International Journal of Innovation and Applied Studies ISSN 2028-9324 Vol. 2 No. 4 Apr. 2013, pp. 445-453 © 2013 Innovative Space of Scientific Research Journals http://www.issr-journals.org/ijias/ Corresponding Author: Sudhansu Ranjan Das (das.sudhansu83@gmail.com) 445 Effect of Machining Parameters on Surface Roughness in Machining of Hardened AISI 4340 Steel Using Coated Carbide Inserts Sudhansu Ranjan Das 1 , Amaresh Kumar 2 , and Debabrata Dhupal 3 1 Research Scholar, Department of Production and Industrial Engineering, National Institute of Technology, Jamshedpur, Jharkhand, India 2 Associate Professor, Department of Production and Industrial Engineering, National Institute of Technology, Jamshedpur, Jharkhand, India 3 Professor, Department of Production Engineering, Veer Surendra Sai University of Technology, Burla, Odisha, India Copyright © 2013 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT: Turning of hardened steels using a single point cutting tool has replaced the cylindrical grinding now as it offers 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 cylindrical grinding. In order to obtain desired surface quality by machining, proper machining parameters selection is essential. This can be achieved by improving quality and productivity in metal cutting industries. The present study is to investigate the effect of machining parameters such as cutting speed, feed and depth of cut on surface roughness during dry turning of hardened AISI 4340 steel with CVD (TiN+TiCN+Al 2 O 3 +ZrCN) multilayer coated carbide inserts. A full factorial design of experiment is selected for experimental planning and the analysis of variance (ANOVA) has been employed to analyze the 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 cut-cutting speed (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. surface roughness has been modeled using multiple regression analysis. KEYWORDS: AISI 4340 steel, Surface Roughness, Factorial Design, ANOVA. 1 INTRODUCTION The achivement of high quality, in terms of workpiece dimensional accuracy, surface finish, high production rate, less wear on the cutting tools, economy of machining in terms of cost saving and increase the performance of the product with reduced enviornmental impact are the main and effective challenges of modern metal cutting and machining industries [1]. Traditionally, hardened steels are machined by grinding processdue to their high strength and wear resistance properties but grinding operations are time consuming and limited to the range of geometries to be produced. In recent years, machining the hardened steel in turning which uses a single point cutting tool has replaced grinding to some extent for such application. This leads to reduced the number of setup changes, product cost and ideal time without compromising on surface quality to maintain the competiveness [2,3]. The improve technological process, proper tool selection, determination of optimum machining parameters (cutting speed, feed, depth of cut, etc.) or tool geometry (nose radius, rake angle, edge geometry, etc.) are necessary inorder to obtain the desired surface finish comparable to grinding [4,5,6].