An in-depth analysis of tool wear mechanisms and surface integrity during high-speed hard turning of AISI D2 steel via novel inserts

Over the years, machinists have been exploring the hard part turning of AISI D2 steels. Initially, cylindrical grinding was used for this purpose, but it was later replaced by single-point turning due to its advantages such as high material removal, low cost, and greater flexibility. Conventional inserts are used in single-point turning, but they have been reported to have large radial forces, high notch wear, and poor surface finish. Therefore, multi-radii wiper inserts were designed to overcome these machining issues, but their use was restricted to shallower depths of cut and moderate feed rates because of the thick chips produced by the high entry angle. Prime inserts, on the other hand, were designed with a modest entry angle, making them ideal for evaluating tool wear/life, material removal and surface roughness at greater cutting speeds, depths of cut, and feed rates. It was observed that cutting speed has a significant effect on tool wear/life with a contribution of 55.38% followed by feed rate (13.72%) and depth of cut (11.43%). Cutting speed (84.87%) and feed rate (13.01%) are observed to be the most significant parameters controlling material removed. It was also observed that feed rate has a significant effect on workpiece surface roughness with a contribution of 67.30% followed by depth of cut (20.60%), whereas cutting speed had no significant effect on surface roughness. Moreover, it is found that prime insert outperformed wiper and conventional inserts in terms of tool life/wear and surface roughness.