Fracture of Abrasive Grain in Grinding

Abstract

The fracture strength of single grits of alumina abrasive grain, as observed while cutting mild steel, was measured as a function of the grain depth of cut, the tangential force during cutting, and the number of cuts made before fracture. A one-component force dynamometer with a natural frequency in excess of 20,000 cps was used to measure the variation in tangential force during a single cutting event which was typically 100 to 200 μsec in duration. Data are presented showing the distribution of tangential force as a function of depth of cut and the cumulative distributions of fracture stress and the number of cuts to failure. It is concluded that the failure mechanism during the first few cuts is different from the mechanisms which cause long-term failure. The definition of failure of grain over a long period must include progressive fracture and wear.