Evaluation of the Impact of Corrosion Attack in Carbon Steel C-1040 Marine Piping System in Two Media

Abstract

The focus of this study was to investigate the impact of corrosion attack in carbon steel C-1040 marine piping system using weight loss method. Two carbon steel specimens (coupons) of cylindrical shape were selected and weighed before they were exposed to two different test solutions (corrosion media) at a concentration of 0.2M and 0.04M in seawater and freshwater respectively at room temperature for eight weeks. The weight loss was taken as the difference in the weight of the coupons before and after immersion in the two different test solutions. The corrosion rates of the coupons were calculated from the weight loss obtained. The experimental result from weight loss method was calculated using engineering equation solver (EES). The weight loss and rate of corrosion of the two coupons varied as higher corrosion rate and weight losses were observed in coupon 2. The weight loss and corrosion rate in 0.2M concentration of coupon 2 in seawater environment increased from 0.04 g to 0.53 g, 0.007133 mmpy to 0.0181 mmpy while coupon 1 showed an increase from 0.01 g to 0.25 g, 0.0035 mmpy to 0.005573 mmpy was observed in 0.04M concentration in freshwater environment. This shows that carbon steel metal was more susceptible to corrosion attack in seawater environment than in the freshwater environment. The micrograph results of coupon 2 before and after immersion in 0.2M of seawater for about 1344 hrs showed evidence of uniform (general) corrosion as the coupon surface was rough and jarring. The grain boundaries of the surface morphology also revealed general corrosion effects on the coupon after immersion as the film present on the surface was cracked as a result of corrosion impact.