In this present research, the machinability studies of TiAlN/TiCN, TiCN/TiAlN coated and uncoated inserts were investigated on machining custom 450 alloy. The machining input parameters such as feed rate (f), cutting speed (V) and depth of cut (d) are set using orthogonal array. The machining output parameters such as surface roughness, tool wear and cutting forces were studied for its parametric contribution and it was analyzed using Analysis of Variance (ANOVA). Further, the tool wear obtained was studied using scanning electron microscopic images and energy dispersive spectroscopy analysis was conducted to check the addition of work material elements to the coated tool surface. The results show that, the feed rate is the most contributing factor in deciding resultant forces, surface roughness and tool wear respectively. TiAlN/TiCN coated carbide tool has obtained improved machinability, when compared to TiCN/TiAlN coated carbide and uncoated carbide inserts. To obtain one optimal level for all three responses of three types of tools, multi criteria decision making approach, named utility concept approach is selected. Based on the MCDM analysis, it is found that trial number 4 gives better experimental output of improved surface integrity, lower resultant force and less tool wear for all types of tools.

In the current study, hard turning of AISI H11 tool steel is done using TiAlN coated cutting tool. The workpiece is prepared by three different processing conditions (Solution treated, Heat treated, Cryogenic treated). The machining performance are studied by the input parameters; cutting speed (60, 90, 120 m/min) and feed rate (0.06, 0.12, 0.18 mm/rev) with a constant depth of cut of 0.5mm using Taguchi’s L9 design. The responses like, surface quality, wear on the tool, and forces generated for all three specimens are studied. The hardness of all three components is measured using Vicker’s micro-hardness tester. The experimental results proved that feed rate is the most influential parameter in deciding, surface roughness, cutting force and tool wear. The utility concept approach is applied and found, solution treated sample with 120 m/min of cutting speed and 0.06 mm/rev of feed rate produces optimal results in all three response criterion.