Metal adhesion issues in dry grinding: The role of active fillers

Abstract

The dry grinding of metals is a common machining operation. The main issue with such techniques is metal adhesion on the abrasive tool, which decreases the material removal rate. In this work, the effect of active filler metal loading with materials such as cryolite and KBF4, which are present in the resin of commercial abrasive belts, was studied. Grinding belt experiments and friction tests were performed with carbon and stainless steel and with belts containing zirconia-reinforced-alumina grains, as well as active fillers. The tests were followed by SEM-EDX, TEM or XPS characterizations of the belts and ceramic pieces. Different behaviors were observed for different types of metal, as stainless steel is more sensitive to loading than carbon steel, and because active fillers have a stronger positive effect against metal adhesion, such as in the case of stainless steel. Then, a fluorine based layer, derived from the active fillers, was found at the interface between the grain and the metallic transfer. This layer likely limits the adhesion of metal on the grain and decreases the contact friction, as well as the specific grinding energy (SGE). The corrosion of alumina in the abrasive grains by active fillers was also observed near contact temperatures. Finally, the results are discussed to gain a better understanding of different active filler action mechanisms taking place during the steel grinding process.