Faculty Publications

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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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    Comparison of plastic collapse moment for different angled non-circular pipe bends under bending moments and internal pressure
    (Springer Science and Business Media Deutschland GmbH, 2024) Kumar, M.; Singh, M.; Kumar, A.; kumar, A.; Kamble, D.L.
    Pipe bends are a crucial component of the pipeline industry because they experience more stresses and deformations than straight pipes of the same dimensions and material properties under the same loading conditions. For a reliable and safe piping system, the plastic collapse moment of pipe bends must be estimated accurately. The current study aims to find which bending mode is critical to failure for pipe bends; for that, the collapse moment under in-plane closing (IPC), in-plane opening (IPO) and out-of-plane (OP) bending moments are compared using finite element (FE) analysis. The comparison accounts for various values of internal pressure, bend angle and initial geometric imperfection. The FE analysis considers elastic-perfectly plastic (EPP) and strain-hardening (SH) material models. Twice-elastic-slope (TES) method is implemented to evaluate plastic collapse moment for all considered cases. The comparison of collapse moment shows that under unpressurized conditions, pipe bends are critical to IPC bending moment. However, it is difficult to identify which bending mode is critical under pressurized conditions. Therefore, plastic collapse moment under all three bending modes should be known and for that plastic collapse moment equations under all bending modes should be proposed. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024.
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    Characterization of Inconel 625-SS 304 Weldments Developed by Selective Microwave Hybrid Joining Technique for Promising Applications
    (Springer, 2024) Kamble, D.L.; Sahu, R.K.; Narendranath, S.
    Production of dissimilar weldments using microwave hybrid heating is currently gaining immense impetus in the field of advanced welding. This is because such heat source could provide benefits like cost-effectiveness, rapid, volumetric, uniform and selective heating, and efficient throughput which would be significant to various industries. Till-date researchers have carried out joining of dissimilar general purpose engineering materials using microwave hybrid heat source. But attention has not been paid on the joining and characterization of dissimilar exotic-general purpose materials using the aforementioned heat source and the promising applications of the weldments. Therefore, the present article is focused on the joining of dissimilar materials- Inconel 625 and SS 304 alloys using selective microwave hybrid joining (SMHJ) technique. In SMHJ, nickel-based powder is used as a filler material, Silicon carbide (SiC) block and SiC powder are used as susceptor to increase the initial temperature. The developed weldments through SMHJ are characterized using various physico-chemical diagnostic methods. The results reveal the average micro-hardness of joint was found to be 303 ± 17 HV owing to the presence of various carbides and nitrides phase like NbC, Cr23C6, Cr2Ni3, Ni8Nb, and Fe3Ni2 in the joint zone which is evident from XRD. The average UTS of the joints found to be 448.6 MPa with an elongation of 10.93% and flexural strength observed to be 435 MPa. Further, fractography study reveals, the joint regions have mixed mode of failure. The failure was attributed to the existence of secondary phases in the joint zone. © ASM International 2023.
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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