Study of Corrosion Behaviour on Welded Alumunium Alloy 6061 Plate Immersed in Natural Seawater

Abstract

Aluminum 6061 is an example of marine grade alloy that contain up to 1.2 %of magnesium and 0.80% of silicon as a major alloying element that provide good corrosion resistance properties. However, under the certain circumstances, aluminum 6061 will experience corrosion when exposed to aggressive corrosive agents. The aim of this study is to determine the effect of exposure level and duration of exposure on the corrosion behavior of welded aluminum alloy 6061. High quality weldment and poor weldment specimen were used for immersion test in 3.5% sodium chloride (NaCl) solution as simulated for natural seawater. Three different methods were applied which are fully immersed without aeration, fully immersed with aeration and semi immersed throughout the immersion test. The immersion test result showed that the specimen with the presence of defects on weldment and conducted in semi immersed with the aeration condition for 1680 hours (70 days), has obtained the highest corrosion rate which is 0.4086 mm/year.