Experimental Investigation and Surface roughness Analysis on Hard turning of AISI D2 Steel using Coated Carbide Insert

The machining of hard turning is carrying out on hardened steel in the range of 45 to 68 Rockwell hardness. It is substitute to traditional grinding process is a flexible, productive and successful machining process for hardened metals. Hence mainly used in various uses such as dies, moulds, tools, gears, cams, shafts, axles, bearings and forgings. The machining of hardened steel using superior tool materials such as coated carbide inserts, mixed ceramic inserts and cubic boron carbide nitride(CBN) have higher merits than traditional grinding such as high material removal rate, can produce good surface finish, reduced processing costs, ability to machine narrow walled sections and minimum environmental problems without using cutting fluid. Although the process is accomplish with small depth of cut and feed rates, evaluate to minimizing the machining time as high as 60% in hard turning process.In this paper, the machining of AISI D2 steel workpiece having 66 HRC hardness is carried out using coated carbide insert. The microstructure shows rolled grains of the steel along the direction of the material. The microstructure shows fine grains of cementite with the grain boundary chromium and other alloys and the presence of carbide, which increases strength and wearresistant. This paper discusses the importance of hard turning of AISI D2 steel. Investigations were carried out on conventional lathe using the prefixed cutting conditions. The graph shows the feed rate is the main impact with increasing feed rate, but reduces with larger cutting speed and rapidly increasing depth of cut. The responses studied in the investigation of surface roughness are studied in the investigation of surface roughness parameters (Ra,Rt and Rz) on responses are studied and presented in detail.