Erosion wear of ceramic and cemented carbide nozzles in dry sand blasting process

摘要

In the dry sand blasting process, the nozzle is the most critical component and is worn by repeated impact of abrasive particles. Erosion wear of the nozzle is influenced by various factors such as its mechanical properties and microstructure. In the present study, monolithic B₄C, Al₂O₃/(W,Ti)C, WC/TiC/Co, and WC/Co composites, providing a reasonably wide range of mechanical properties and microstructure, were produced for use as nozzle materials. The erosion wear caused by abrasive particle impact was compared with that due to an abrasive air jet, by determining the cumulative mass loss and erosion rates of nozzles made from these materials. The effects of nozzle material mechanical properties and microstructure on erosion wear were investigated. Results showed that the hardness of the nozzle material plays an important role with respect to erosion wear in dry sand blasting. With their high hardness, the monolithic B₄C nozzles exhibited lower erosion rates, while WC/TiC/Co and WC/Co cemented carbide nozzles with relatively low hardness showed higher erosion rates under the same test conditions. Analysis of eroded bore surfaces of the nozzles demonstrated that monolithic B₄C nozzles exhibited a brittle fracture induced removal process, while WC/TiC/Co and WC/Co nozzles mainly showed a ploughing mode of material removal. Both material removal modes seemed to occur in the Al₂O₃/(W,Ti)C ceramic nozzles.