Faculty Publications

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Author: search.filters.author.Badiger, R.I.

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    Optimization of Parameters Influencing Tensile Strength of Inconel-625 Welded Joints Developed Through Microwave Hybrid Heating
    (Elsevier Ltd, 2018) Badiger, R.I.; Narendranath, S.; Srinath, M.S.
    Processing of bulk metals through microwave energy in recent years is finding widespread applications and is being prominently accepted by the manufacturing industries. Present work, investigates the effect of process parameters on the tensile strength of Inconel-625welded joints produced through microwave hybrid heating using design of experiments. Experiments were carried out by using Taguchi's L16 factorial design of experiment method. Input parameters chosen were separator type; susceptor type and filler powder size. The output response chosen was ultimate tensile strength. Optimization of the process parameters is done through Taguchi method and percentage influence of each process parameter on the strength of weld is determined using ANOVA method. Combination of parameters with graphite separator, SiCsusceptor and finer filler powder yields optimum result. © 2017 Elsevier Ltd.
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    An investigation on effects of wire-EDT machining parameters on surface roughness of INCONEL 718
    (Elsevier Ltd, 2019) Naik, G.M.; Anjan, B.N.; Badiger, R.I.; Bellubbi, S.; Mishra, D.
    This paper studied the effects of machining parameters on surface roughness of wire EDT of INCONEL 718 super alloy. The investigated machining parameters were rotational speed, pulse-on time, pulse-off time, servo voltage, wire feed rate and flushing pressure. Analysis of variance (ANOVA) technique was used to find out the most significant parameters affecting the surface roughness. Results from ANOVA show that pulse-on time is significant variables to surface roughness of wire-EDT INCONEL 718 alloy. The surface roughness of the test specimen increased as these variables increased. Lastly, regression model was developed using a regression method to formulate the machining parameters to the surface roughness. The developed model was validated with an optimal setting parameters and the maximum prediction error of the model was less than 8%. © 2019 Elsevier Ltd.
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    Effect of input power and interfacial powder size on microwave joining of different materials: A review
    (Elsevier Ltd, 2021) Kamble, D.L.; Sahu, R.; Narendranath, S.; Badiger, R.I.
    The use of microwave energy for processing of different materials is gaining significant attention in today's manufacturing industries. The microwave energy found to be applied in sintering, cladding, brazing, joining, casting and drilling of variety of materials. This paper is focused on the detailed review of the research works carried out on the effect of input power of microwave source and interfacial powder size on joint characteristics of different materials. It has been reported that majority of the isotropic to orthotropic materials can be joined using microwave heating source. The characteristics of the joints produced through microwave energy were studied by various researchers using mechano-metallurgical characterization techniques like tensile and hardness tests technique, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The characterization results found in different works are presented in the paper. © 2021 Elsevier Ltd. All rights reserved.
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    Saltwater corrosion behaviour of equal channel angular pressed AZ80/91 Mg alloys
    (Elsevier Ltd, 2021) Hebbale, A.M.; Naik, G.M.; Badiger, R.I.; Bellubbi, S.; Patil, S.; Narendranath, S.
    In this study, AZ80/91 Mg alloys were used to comprehend the electrochemical corrosion behaviour of coarse-grained and fine-grained Mg alloys in different concentration of NaCl solution as well as in the marine environment. The inadequate studies of the corrosion response of ECAPed AZ80 and AZ91 Mg alloy in a different environment were noticed. Accordingly, the current research presents and compares the corrosion behaviour of AZ80/91 Mg alloys in 2.5 wt% NaCl, 3.5 wt% NaCl solution and Natural Sea Water. Influence of corrosion media on coarse and fine-grained AZ80/91 Mg alloys was discussed in the results and discussion section. Corrosion attack of AZ80/91 Mg alloys under the above environment, increased with increase in chloride ion concentration and decreased with the ECAP passes. © 2021 Elsevier Ltd. All rights reserved.
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    Joining of Inconel-625 alloy through microwave hybrid heating and its characterization
    (Elsevier Ltd, 2015) Badiger, R.I.; Narendranath, S.; Srinath, M.S.
    Joining of bulk metals using microwave energy is being explored as a new processing method in the era of high technology applications. The present work investigates the results of on-going project in which joining of Inconel-625 alloy has been effectively carried out through microwave hybrid heating. Characterization of the microwave developed joints is done through SEM, XRD, UTM and Vicker's microhardness tester. The microstructural analysis through scanning electron microscope exhibits a fully fused weld interface free from interfacial cracks. XRD study reveals the formation of carbides of Ni, Cr and Mo in the joint interface. The average Vicker's microhardness in the joint region observed was 360 ± 20 Hv. Assessment of tensile strength shows an ultimate tensile strength of 328 MPa with 9.04% elongation. Further the fractured joints are subjected to fractography study which possibly reveals a mixed mode fracture. © 2015 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.
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    Microstructure and mechanical properties of Inconel-625 welded joint developed through microwave hybrid heating
    (SAGE Publications Ltd info@sagepub.co.uk, 2018) Badiger, R.I.; Narendranath, S.; Srinath, M.S.
    Application of microwave energy for processing of bulk metals is effectively utilized to join Inconel-625 plates through hybrid heating technique using Inconel-625 powder as an interface filler material. Post welding characterization of microwave developed joints through X-ray diffraction shows the development of carbides of niobium and chromium as well as intermetallic phases along with the primary ?-phase face-centered cubic matrix. Microstructural examination reveals the formation of Laves phase along the grain boundaries in the fusion zone. Microwave-induced joints exhibit average microhardness of 245 ± 20 HV and 0.7% porosity in the fusion zone. Average ultimate tensile strength and flexural strength of the developed joints were estimated at 375 and 377 MPa respectively. Average impact toughness of microwave-induced joints is observed to be 18 J. © IMechE 2017.
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    Optimization of Process Parameters by Taguchi Grey Relational Analysis in Joining Inconel-625 Through Microwave Hybrid Heating
    (Springer New York LLC barbara.b.bertram@gsk.com, 2019) Badiger, R.I.; Narendranath, S.; Srinath, M.S.
    The quality of welded joints developed using microwave hybrid heating (MHH) technique is largely influenced by properties of the constituents employed in the process. This article investigates the influence of process parameters on tensile strength and flexural strength of Inconel-625 plates welded through MHH. Experiments were planned according to Taguchi L 16 orthogonal array by considering three factors: separator, susceptor and filler powder particle size. Ultimate tensile strength and flexural strength of the specimens welded at 600 and 900 W were chosen as response characteristics. Application of Taguchi-based GRA has been effectively used to optimize multi-performance characteristics of the process. ANOVA results indicate that size of interface filler powder is the most significant factor in determining the joint strength followed by separator and susceptor. Further to corroborate the optimal parameter setting for maximum strength values, metallurgical characterization of the specimens is carried out through XRD and SEM. Specimens processed at 600 W exhibited superior properties compared to their counterparts developed at 900 W. © 2018, Springer Science+Business Media, LLC, part of Springer Nature and ASM International.
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    Effect of Power Input on Metallurgical and Mechanical Characteristics of Inconel-625 Welded Joints Processed Through Microwave Hybrid Heating
    (Springer, 2019) Badiger, R.I.; Narendranath, S.; Srinath, M.S.; Hebbale, A.M.
    In the present study, welding of Inconel-625 through the use of microwave hybrid heating (MHH) has been achieved at two power levels 600 W and 900 W in a low-cost home microwave oven. Nickel-based powder EWAC was used as filler interface between faying surfaces. Effect of power variation on the metallurgical and mechanical characteristics of the microwave welded joints has been investigated. Developed joints were characterized through XRD, optical microscope, SEM, universal testing machine and Vickers microhardness tester. XRD study of the weld zone indicated the formation of various carbides and intermetallics. Joint microstructures witnessed a completely fused weld interface without any interfacial cracks. EDS analysis of the joint microstructure revealed lesser amount of segregation of niobium and molybdenum with the specimens developed at 600 W which could be attributed to the lower heat input associated with 600 W power that also resulted in fine grain structure. Further, the specimens processed at 600 W exhibited better tensile and flexural properties when compared to their counterparts produced at 900 W power. Fractography study of the specimens revealed a combined ductile and brittle fracture. © 2019, The Indian Institute of Metals - IIM.
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    Influence of Microwave Power and EWAC-1004EN Filler Size on Characteristics of Inconel 625 and SS 304 Weldments Produced Using Microwave Irradiation Hybrid Joining System
    (Springer Nature, 2025) Kamble, D.L.; Sahu, R.K.; S, N.; Badiger, R.I.
    The present study focuses on welding of Inconel 625 (exotic) and SS 304 (general purpose) dissimilar alloys using the microwave irradiation hybrid joining system and subsequent characterization of the joint processed through microwave energy. The process parameters, namely microwave power (4.4 kW and 2.2 kW) and interfacial powder EWAC 1004 EN (average particle size: 75 µm and 25 µm) are employed. The individual influence of process parameters on weldment properties is studied. The joint specimens developed at 2.2 kW power show the enhancement of ultimate tensile strength (UTS), flexural strength (FS), and average microhardness by 33.44%, 71.42% and 31.25%, respectively, in contrast to their counterparts developed at 4.4 kW keeping particle size constant. Similarly, the UTS, FS and average microhardness of the specimens developed using EWAC-1004EN powder of average particle size (APS) 25 µm found to considerably increased by 76.07%, 32.06% and 55.55%, respectively, as compared to the joints developed using 75 µm APS with constant microwave power. This enhancement in the mechanical properties is attributed to the formation of different carbide and intermetallic phases such as NbC, Cr23C6, Cr2Ni3, Ni8Nb, and FeNi in the weld region which is evident from XRD. Furthermore, the fractured specimens obtained from tensile and flexural tests are examined using FESEM. It is observed that both ductile as well as brittle fracture occurred. This mixed fracture is particularly ascribed to the presence of secondary/ intermetallic phases in the fusion region. © King Fahd University of Petroleum & Minerals 2025.
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    Optimization of measured mechanical characteristics of selective microwave hybrid heating processed Inconel 625/ SS 304 weldments using multi-objective JAYA algorithm coupled with multi-attributes decision making R-method
    (Elsevier B.V., 2025) Singha, B.; Kamble, D.L.; Sahu, R.K.; Narendranath, S.; Badiger, R.I.
    This work focuses on the joining of Inconel-625/SS-304 using selective microwave hybrid heating (SMHH) technique. Input power, filler powder particle size, separator, and susceptor size are considered for experimentation according to the Definitive Screening Design. The multi-objectives measured are UTS, FS, and microhardness. XRD results show the intermetallic/secondary phases, and FESEM micrographs show the metallurgical bonding occurs between base metal and filler. The joint and interface region had an average microhardness of 204 ± 10 HV and 342 ± 18 HV, respectively. The UTS and FS of the weldments measured to 550 MPa and 805 MPa. MOJAYA technique is utilized for multi-objective optimization, and R-method determined the optimal process parameters. The optimal process parameters found to 2.2 kW, 25 ?m powder, 120 grit and 0.804 mm separator. The confirmation test reveals UTS ? 566 MPa, FS ? 903 MPa, and microhardness ? 365 HV, which closely matched with predicted observations. © 2024 Elsevier Ltd