Study on polishing mechanism of cemented carbide by means of blast polishing

3^rd Report: Influence of water content in polishing media on polishing mechanism

Abstract

Our previous study showed that under constant kinetic energy of polishing media, higher polishing rate is achieved in media with the lowest water content, while the saturated surface roughness increases in such media. To verify this unique polishing phenomenon, the influence of water content in polishing media on the polishing mechanism was investigated in the present study. The results revealed that the surface hardness of the cemented carbide substrate increases with higher injection speed of the media. This indicates that, although the abrasive grain surface removal force is high under higher injection speed, it becomes less likely to bite deep into the substrate surface due to the greater hardness increase of the substrate, which is induced by the water content in the polishing media. In addition, the effect of water content on the elasticity of the polishing media was evaluated and how the elasticity affects the impact force during the collision was examined. The results indicated that the optimum combination of water content and injection speed becomes an essential principle for the moderate blast polishing process.