Conclusively, digital information stored on a disc is utilizable to control hydrogen production process through electrolysis. [ABSTRACT FROM AUTHOR]