IMPACT ANGLE, PARTICLE ENERGY AND MASS-LOSS IN EROSION BY DILUTE SLURRIES

The wear depth in erosion as a function of angular location on cylindr ical specimens, diameter 5 mm, has been measured using suspensions con taining less than 1% by mass of SiC in diesel oil in a slurry-pot eros ion tester. The test variables included particle size and nominal eros ion speed. Wear depth was assessed by recording linear variable differ ential transformer traces of cylinder radius about the circumference o f the cylinders before and after short periods of erosion, chosen to g ive measurable but small wear, to minimize the change in cylinder shap e. Typical erosion times were from 2-20 min. Target materials were Pyr ex glass, 99.8% alumina, 1020 HR steel, API P110 casing steel, OFHC co pper, polymethylmethacrylate, acetal and a cloth-reinforced phenolic. A mathematical model for particle trajectories and impact velocities w as used to estimate the angular location of particle impacts about the cylinder, the corresponding collision efficiencies, impact angles, no rmal and tangential velocities, and the kinetic energies at impact. Ex perimental results and the values predicted by the computer model allo wed comparison of the rate of erosion with the rate of dissipation of kinetic energy of impact with impact angle and angular location about the cylinder. Analysis of wear profiles was made on the basis of the d istinction due to van Riemsdijk and Bitter (1959) between deformation wear (resulting from the normal component of impact velocity) and cutt ing wear (related to the tangential component of impact velocity). Spe cific energies for material removal in erosion, for both deformation a nd cutting wear, are given for all materials. Values are compared with those found for surface grinding and those by Neilson and Gilchrist ( 1968) for gas-solid erosion.