Corrosion Behavior of Buried Carbon Steel Pipeline In Iraqi Soil in Different Sodium Chloride Concentrations

摘要

In this work, external corrosion behavior of oil pipeline was evaluated using potentiodynamicpolarization curves. The corroding metal was carbon steel. To estimate corrosion by potential and currentdensity of carbon steel, different concentrations of sodium chloride were chosen and prepared in the laboratoryto simulate external condition of buried carbon steel pipeline in Iraqi soil. NaCl concentration in Iraqi soil wastested by taking samples from different areas, from north to south of Iraq. pH of soil samples were ranged fromacidic to basic. Temperature of prepared solutions was constant at 350 C which Iraq environment is hot most ofthe year. Carbon steel coupon of (ASTM A179-84A) type was used as the studied metal. Potentiodynamicpolarization curves, of potential vs. log current density, were obtained using M Lab Multi-ChannelPotentiostat/Galvanostat. The results revealed the behavior of carbon steel in different chloride concentrations,pH, and relativelyhightemperature. The rate of corrosion increases with the increase in chloride concentration,and decreases with acidity decrease. Triple relationship between these parameters was studied.