Investigation of the Wear Behavior of Abrasive Grits in a Dry Machining Inconel 718 Narrow-Deep-Groove with a Single-Layer Cubic Boron Nitride Grinding Wheel

Abstract

The wear behavior of a single-layer electroplated cubic boron nitride (cBN) grinding wheel was investigated in creep feed profile grinding Inconel 718 narrow-deep-groove with a width of 2 mm. In this paper, the protrusion height of cBN grits on the side edge of the grinding wheel was measured by three-dimensional optical profiler, and a scanning electron microscope was used to detect the topography of worn cBN grit and the nickel bonding layer. The investigation results indicated that the steady wear stage of the grinding wheel shared more than 84.6% of the wheel lifespan, and the machining precision of the grinding wheel was kept at a high level. The fracture mode of the cBN grit was proven to be cleavage. The source of the cleavage cracks was observed on the surface of wear flat or the side surface of the cBN grit. The holding strength of cBN grit could be weakened due to the joint surface breakage, the displacement of grit, or the cracks of the nickel bonding layer. The transition layer was contributed to the decrease of the bonding strength. Severe macro fractures and the concentration of pulled out grits were observed on the transition edge and the inner area of the side edge, separately. This study provides a deep understanding of the wear mechanism of a single-layer electroplated cBN grinding wheel.