Study of material separation mechanisms under cryogenic cooling

Abstract

The combination of highly heat-conducting cubic boron nitride (cBN) grains in a bronze-bonded grinding wheel with the cryogenic temperatures of a gaseous carbon dioxide cooling has the potential to greatly reduce the thermal load during the grinding process. This decreases the risk of thermal damage or heat-induced property changes in the workpiece. In this study, the influence of this combination on the material separation while grinding 20MnCrS5 steel is investigated using a quick-stop device, compared to a conventional oil-based cooling. The contact zone analysis shows primarily grooving grain tracks while grinding with oil cooling. However, under the influence of cryogenic cooling, mostly grain tracks from plowing grains were found in the contact area as a result of the increased friction between the grains and the workpiece material. This shows that material separation with cryogenic cooling is more efficient compared to the oil-cooled process.