Slurry erosion-corrosion of 90° AISI 1018 steel elbow in saturated potash brine containing abrasive silica particles

Erosion-corrosion is frequently encountered in pipelines used in potash processing equipment and it may be a severe problem, causing rapid material degradation if the slurry flow velocity and solid concentration are high. In this study, the interaction between erosion and corrosion of 1018 steel 90 degrees elbows (2.54 cm schedule 40 - long radius) was investigated in a continuous flow loop. Experiments were conducted using a slurry consisting of saturated potash brine and silica sand. The effects of solid concentration and flow velocity on erosion-corrosion damage of the steel elbow were investigated. The results indicated that increasing flow velocity and solid concentration increased the mechanical effects of particles on the tested elbows and hence increased the erosion-corrosion rates of the elbows. It was observed that there was a 56% synergy between erosion and corrosion at 2.5 m/s, but the synergy level decreased to 11% at 4.0 m/s.