The Influence of Seawater Velocity to the Corrosion Rate and Paint Degradation at Mild Steel Plate Immersed in Sea Water

Abstract

Mild steel is one of the materials that used to build ships and other marine construction which go through current, streams, waves with different speed. The aim of this study is to investigate the effect of seawater flow speed on the corrosion rate of mild steel and the paint thickness degradation. The simulation is done at laboratory scale using mild steel coupons exposure under different flow velocity of seawater that are 2 m/s, 4 m/s, 6 m/s and as control is used stationary flow, 0 m/s. Electrochemical impedance spectroscopy is used to determine the corrosion rate occurred on the coupons plate surface and its paint degradation as function of immersion time. Scanning electron microscopy also is used to observe the plate surface rust and the damage of paint which occurred during the experiment. Experiment is run for thirty days for every water flow speed and the data is taken every ten days. The result of this study revealed that the corrosion rate and paint degradation are increased by the increasing of water flow velocity which is proposed to validate seawater flow rate as parameter that increased the paint damage and corrosion rate of mild steel plate.