In-situ electrochemical testing and fluid dynamics simulation of pipeline defects under flow accelerated corrosion

The pipeline defects of flow accelerated corrosion (FAC) on the corrosion behaviors and localized corrosion mechanisms on different locations of the depressions and the welded joint with weld reinforcements were investigated using wire beam electrode (WBE) techniques and fluid dynamics simulations. The results revealed that the swirling vortex inside the depression and the local jet impact by the fluid separation in the weld reinforcement can accelerate the localized corrosion. Also, the depressed upper and trailing edge regions and the weld toes on both sides of the weld reinforcement experience considerable pressure fluctuations, enhancing interfacial mass transfer processes and inducing cavitation for severe localized corrosion failure. Furthermore, the galvanic corrosion strength factor (g) indicated an enhanced susceptibility of localized corrosion in depression and welded joints with weld reinforcement.