Retificação plana do aço SAE 52100 com fluido de corte contendo grafeno aplicado pela técnica MQL

Abstract

Due to environmental, social and economic issues, research has been developed to find alternatives to conventional technique (where the cutting fluid is used at high flow rates), mainly to reduce the volume of cutting fluid without harming the grinding process and compromising the quality of the workpiece. Among these alternatives, the addition of solid particles to the cutting fluid combined with the minimum quantity of lubricant (MQL), especially as graphene platelets, for example, has been shown to be promising in grinding processes. The presence of these particles has contributed to the improvement of fluid properties, for example, the thermal conductivity was raised, potentiating its cooling effect and being an option to increase the efficiency of the MQL technique. In this context, the current work aims to verify the efficiency of the multilayer graphene platelets dispersed in cutting fluid in peripheral surface grinding of SAE 52100 steel with aluminum oxide grinding wheel under different cutting conditions. In addition to the different cooling-lubrication conditions tested (conventional, MQL (without graphene) and MQL + Graphene), grit size of grinding wheel (mesh 46 and 60), radial depth of cut (10 μm and 30 μm) and workpiece speed (3 m/min and 7 m/min) were varied. The output parameters monitored were: surface roughness parameters (Ra and Rz) and microhardness of the workpiece, as well as power grinding and texture/quality of the ground surfaces. The results showed that the presence of graphene generated the lowest values of roughness, the least variation in microhardness as well as the lowest power consumed in the process. This condition was also responsible for the best quality of the machined surfaces. Also, roughness and grinding power increased with the radial depth of cut and workpiece speed, whereas the highest drop in microhardness below the machined surface was observed after machining with the lowest workpiece speed of 3 m/min and radial depth of cut of 30 μm.