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S. Gangopadhyay

Bio: S. Gangopadhyay is an academic researcher from National Institute of Technology, Rourkela. The author has contributed to research in topics: Machining & Surface roughness. The author has an hindex of 24, co-authored 47 publications receiving 1587 citations. Previous affiliations of S. Gangopadhyay include Indian Institute of Technology Kharagpur.

Papers published on a yearly basis

Papers
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Journal ArticleDOI
TL;DR: In this article, the state-of-the-art on various surface integrity characteristics during machining of nickel-based super alloys are presented, including surface roughness, defects (surface cavities, metal debris, plucking, smeared material, redeposited material, cracked carbide particles, feed marks, grooves and laps).
Abstract: Nickel-based super alloys are gaining more significance, now-a-days, with extensive applications in aerospace, marine, nuclear reactor and chemical industries. Several characteristics including superior mechanical and chemical properties at elevated temperature, high toughness and ductility, high melting point, excellent resistance to corrosion, thermal shocks, thermal fatigue and erosion are primarily responsible for wide domain of application. Nevertheless, machined surface integrity of nickel-based super alloys is a critical aspect which influences functional performance including fatigue life of the component. This review paper presents state-of-the-art on various surface integrity characteristics during machining of nickel-based super alloys. Influence of various cutting parameters, cutting environment, coating, wear and edge geometry of cutting tools on different features of surface integrity has been critically explained. These characteristics encompass surface roughness, defects (surface cavities, metal debris, plucking, smeared material, redeposited material, cracked carbide particles, feed marks, grooves and laps), metallurgical aspects in the form of surface and sub-surface microstructure phase transformation, dynamic recrystallisation and grain refinement and mechanical characteristics such as work hardening and residual stress. Microstructural modification of deformed layer, profile of residual stresses and their influence on fatigue durability have been given significant emphasis. Future research endeavour might focus on development of new grades, advanced processing techniques of the same to ensure their superior stability of microstructure and thermo-mechanical properties along with advanced manufacturing processes like additive manufacturing to achieve highest level of fatigue durability of safety critical components while maintaining acceptable surface integrity and productivity.

403 citations

Journal ArticleDOI
TL;DR: In this article, a nickel-based super alloy was machined under completely dry environment using a commercially available multilayer (TiN/TiAlN) coated tool obtained using physical vapour deposition (PVD).

97 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive mathematical model based on Response Surface Methodology (RSM) was developed for correlating the interactive and higher-order influences of major machining parameters i.e. peak current and pulse-on-duration on different aspects of surface integrity of M2 Die Steel machined through EDM.

93 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the influence of various EDM process parameters like pulse current (Ip), pulse-on time (T on ), tool work time ( T w ), and tool lift time (t up ) on various aspects of surface integrity like white layer thickness (WLT), surface crack density (SCD), surface roughness (SR), and dimensional accuracy, characterized by over cut (OC).

91 citations

Journal ArticleDOI
TL;DR: In this article, the influence of different EDM process variable peak current (I p ), duty factor (T au), and pulse-on duration (T on) on various performance characteristics such as material removal rate (MRR), surface roughness (SR), radial overcut (ROC), and surface crack density (SCD).
Abstract: Recently, electro-discharge machining (EDM) has become one of the preferred machining techniques for Ni-based super alloys. Although extensive research has been reported on EDM characteristics of Inconel 718, not much information is available on Inconel 825. Owing to the excellent resistance to corrosion, Inconel 825 finds particular application in highly corrosive environment. Therefore, the current investigation aims at studying the influence of different EDM process variable peak current (I p ), duty factor (T au), and pulse-on duration (T on) on various performance characteristics such as material removal rate (MRR), surface roughness (SR), radial overcut (ROC), and surface crack density (SCD). Experiments were designed and carried out using L9 orthogonal array. The most influencing factor for responses MRR, SR, and ROC was found to be I p with percentage contribution of 51.22%, 81.08%, and 54.78%, respectively, while it was T on for SCD with 39.54% contribution. Since EDM involves multiple performanc...

86 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the state-of-the-art on various surface integrity characteristics during machining of nickel-based super alloys are presented, including surface roughness, defects (surface cavities, metal debris, plucking, smeared material, redeposited material, cracked carbide particles, feed marks, grooves and laps).
Abstract: Nickel-based super alloys are gaining more significance, now-a-days, with extensive applications in aerospace, marine, nuclear reactor and chemical industries. Several characteristics including superior mechanical and chemical properties at elevated temperature, high toughness and ductility, high melting point, excellent resistance to corrosion, thermal shocks, thermal fatigue and erosion are primarily responsible for wide domain of application. Nevertheless, machined surface integrity of nickel-based super alloys is a critical aspect which influences functional performance including fatigue life of the component. This review paper presents state-of-the-art on various surface integrity characteristics during machining of nickel-based super alloys. Influence of various cutting parameters, cutting environment, coating, wear and edge geometry of cutting tools on different features of surface integrity has been critically explained. These characteristics encompass surface roughness, defects (surface cavities, metal debris, plucking, smeared material, redeposited material, cracked carbide particles, feed marks, grooves and laps), metallurgical aspects in the form of surface and sub-surface microstructure phase transformation, dynamic recrystallisation and grain refinement and mechanical characteristics such as work hardening and residual stress. Microstructural modification of deformed layer, profile of residual stresses and their influence on fatigue durability have been given significant emphasis. Future research endeavour might focus on development of new grades, advanced processing techniques of the same to ensure their superior stability of microstructure and thermo-mechanical properties along with advanced manufacturing processes like additive manufacturing to achieve highest level of fatigue durability of safety critical components while maintaining acceptable surface integrity and productivity.

403 citations

01 Jan 2016

301 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive analysis of literature pertaining to ecological trends in machining processes of difficult-to-cut materials (e.g. hard steels, Ti-based alloys, Ni based alloys) has been performed.

260 citations

Journal ArticleDOI
TL;DR: In this paper, the impact of different types of dielectrics on the performance of micro-EDM machining was investigated using scanning electron microscope (SEM) micrographs and optical photographs.
Abstract: In microelectrodischarge machining (micro-EDM), dielectric plays an important role during machining operation. The machining characteristics are greatly influenced by the nature of dielectric used during micro-EDM machining. Present paper addresses the issues of micro-EDM utilizing different types of dielectrics such as kerosene, deionized water, boron carbide (B4C) powder suspended kerosene, and deionized water to explore the influence of these dielectrics on the performance criteria such as material removal rate (MRR), tool wear rate (TWR), overcut, diameteral variance at entry and exit hole and surface integrity during machining of titanium alloy (Ti-6Al-4V). The experimental results revealed that MRR and TWR are higher using deionized water than kerosene. Also, when suspended particles, i.e., boron carbide-mixed dielectrics are used, MRR is found to increase with deionized water, but TWR decreases with kerosene dielectric. Further analysis is carried out with the help of scanning electron microscope (SEM) micrographs, and it is found that the thickness of white layer is less on machined surface when deionized water is used as compared to kerosene. Also, a comparative study of machining time has been carried out for the four types of dielectrics at different machining parametric settings. Furthermore, the investigation on the machined surface integrity and wear on microtool tip have also been done in each type of the dielectrics with the help of SEM micrographs and optical photographs. Hence micro-EDM machining on Ti-6Al-4V work material with B4C-mixed dielectrics is performed in the investigation and reported the performance criteria of the process. It can be concluded from the research investigation that there is a great influence of mixing of boron carbide additive in deionized water dielectrics for enhancing machining performance characteristics in micro-EDM during microhole generation on Ti-6Al-4V alloy.

213 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a systematic, critical, and comprehensive review of all aspects of dry machining including the sustainability aspects of machining, especially focusing on three research objectives.

195 citations