Experimental investigation of sediment erosion of turbine steel used in Bhilangana-III power-plant

Turbines located in the geographical regions of Africa, Himalayan, South-East Europe and South America are subjected to erosion due to sediments flowing with water. The extent of damage due to erosion depends on the material property and the impinging condition of particles. In this work, experiments have been performed in a high speed pot tester on the steel used for Francis turbine of Bhilangana-III power-plant. The erosion rate is determined by mass loss of the specimens rotating inside the pot. The erosive wear behavior of turbine steel is evaluated at high velocities of 27 m/s and 32 m/s by varying the orientation angle from 15 to 90 degrees. The mean particle size and sediment concentration are selected as 300 µm and 3000 ppm, respectively. The erosion rate of turbine steel is increased with impact angle upto 30 degree and then decreased with a further increase in impact angle till 90 degree. The effect of variation of particle impingement velocity on erosion rate behavior of turbine steel is determined for the velocity range of 13-32 m/s. The erosion rate increased with increase in the velocity. Further, the mechanism of erosion with the variation in velocity is analyzed at different impact angles using SEM micrographs of worn out samples.