Synergistic Erosion-Corrosion Behavior of API X120 Steel

Abstract

The corrosive nature of fluid (oil and gas) and the presence of solid erodent particles in it causes the pipelines to experience severe erosion and corrosion during the transportation process. In this study, erosion-corrosion behaviour of API X120 steel was investigated using aluminium oxide particles (60 µm) as erodent and 3.5% (wt. %) NaCl aqueous solution saturated with carbon dioxide as a corrosive medium. Effect of particles speed at an impact angle of 90° and the synergistic effect of erosion-corrosion were investigated using weight loss, potentiodynamic polarization technique, and surface analysis. During the corroison-erosin process, the formed iron carbonate layer (during corrosion process) is removed by the erosive erodent particles (erosion process) which results in high corrosion rate and high surface roughness. Furthermore, during the erosion-corrosion process, a significant effect of corrosion on erosion at lower particle's speed is noticed while at higher particle speed erosion has a dominant influence on the corrosion as identified in the Synergy/Total erosion-corrosion ratio (S/T ratio). Finally, our results indicate a simultaneous activation of erosive and corrosive phenomena during erosion-corrosion of API X120 steel.