Experimental erosion-corrosion analysis of friction stir welding of AA 5083 and AA 6061 for sub-sea applications

Aluminum Alloys find extensive use in sub-sea installations, marine applications that include deep sea mining and in various naval underwater requirements due to their excellent corrosion and wear resistant properties. Friction Stir Welding (FSW) is a solid - state welding process adopted for the production of AA 5083- AA 6061 joints for structures of deep sea crawlers and other sub-sea applications. The present work throws light on the parameters relevant to the sub-sea which lead to the maximum erosion corrosion behavior (mass loss) of friction stir welded AA 5083- AA 6061 joints produced using 6 mm thick plates. The study was conducted in a slurry jet erosion apparatus, in which the erosion-corrosion response of FSW joints of AA 5083 and AA 6061 for various combinations of pH values, velocity of impingement and orientation conditions was evaluated, using Taguchi method. The Signal to Noise (S/N) ratio response for the erosion-corrosion behavior is presented based on experimental results. The results showed the pH as the most influencing parameter which affected the erosion corrosion behavior, contributing upto 86.89%, followed by 4.12% and 4.41% respectively, by the velocity and angle of impingement. ANOVA analysis was performed for the examination of the differences among group means.