Abstract
High chromium white irons (HCCIs) are used extensively throughout the mineral processing industry to handle erosive and corrosive slurries. This study is an investigation of the effect of impact angle and velocity on slurry erosion of HCCI. The tests were carried out using a rotating whirling-arm rig with particle concentration of 1 wt. %. Silica sand which has a nominal size range of 500–710 μm was used as an erodent. The results were obtained for angles of 30 deg, 45 deg, 60 deg, and 90 deg to the exposed surface and velocities of 5, 10, and 15 m/s. The highest erosion resistance of HCCI was at normal impact and the lowest at an angle of 30 deg, irrespective of velocity. The low erosion resistance at an oblique angle is due to large material removal by microcutting from ductile matrix and gross removal of carbides. The effect of velocity, over the studied range from 5 m/s to 15 m/s, on the increase in the erosion rate was minor. The change of impact velocity resulted in changing the slurry erosion mechanisms. At normal incidence, plastic indentation with extruded material of the ductile matrix was the dominant erosion mechanism at low impact velocity (5 m/s). With increasing impact velocity, the material was removed by the indentation of the ductile matrix and to smaller extent of carbide fracture. However, at high impact velocity (15 m/s), gross fracture and cracking of the carbides besides plastic indentation of the ductile matrix were the dominant erosion mechanisms.