Performance of synthetic and mineral soluble oil when turning AISI 8640 steel

The present work shows a comparative study of the application of synthetic and semisynthetic, mineral soluble oil (at concentrations of 3 and 10 percent) as well as dry cut when turning AISI 8640 steel bars with triple coated (TiC,Al2O3,TiN) P35 grade of cemented carbide tools. Tool lives, cutting forces, cutting temperatures and surface roughness were considered to evaluate the cutting fluids. Generally, the semi-synthetic gave longer tool life based on flank wear parameter VB. The surface roughness was not sensitive to the lubrication quality, if wear effects are not considered. Mean tool-chip interface temperature was lower with the synthetic fluid, followed by the semisynthetic, mineral soluble oils and dry cutting, respectively. The inverse of this order was true for the cutting forces.