Sammendrag
Mass loss of inner wall surface due to particle impact, also referred as erosive wear, is a common challenge encountered in industrial pneumatic conveying systems. Hard bulk material tends to interact with the surface and ultimately results leakages into the surrounding. Previous studies have shown that erosion is a process involving many parameters and a combination of several wear mechanisms. Erosion rate highly depends on surface properties, particle properties and flow properties. Among them, particle size has adverse effects on wear process. CaCO3 is considered as highly erosive material in industry. In present study, sand blast type erosion tester is used to investigate influence of particle size in particle impact erosion. The tester accelerates air-borne CaCO3 particles on to a mild steel (DOMEX 355MC) wall material specimen at different impinge angles. Erosion due to different particle sizes was tested under a given velocity (70ms-1) at room temperature. Five different powder samples with different mean diameters of particles within the range of 200μm to 500μm were tested for both 30o and 90o impinge angles. The experiment was conducted for two different exposure times 5 and 35 mins with 30o impact angle. Results displayed a peak of erosion against the particle size for imping angle of 30o whilst 90o impact has a continuous growth in erosion rate within the tested size range. Erosion was significantly high in 30o impinge angle compared to that of the normal impact (90o). In addition, smaller exposure time gave higher erosion rate at 30o impact angle.