EXPERIMENTAL INVESTIGATIONS INTO MACHINING OF AISI 316 STAINLESS STEEL FOR SURFACE ROUGHNESS AND MICROHARDNESS BENEATH MACHINED SURFACE UNDER DRY ENVIRONMENT

Now a day’s manufacturing system is oriented towards higher production rate, quality, and reduced cost. Surface roughness is an index for determining the quality of machined products and is influenced by the cutting parameters. Surface finish is an important criterion in industry for product quality, which ultimately depends on various process parameter like cutting speed, feed, depth of cut, and so on. To get the better surface finish, proper selection of process parameters and their values are important. The austenitic stainless steel AISI 316 is hard to machine and has problem of surface finish and tool wear. In this work, by performing turning operation under dry environment, with parameters in the range of cutting speed (Vc) 120-170-270 m/min, feed(f) 0.15-0.25-0.35 mm/rev, and depth of cut(d) 0.6-1.2-1.8 mm. The optimal machining condition achieved was Speed = 170 m/min, feed = 0.15 mm/rev, and depth of cut = 0.6 mm for a minimum value of surface roughness Ra= 0.87 µm. Also, from ANOVA, feed was found to be most significant factor for surface roughness. In addition, regression model for surface roughness has been developed. The model predictions have found to agree with the experimental results. At the same time, study on microhardness beneath machined surface was done. It was found that for higher feed and higher depth of cut, microhardness variation increased, indicating that feed and then depth of cut are significant factors for microhardness variation.