Performance of multilayer coated carbide tools when turning cast iron

The tool life performance of multilayer hard coatings was evaluated for machining of spheroidal graphite cast iron. TiCN+TiC+Al₂O₃+TiN and TiCN+TiC+Al₂O₃+TiN multilayered coatings with different thick-nesses were fabricated on WC substrates using high temperature chemical vapor deposition (HTCVD). These cutting tools with hard multilayered coating systems were used in the longitudinal turning of spheroidal graphite cast iron under the cutting conditions encountered in the work. To investigate the tool life performance in cutting tools coated by HTCVD, cutting experiments were performed using a CNC turning bench with 3 different cutting tools having multilayered hard coatings and an uncoated insert with square edges, and a type of spheroidal graphite cast irons. The tests were done under various combinations of speed, feed, and depth of cut. Tool life based on flank wear was considered to compare the 3 cutting tools. Tool performance was evaluated with respect to tool wear, surface roughness, and cutting forces at 4 different cutting speeds in the range 125-200 m/min.