A study of carbide removal mechanisms during quartz abrasion: II: Effect of abrasive particle shape

The effect of abrasive particle shape on fracture and pit formation in carbides during low stress abrasion of high chromium white cast irons by AFS 50–70 Ottawa quartz test sand is described in this paper. Abrasion tests were performed using a rubber wheel abrasion test apparatus and the abraded surfaces were examined in the scanning electron microscope. The shapes of the fresh and used abrasive particles were analyzed using the scanning electron microscope. Scratch tests were performed in situ in the scanning electron microscope using individual grains of fresh semiangular quartz particles and fractured angular quartz particles as scratch tools. Hertzian elastic theory was applied to gain a semiquantitative understanding of the effect of the radius of curvature of the abrasive particle tip on carbide fracture.The results of this study indicate that fracture of the carbides is initiated by the action of an extremely small portion of the abrasive particles which fracture during abrasion and therefore become very sharp and angular. Further crack extension and subsequent pit formation in carbides can be caused by the action of fresh rounded abrasive particles.