Title: Some investigations in hard turning of AISI 4340 alloy steel in different cutting environments by CBN insert

Authors: Deepak M. Naigade; Deepakkumar H. Patil; Mudigonda Sadaiah

Addresses: Department of Mechanical Engineering, Dr. Babasaheb Ambedkar Technological University, Vidyavihar, Lonere Tal: Mangaon Dist: Raigad, Maharashtra, 402103, India ' Department of Mechanical Engineering, Dr. Babasaheb Ambedkar Technological University, Vidyavihar, Lonere Tal: Mangaon Dist: Raigad, Maharashtra, 402103, India ' Department of Mechanical Engineering, Dr. Babasaheb Ambedkar Technological University, Vidyavihar, Lonere Tal: Mangaon Dist: Raigad, Maharashtra, 402103, India

Abstract: Generally, hard turning requires large quantity of coolants and lubricants. In the present study, minimal quantity lubrication (MQL) is used for cooling in turning of hardened alloy steel AISI 4340 (45 HRC) with CBN insert of MT KB 5625 grade. The effect of MQL environment on surface roughness, cutting force components is studied and compared with dry and wet environments. The experiments were conducted using Taguchi L₁₈ (2¹ × 3⁷) mixed orthogonal array. Analysis of variance (ANOVA) of the experimental results shows that depths of cut and cutting environment have statistically 95% significant effect on the cutting force components. The cutting environment is statistically significant at more than 95% confidence level on the surface roughness value (Ra). The surface finish, Ra value for dry and wet turning were 0.49 µm and 0.47 µm, respectively and whereas in MQL turning it is 0.36 µm. It was also observed that tightly coiled chips were formed and can be handled easily during MQL. The study indicates that MQL technique can be environment friendly and form a viable alternative to conventional wet turning.

Keywords: hard turning; minimal quantity lubrication; MQL; Taguchi methods; analysis of variance; ANOVA; design of experiments; DOE; AISI 4340 alloy steel; CBN inserts; surface roughness; surface quality; cutting force.

DOI: 10.1504/IJMMM.2013.055736

International Journal of Machining and Machinability of Materials, 2013 Vol.14 No.2, pp.165 - 193

Received: 06 Feb 2012
Accepted: 06 Dec 2012
Published online: 26 Dec 2013 *

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