Investigation on wall thickness reduction of hydropower pipeline underwent to erosion-corrosion process

Abstract The present investigation was carried out to study the erosion-corrosion analysis in the hydropower pipeline of a Francis turbine. Testing was performed on a mild steel pipe having a diameter of 6 in.. An extensive set of experiments was carried out to test the properties of the erodent and the worn-out pipeline. Experiments were carried out using the sand-water suspension of concentration, ranging from 5000 to 20,000 ppm. The physical properties such as size and morphology of the sand particles as well as settling concentration of sand-water suspension were examined by the various bench-scale tests. The SEM-EDS techniques were used to study the morphological and chemical composition of the pipeline. Visual inspections depicted that the major deterioration occurred at the bottom half of the pipeline. Also, the lower surface of the pipeline seems underwent to high erosion and corrosion as compared to the upper surface of the pipeline. Results show that the erosion-corrosion process causes the wall thickness reduction of the horizontal pipeline. However, the properties of sand namely size, shape and static settled concentration of particles play a key role in the erosion wear of the pipeline. The solid particles of the sand eroded the pipeline material, which results in pits, craters, and cutting wear mechanisms on the pipeline surface. It can be said that the use of pipelines having an uneven hardness and lack of established inspection norms results in unexpected failures.