Study on The Material Factor in Erosion-Corrosion

Many corrosion problems involve situations where the environment moves. An increase in the relative motion between a corroding metal or alloy and its environment can increase corrosion rates by removing protective films or by increasing the diffusion or migration of deleterious species. In oil and gas industry, erosion-corrosion is a natural potential hazard associated with production and transportation facilities. This project is based on one of the problem that had occurred in a refinery plant, PETRONAS Penapisan (Melaka). Erosion-corrosion affects the steel impeller of a pump. When the impeller is subjected to metal loss that occurs gradually, the performance of the equipment is at risk. The performance of a pump depends on the impeller that accelerates the moving fluid in it. It is important to study the erosion-corrosion and the factors of erosion-corrosion on the impeller especially on the material factor in erosion-corrosion. The project is aimed to study the susceptibility of aluminium alloy and carbon steel in different chemically defined environment. Rotating disk test is used to study the erosion-corrosion of aluminium alloy and carbon steel at different environments which are in tap water, tap water with 10g sand particles of sizes 0.5mm and in seawater. From the tests conducted, the final weight of each specimen has increased except for the aluminium alloy in pure tap water that has decreased in weight. The weight increase is due to the mechanically mixed layer (MML) that formed on aluminium and also rust that resulted from corrosion that formed on carbon alloy. From the test it can be concluded that different materials and different environment results in different erosion-corrosion rate.