The structure of the underwater construction will gradually be damaged, when the damage is in an emergency condition, it is necessary to repair and install the structure using welding techniques below the surface of the water. Corrosive seawater environment is considered in the selection of welding currents to minimize damage due to high corrosion rates in the weld results. The purpose of this research is to determine the differences in corrosion rates of the underwater Shielded Arc Welding (SMAW) using E7014 electrodes with a diameter of 3.2 mm on JIS SS400 steel plate material with current variations of 155A, 165A, and 175A. Observations were made by Open Circuit Potential (OCP), weight loss, microstructure observation and macroetching test. The OCP test shows that, the lowest corrosion rate was obtained from the variation of welding current strength using 155A of the welding current, where the corrosion rate is 0.10089 mm/year. Microstructural observations exhibit the uniformity structure of the three-welding regions for each of the welding variation. The higher of welding current make the larger Heat Affected Zone (HAZ) area and this is directly proportional to the produced corrosion rate. Hence, it can be concluded that HAZ is highly influence the difference of the produced corrosion rate. As a result, the information about the effect of current variations and plate thickness on the corrosion rate of JIS SS400 steel in underwater SMAW welding can be delivered.
STUDY OF THE UNDERWATER SHIELDED METAL ARC WELDING (SMAW) CURRENT EFFECT ON CORROSION RATE OF JIS SS400 STEEL
2019 - ITK