The mechanism of erosion-corrosion of API X65 steel under turbulent slurry flow: Effect of nominal flow velocity and oxygen content

Erosion-corrosion (E-C) of carbon steel API 5L X65 by mineral quartz and alumina slurry is studied to understand the mechanism of corrosion-accelerated material's degradation. A rotating cylinder electrode is employed to simulate the E-C damage and for electrochemical characterization, observed at different flow velocities and contents of dissolved oxygen (DO). Microstructural inspection using SEM and EBSD reveals the extension of the work-hardened layer and other features of the sub-surface. The effect of nominal flow velocity is shown to be associated with an increment in average particles' impact angle and frequency of impacts at the faster flow. The increase in DO availability is shown to promote localized-type corrosion different from pitting, demonstrating the mechanism of erosion-enhanced corrosion.