Effects of cryogenic treatment on the performance of coated tungsten carbide inserts during milling of EN24 steel

Cryogenic treatment is one of the innovative techniques to improve the performance of cutting tools. The present study investigated the effects of cryogenic treatment on the performance of cutting tools, while machining (CNC milling) EN24 steel. The TiCN-coated tungsten carbide inserts (APKT09) were procured and exposed to shallow cryogenic treatment at −80 °C for 6 h and deep cryogenic treatment at −196 °C for 24 h independently. The experiments were designed using Taguchi’s L9 orthogonal array. Milling tests were performed by considering three cutting speeds (1900, 2200, and 2500 rpm), three feed rates (350, 440, and 530 mm/min), and three depths of cut (0.40, 0.65, and 0.90 mm) under dry cutting conditions. The machining performance of cryogenically treated and untreated inserts was evaluated in regard to the flank wear of the inserts and the surface roughness of the machined workpiece. Cryogenically treated inserts exhibited reduced flank wear and surface roughness than untreated inserts. The best flank wear and surface roughness performance were attained with the deep cryogenically treated inserts. Moreover, an improvement in the microhardness of the cryo-treated inserts was observed.