Faculty Publications
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Item Influence of deep cryogenic treatment on performance of cemented carbide (WC-Co) inserts during dry end milling of maraging steel(Elsevier Ltd, 2019) Varghese, V.; Ramesh, M.R.; Dupadu, D.Cryogenic treatment has developed as a technique to improve the life of the cutting tool, especially tungsten carbide inserts. The present study investigates the effect of cryogenic treatment of cemented carbide (WC-Co) inserts at the different soaking period of 18 h (CT-18), 24 h (CT-24) and 32 h (CT-32) at a sub-zero temperature of ?196 °C. The soaking period plays a crucial role in improving the wear resistance of the cryogenically treated tools. It is vital to determine the critical soaking period for the cryogenic treatment of cemented carbides. The mechanical and metallurgical characterization of cryogenically treated cemented carbide insert is carried out to understand the changes in the microstructure, grain size, chemical composition, microhardness and electrical conductivity after cryogenic treatment. The end milling experiments on maraging steel under dry environment are carried out using cryogenically treated inserts at different holding time and untreated inserts (UT). The machining performance of treated and untreated inserts are compared with respect to tool wear, surface roughness and cutting forces. The results revealed that cryogenic treatment is effective in resisting tool wear even at high spindle speeds. The cryogenically treated inserts exhibited higher tool life, better surface finish and lower cutting forces during machining at different spindle speeds. The optimum soaking time for cryogenic treatment of WC-Co inserts is found to be 24 h (CT-24) beyond which there is no improvement in microhardness and wear resistance. © 2018Item Characterization and Evaluation of Joint Properties of FSWed AA6061/SiC/FA Hybrid AMCs Using Different Tool Pin Profiles(Springer, 2020) Patil, S.; Narendranath, S.; Dupadu, D.This work reports the characterization of AA6061/SiC/FA hybrid composites joined using friction stir welding (FSW). FSW was conducted by employing various tool pin profiles such as straight cylindrical (SC), tapered conical, straight square (SS) and cylindrical threaded. Microstructure and mechanical characteristics of joints were investigated using these tool pin profiles. Microstructure study of the weld joints was carried out through scanning electron microscopy and electron backscattered diffraction (EBSD) analysis. The results show equiaxed distribution of grains in the nugget zone. EBSD analysis indicates that the average grain size reduces to 3 µm after FSW with the presence of high-angle grain boundaries. Higher joint efficiency (85%) is obtained for joints obtained using SS tool pin compared to their counterparts, and SC tool yields minimum joint efficiency (77%). Overall 8% enhancement of the joint efficiency is achieved using SS tool pin profile. © 2020, The Indian Institute of Metals - IIM.Item Analysis of the Effect of Friction Stir Welding Parameters on Characteristics of AA6061 Composites using Response Surface Methodology(Springer, 2021) Patil, S.; Dupadu, D.; Narendranath, N.Response surface methodology (RSM) is used for mathematical modeling of friction stir welding parameters for joining AA6061 composite material. Characteristics of joints were examined through response characteristics such as ultimate tensile strength (UTS) and microhardness (HV) using RSM. Microstructure examination was carried out using optical microscopy, scanning electron microscopy and electron backscattered diffraction, and results exhibit variation in the grain size diameter. Specifically, lower nugget exhibits fine grains with maximum hardness compared to middle nugget and upper nugget. Analysis of variance (ANOVA) results indicate good match between actual values and predicted values with R2 of 0.91 and 0.96, respectively, for UTS and HV, and better joint efficiency of 90% is obtained. © 2021, The Indian Institute of Metals - IIM.