Investigating Corrosion of ASTM A283 Grade C Carbon Steel and E7018 Welding Electrode in Persian Gulf Seawater

Investigation of Persian Gulf seawater corrosion effect on the carbon steels and welded pieces used in construction of metallic storage tanks is important from this point of view that this investigation may result in using this seawater to do hydro test of these tanks. If the results of this evaluation be positive, it will have lots of economic and environmental advantages. In order to achieve this target in this study, at first a 15 mm thickness plate of ASTM A283 Grade C low carbon steel was welded by E7018 electrode then quality controlled by radiography test and its microstructure evaluated by macro and micro etch tests and also hardness test was done for it. Furthermore chemical composition, pH, conductivity and SRB amount within the water has been measured too. Then corrosion rates for each one of these mentioned steel and electrode in Persian Gulf seawater were measured by electrochemical method of linear polarization resistance and also immersion test. Then corrosion product and corroded surface were analyzed by EDS and SEM methods. Results of polarization and immersion tests proved that E7018 electrode is anode compared to ASTM A283 Grade C steel and this result was confirmed by SEM images.