Investigation on notch wear mechanism in finish turning pure iron material with uncoated carbide tools under different cooling/lubrication conditions

Abstract

Notch wear is the main failure mode in finish turning pure iron material, which determines the tool life and has an important effect on machined workpiece surface quality. In this paper, in order to reduce notch wear in finish turning pure iron material, the evolutions and mechanisms of notch wear on cutting tool edge are studied with different cutting parameters and four kinds of cooling/lubrication conditions, such as wet cutting, dry cutting, hand operation to brush rapeseed oil on unmachined workpiece surface, and minimum quantity lubrication (MQL). The results show that two notch wear formations are observed at the major cutting edge and the minor cutting edge on flank face as well as two obvious notch wears on rake face. The main wear mechanisms of notch wear are the seizure/pullout, diffusion wear, and oxidation wear. Cooling/lubrication conditions have an important effect on major and minor notch wear. The major and minor notch wear under wet cutting with different cutting speeds have the largest wear rates, following under dry cutting and rapeseed oil lubrication conditions. MQL condition is suitable for the finish turning of pure iron materials. Therefore, in order to decrease notch wear, in finish turning pure iron material, tool cooling must be minimized and tool lubrication must be favored.