Hydraulic machinery operating on sediment-laden rivers suffers from sediment erosion

which causes the deformation of flow passages

reduction of hydraulic efficiency

and even shutdown of the unit. By taking advantage of a rotary jet device

this study conducts a sediment abrasion and erosion experiment on materials used for hydraulic turbines under different impact velocities and impact angles

and investigated the measured sediment abrasion characteristics using the weight loss method along with microstructure analysis. The results indicated that for three types of materials

the weight loss and the facilitation of cavitation on sediment abrasion take an exponential increase with impact velocity

along with the increase in the surface roughness

the size of cutting scratches as well as cavitation pits. For all materials

the impact angles that maximize weight loss are roughly 40° and 45° for abrasion and erosion respectively. The vertical impact effect and horizontal removal of particles match best at 45° impact angle

and the particle impact forms disc-shaped pits of which the surface lip edges are removed by horizontal cutting

resulting in significant weight loss. At 45° impact angle

cavitation induced by the jet nappe is the most severe

and the combined abrasion-erosion damage causes relatively deep pits on the material surface

which leads to the weight loss twice of that in abrasion test.