Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Subject: search.filters.subject.Bainite

Search Results

Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    Investigation on grinding wear behaviour of austempered ductile iron as media material during comminution of iron ore in ball mills
    (2011) Hebbar, R.
    An attempt has been made to assess the grinding wear behaviour of austempered ductile iron (ADI) as media material in comminution of Kudremukh haematite iron ore in a ball mill. Spheroidal graphite (S.G) iron balls were austenitised at 900°C for one hour and austempered at 280°C and 380°C for different time durations. These materials were characterized by measuring hardness, carrying out X-ray diffraction analysis, studying microstructures using scanning electron microscope (SEM). Grinding wear behaviour of ADI was assessed during wet grinding at different pH of the mineral slurry. The wear resistance of ADI was compared with that of forged En 31 steel balls under similar grinding conditions. It was found that ADI balls austempered at 280°C for 30 minutes which contains lower bainite registered superior wear resistance. It was also noted that the wear resistance of ADI was more at higher pH range of the slurry. © 2011 TIIM, India.
  • No Thumbnail Available
    Item
    Microstructure and mechanical properties of austempered AISI 9255 high-silicon steel
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2018) Acharya, P.P.; Udupa, R.; Bhat, R.
    The present investigation is focused on evaluating the microstructure and mechanical properties of American Iron and Steel Institute 9255 high-silicon steel austempered at different temperatures and durations. Material characterisation was done using a scanning electron microscope and an X-ray diffractometer. Results show the bainite microstructure over a temperature range of 280–400°C. Bainite structure gains coarseness at higher temperatures at 360 and 400°C. A significant improvement in the tensile properties was observed for all austempered specimens; with a maximum tensile strength of 1852 MPa and elongation up to 35%. An excellent strain hardening response was observed from the samples austempered at temperatures of 360 and 400°C. Tensile properties were found to be superior at 15 min of austempering duration for all austempering temperatures. © 2017 Institute of Materials, Minerals and Mining.
  • No Thumbnail Available
    Item
    Structure-Property Correlation of Quenching and Partitioning Heat Treated Silicon-Manganese Steel
    (Springer Netherlands rbk@louisiana.edu, 2019) Acharya, P.P.; Bhat, R.
    The present investigation deals with the effect of varying quenching and partitioning parameters on microstructure and mechanical properties of American Iron and Steel Institute 9255 steel. The specimens were fully austenitised at 900 ?C for 45 min and then quenched at 190 ?C and followed by partitioning at various temperatures 280, 320, 360 and 400 ?C and partitioning times 15, 30, 45, 60 and 90 min for each temperature. Post heat treatment includes microstructural analysis that was carried out by using scanning electron microscope (SEM) along with electron back scattered diffraction (EBSD) and x-ray diffraction (XRD) and then correlated to the mechanical properties i.e. tensile properties and hardness of the steel. Results indicate that the specimens quenched at 190 ?C and partitioned over a temperature range 280 to 400 ?C generates multiphase microstructures containing major fraction of martensitic structure (lath and plate-type), transitional ?-carbides in tempered martensite matrix and retained austenite (RA) for all the conditions. At higher partitioning temperatures i.e. 360 and 400 ?C reveals some bainitic ferrite laths along with martensite and RA. Superior tensile strength, % elongation and modulus of toughness values of 1860 MPa, 12% and 207 MJ/m3 respectively was attained at partitioning time of 15 min at 280 ?C. © 2018, Springer Nature B.V.
  • No Thumbnail Available
    Item
    Interrupted metal deposition wire arc additive manufacturing to fabricate objects with trailered microstructures
    (Elsevier B.V., 2025) Singh, C.P.; Tiwari, V.; Kumar, A.; Kapil, S.; Singh, S.S.; Singh Rajput, A.S.
    Advances in additive manufacturing have enabled innovative approaches to creating materials with tailored properties. This study presents Interrupted Metal Deposition in Wire Arc Additive Manufacturing (IMD-WAAM) for fabricating thin walls of Functionally Graded Materials (FGMs). By controlling heat input during deposition, IMD-WAAM precisely modulates microstructural evolution. Characterization techniques, including Optical Emission Spectroscopy (OES) for composition analysis, Field Emission Scanning Electron Microscopy (FESEM), and Electron Backscatter Diffraction (EBSD) for grain-level insights, along with Continuous Cooling Transformation (CCT) diagrams from JMatPro, revealed distinct microstructural zones. Continuous deposition showed coarse ferritic structures, while a 5-second Inter-Drop Cooling Time (IDCT) produced refined ferritic and bainitic structures. These results demonstrate IMD-WAAM's ability to achieve seamless property gradation, making it a transformative method for aerospace, biomedical, and other applications requiring customized material properties. © 2025 Elsevier B.V.