Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

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Author: search.filters.author.Ramesh, M.R.Subject: search.filters.subject.Microstructure

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    Fabrication of stainless steel based composite by metal injection moulding
    (Elsevier Ltd, 2018) Veeresh Nayak, C.; Ramesh, M.R.; Desai, V.; Kumar Samanta, S.K.
    Metal injection moulding (MIM) is large scale manufacturing method, for creation of complex shapes and miniature parts by a combination of plastic injection moulding with the flexibility in sintering of metal particulates. In current investigation binder comprised of paraffin wax, polyethylene glycol, stearic acid and low-density polyethylene are developed for moulding of composite powders of SS316L+WC-CrC-Ni, and sintered at 1200°C under hydrogen purged atmosphere. Composites are characterised with respect to rheological, thermal properties and microstructure by scanning electron microscopy, microhardness and density. Properties of sintering temperature and heating rate on the above properties have been evaluated to obtain a defect-free composite. © 2017 Elsevier Ltd.
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    High temperature tribological studies of cold sprayed nickel based alloy on low carbon steels
    (Elsevier Ltd, 2019) Padmini, B.V.; Mathapati, M.; Niranjan, H.B.; Sampathkumaran, P.; Seetharamu, S.; Ramesh, M.R.; Mohan, N.
    The boiler steels of grades SAE213 T11 and T22, find extensive applications in heat exchanger tubes, paper and pulp, chemical industries and refineries. Further, these steels are also used in shafts, cylinders, bearings, and in automotive transmission parts and these aspects are less explored. They experience low wear life in specific components, both at room and slightly higher temperature regimes. In order to protect them from these damages, coatings are deployed involving many techniques like HVOF, Plasma spray, Cold spray etc. so that the life of the components get extended. In cold spray coatings, the powders are fed at very high impact velocities of up to 1200 m/s on the substrate and undergo plastic deformation during the impact. There is no oxidation of the powder takes place during the process, as the coating is done at very less temperature and this is one of the lead characteristic of cold spray technique. This particular work mainly focuses on evaluating the tribological behaviour of nickel based super alloy powder on T11 and T22 low alloy steels by cold spray method, using pin on disc machine both at room temperature as well as at 200, 300 and 400 °C. The associated tests such as hardness, porosity, and microstructure have been undertaken to support the wear data. The wear damage assessment has been carried out using scanning electron microscope to arrive at the mechanism and also to give credence to the wear data. © 2019 Elsevier Ltd.
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    DRY SLIDING WEAR RESISTANCE OF HVOF SPRAYED IRON-BASED COMPOSITE COATINGS ALLOYED WITH CARBIDES ACROSS VARIOUS TEMPERATURES
    (American Society of Mechanical Engineers (ASME), 2025) Aprameya, C.R.; Chandramouli, T.V.; Joladarashi, S.; Ramesh, M.R.
    Maraging steel, widely used in aerospace applications for its remarkable strength and toughness, often faces challenges related to surface wear resistance in high-stress environments. This study investigates the dry sliding wear performance of Fe-based coatings allied with carbides, applied onto maraging 250-grade steel using the High-Velocity Oxy-Fuel (HVOF) thermal spraying surface modification technique. The objective is to assess the tribological behavior of these as-sprayed samples under varying circumstances. Dry wear tests were conducted at both room temperature and 300 °C under a normal load of 30 N. The study comprehensively investigates the factors influencing wear resistance by analysing key microstructural and mechanical properties, including microhardness, porosity, and bond strength. Advanced characterisation techniques were employed, including Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) for surface morphology and elemental analysis and X-ray diffraction (XRD) for phase identification. A 3D profilometer was utilised to measure wear scar volume and quantify volumetric wear loss precisely. At room temperature, abrasive wear dominated, with ploughing and furrows as primary material removal mechanisms. Notably, the 316L-20%Cr3C2 coating exhibited better wear resistance compared to the 17-4ph-20%Cr3C2 coating. This enhanced performance is attributed to the carbide reinforcements, which significantly increased hardness and improved wear resistance under high temperatures. These findings emphasize the potential of carbide-reinforced HVOF coatings as an effective surface engineering approach for enhancing the performance and service life of maraging steel under harsh operational conditions, particularly those involving high temperatures and severe wear. © © 2025 by ASME.