Experimental Study & Modeling of Surface Roughness in Turning of Hardened AISI 4340 Steel Using Coated Carbide Inserted

Turning of hardened steels using a single point cutting tool has replaced the cylindrical grinding now as itoffers attractive benefits in terms of lower equipment costs, shorter set up time, fewer process setups,higher material removal rate, better surface quality and elimination of cutting fluids compared to cylindricalgrinding. In order to obtain desired surface quality by machining, proper machining parameters selection isessential. This can be achieved by improving quality and productivity in metal cutting industries. Thepresent study is to investigate the effect of machining parameters such as cutting speed, feed and depth ofcut on surface roughness during dry turning of hardened AISI 4340 steel with CVD(TiN+TiCN+Al2O3+ZrCN) multilayer coated carbide inserts. A full factorial design of experiment isselected for experimental planning and the analysis of variance (ANOVA) has been employed to analyzethe significant machining parameters on surface roughness during turning. The results showed that feed(60.85%) is the most influencing parameter followed by cutting speed (24.6%) at 95% confidence level.And the two-level interactions of feed-cutting speed (F*V), depth of cut-feed (D*F) and depth of cutcuttingspeed (D*V) are found the significant effects on surface roughness in this turning process.Moreover, the relationship between the machining parameters and performance measure i.e. surfaceroughness has been modeled using multiple regression analysis.