Influence of swirl number and incidence angle on erosion-corrosion behavior of API 5L X-52 steel under swirling jets

The effect of swirl velocity on erosion-corrosion damage was studied into the context of pipeline elbows and bends transporting slurries, focusing on swirl number and incidence angle. Tests were conducted on API X-52 steel coupons as target material and carried out at 5 m/s and four different swirling numbers 0, 0.1, 0.2, and 0.3. The corrosive slurry consisted of a brine solution with 2 g L−1 of NaCl and suspended aluminum oxide particles. The impinging angles employed were 30°, 45°, 60° and 90°. Corrosion rates were obtained from LPR measurements. Pitting corrosion and corrosion products were characterized by means of SEM/EDS techniques. The experimental results showed that the swirl intensity enhances the pit growing, and the angle of incidence is not a relevant factor on pitting corrosion behavior. The maximum corrosion rate was observed at high swirl intensities, making clear the severity of swirl conditions.