Steel subsurface damage on plunge cylindrical grinding with sol-gel aluminum oxide grinding wheels

Highlighted in many engineering applications, such as bearing and crankshaft grinding, cylindrical circumferential plunge grinding is a manufacturing process that encompasses multiple stages (roughing, finishing and spark-out) in a series of overlapping steps. Although this is especially a critical process when grinding with aluminum oxide abrasive grits, only a little information of the subsurface damage is available when applying microcrystalline aluminum oxide grits. In order to evaluate the influence of the microcrystalline Al2O3 grits content in conventional grinding wheels on the ground subsurface, grinding experiments were performed. The microcrystalline aluminum oxide abrasive grit content was varied from 15 to 45%. The morphological characteristics of the grinding wheels were analyzed via X-ray tomography. A single-step specific material removal rate (roughing condition) was selected to induce microstructural modifications on the workpiece subsurface. The grinding force was monitored, and its components were determined. The X-ray tomography revealed that with a variation of the microcrystalline aluminum oxide content, the binder proportion that classified the used and evaluated grinding wheels with the same hardness does not present the same binder content. This is a piece of information normally not present in the description of the wheels by the manufacturer and is helpful to explain behaviors on the force and affected layer, not possible only with the information of grit content and hardness. Investigating the present layers on the modified microstructure suggests the governing phenomena during cutting, and a deepening of the studies with X-ray tomography helps to explain phenomena that were not explainable before.