Effect of Cooling/Lubrication Modes on Tool Wear Mechanisms in Turning Pure Iron Material

The suitable cooling/lubrication modes are the key technology to reduce the friction coefficient between the interface of chip-tool, to improve tool lifetime to reduce cutting force and temperature. The experiments of turning pure iron material were conducted with different cutting speeds under four cooling/lubrication modes, i.e. dry cutting, water-based coolant, minimum quantity lubrication (MQL) and brushing rapeseed oil, to investigate the effects of cooling/lubrication modes on tool wear mechanisms. The results show that the main tool wear mode was flank wear and there were two severe notches wear on major cutting edge and minor cutting edge, respectively. The workpiece material was adhered on rake face to form built-up edge. It had the longest tool lifetime under MQL and the least under water-based coolant.Diffusion wear, adhering wear and oxidation wear were the main wear mechanisms for the cutting tools in turning pure iron. The distinct difference of cutting force, the average friction coefficient between the interface of chip and rake face and the microhardness of machined workpiece surface under four cooling/lubrication modes were the primary reasons, which resulted in different tool lifetime in turning pure iron material.